Calculating Shock Position in CD Nozzle JoshTheEngineer 2018-01-24 | How do we calculate the position of a normal shock in a converging-diverging (CD) nozzle? In this video, we will go through the necessary calculations in order to compute the area ratio of the normal shock (and thus its position if you know how the nozzle's area changes with axial position).For the code used at the end of the video, check out the link below in the RELEVANT LINKS section.===== RELEVANT VIDEOS =====→ Converging-Diverging Nozzlegoo.gl/nC5hzb→ CD Nozzle Pressure Delineationsgoo.gl/rQEA6S→ Normal Shock Relationsgoo.gl/8BaJDH→ Normal Shock Examplegoo.gl/HJfH3B===== RELEVANT LINKS =====► Solving the Area-Mach Number Relationhttp://www.joshtheengineer.com/2016/11/16/solving-the-area-mach-number-relation► CD Nozzle Pressure Delineationshttp://www.joshtheengineer.com/2017/12/17/converging-diverging-nozzle-pressure-delineations► MATLAB Codehttp://www.joshtheengineer.com/2018/01/24/normal-shock-in-converging-diverging-nozzle===== REFERENCES =====→ Modern Compressible Flow, John D. Anderson (goo.gl/tBPr9n)→ Elements of Gasdynamics, Lipemann and Roshko (goo.gl/7mUFEi)→ Gas Dynamics, Zucrow and Hoffman (goo.gl/cVAa2G)
You Should Be Keeping a Research Notebook JoshTheEngineer 2021-06-02 | A detailed research notebook is an indispensable tool for keeping track of what you've done and when you did it. In this video, I'll walk you through a few simple rules I use for my notebooks, and show examples of how to implement them in yours. If you think keeping notes is a waste of time, then maybe this video isn't for you, and we can't be friends.00:00 - Introduction00:20 - Background00:49 - Notebook types01:49 - Writing utensils02:22 - General content structure02:47 - Page numbering03:11 - Dates and highlighting04:33 - Referencing pages and notebooks05:10 - Adding figures05:22 - Extra notes, corrections06:05 - Finishing up===== NOTES =====- This is how I do it. There is no right answer here. Do what you want.===== LINKS =====Note: These are Amazon affiliate links. If you use these links to purchase any of the items, it helps me out a little bit.► Oxford Composition Notebook (100 sheets, quad ruled), $4.49 at this momentamzn.to/3wTIZLV► National Laboratory Notebook (96 sheets, quad ruled), $10.79 at this momentamzn.to/3yXHYEb► Adams Record Ledger (300 pages, my preference), $34.11 at this momentamzn.to/2S0aaFO► Pilot G2 0.7mm (five-color pack: black, blue, red, green, purple), $6.79 at the momentamzn.to/3uH76vI► Pilot G2 0.7mm (5 black, 5 blue), $15.97 at the momentamzn.to/3vGYExX► BIC Brite Liner Grip Highlighter (five-color pack: pink, blue, green, orange, yellow), $4.89 at the momentamzn.to/34AiZcl
Schlieren Mirrors: Spherical vs. Parabolic JoshTheEngineer 2021-02-21 | Both spherical and parabolic mirrors are used in schlieren systems, but which one should you use and when? In this video, we'll look at how the two mirrors reflect light for two scenarios:1) How does the mirror reflect the light when the incident rays are collimated (parallel)?2) How does the mirror reflect the light when the incident rays emanate from the 2f point?We'll see why the spherical mirror is ideal for the double-pass system, while the parabolic mirror is ideal for the Z-type system, but also why you can use either mirror in both systems without much loss in quality.===== RELEVANT VIDEOS =====► How To: Build Your Own Schlieren Setupyoutube.com/watch?v=IZ0bYi9UFv8===== NOTES =====- All simulations assume on-axis performance, even though in the schematics I show, the light source is located off-axis. If you want to use a beamsplitter for the double-pass system, then you would have on-axis light through the system.- I'm aware the spherical mirror focusing issue is called spherical aberration. Sometimes I deliberately choose not to include terminology depending on the intended audience of the video.===== RELEVANT REFERENCES =====- Any optics book
Creating Schematics in PowerPoint and Inkscape JoshTheEngineer 2021-02-10 | When making schematics for papers you're writing, it's best to create vector-format images so that they don't appear pixelated. In this video, I'll show you two methods of creating and exporting schematics, using 1) PowerPoint and 2) Inkscape. Obviously there are many ways to do this, so if you do it differently, that's fantastic.00:00 - Motivation00:36 - PowerPoint: Getting ready01:01 - PowerPoint: Create schematic02:48 - PowerPoint: Save as PDF03:22 - PowerPoint: Resize slides06:18 - PowerPoint: Viewing PNG vs. PDF in LaTeX06:53 - PowerPoint: Multiple schematics09:06 - Inkscape: Getting ready10:06 - Inkscape: Create some text10:43 - Inkscape: Keys and mouse clicks11:19 - Inkscape: Create schematic13:18 - Inkscape: Create duplicate schematic14:10 - Inkscape: Unicode symbols14:56 - Inkscape: Larger equations16:22 - Inkscape: Exporting PDF19:12 - Inkscape: Viewing two PDFs in LaTeX19:39 - Inkscape: Multiple schematics in one document===== LINKS =====► Inkscape downloadinkscape.org► Introduction to LaTeXyoutube.com/watch?v=qjLqM1YYNN4===== THUMBNAIL =====► PowerPoint LogoUT Dallas, CC BY-SA 4.0 creativecommons.org/licenses/by-sa/4.0, via Wikimedia Commons► Inkscape LogoInkscape Community (original logo), This vector image was created with Inkscape by Speck-Made, and then manually replaced by sarang., CC0, via Wikimedia Commons
Introduction to JabRef JoshTheEngineer 2021-01-31 | JabRef is used as a reference manager, and in this video we'll go through some more of the details for how to use it efficiently. For more information regarding using JabRef for writing papers, see my "Introduction to Latex" video (link below).00:00 - Introduction00:31- Dark theme00:53 - Creating a library01:14 - When to create new libraries03:36 - Citation keys04:57 - Importing citations and editing entries (e.g. AIAA)10:36 - Importing citations and editing entries (e.g. Applied Optics)12:22 - Importing using DOI13:18 - Importing using ISBN13:53 - Special table columns14:40 - "Read status" column15:00 - "Quality" column15:55 - "Linked files" column17:34 - "Linked identifiers" column18:18 - Using groups and "Groups" column20:54 - Updating references in Texmaker22:08 - Final thoughts===== VIDEOS =====►Introduction to Latexyoutube.com/watch?v=qjLqM1YYNN4===== TEMPLATES =====►Download from my GitHubgithub.com/jte0419/LaTeX_Templates===== USEFUL REFERENCES =====JabRef: docs.jabref.orgWikibook: en.wikibooks.org/wiki/LaTeXOverleaf: overleaf.comStack Exchange: tex.stackexchange.com===== PROGRAMS FOR LATEX =====Texmaker: xm1math.net/texmakerMiKTeX: miktex.orgJabRef: jabref.orgSumatra PDF: sumatrapdfreader.org/free-pdf-reader.html===== NOTES =====- There are a bunch of options and customization features I didn't cover in the video.===== ERRORS =====Please let me know if you find any errors in my video, or in the template files provided.
Introduction to LaTeX JoshTheEngineer 2021-01-24 | Are you interested in creating nice-looking documents, while avoiding the headaches generally associated with normal Word documents? In this video, I'll show you how to get started with LaTeX, including what programs you need (all free), how to put together a simple document and view the resulting PDF, and give you links to some of my templates that you can try out for yourself.00:00 - Who should use LaTeX?01:03 - Useful references01:22 - Programs you'll need01:49 - Texmaker download02:06 - MiKTeX download02:27 - JabRef download02:45 - Sumatra PDF download04:00 - Texmaker settings05:38 - Starting a document07:40 - Adding references11:27 - Adding figures14:12 - Adding equations16:24 - Templates===== TEMPLATES =====►Download from my GitHubgithub.com/jte0419/LaTeX_Templates===== PROGRAMS =====Texmaker: xm1math.net/texmakerMiKTeX: miktex.orgJabRef: jabref.orgSumatra PDF: sumatrapdfreader.org/free-pdf-reader.html===== USEFUL REFERENCES =====Wikibook: en.wikibooks.org/wiki/LaTeXOverleaf: overleaf.comStack Exchange: tex.stackexchange.com===== NOTES =====- There are so many ways to accomplish the same thing with LaTeX, so if you see something I did and you do it a different way, that's great.- I'm deliberately not going into a bunch of details and explanation in this video.===== ERRORS =====Please let me know if you find any errors in my video, or in the template files provided.
ImageJ Start-Up Macro JoshTheEngineer 2021-01-23 | If you write custom macros for ImageJ, and you want them to load upon start-up (instead of navigating to its folder and double-clicking every time), then this video will show you how to accomplish that.The motivation for this video was to show how to add the BOS_Save_Sequence_v2.ijm file to the Plugins → Macros menu for use with my Background Oriented Schlieren code/video (see links below).===== LINKS =====►DIY Background Oriented Schlieren Videoyoutube.com/watch?v=VCUN59x0LF4►Updated ImageJ Macro for DIY BOSyoutube.com/watch?v=GXapOtBf52o&t=5s►GitHub Codegithub.com/jte0419/Background_Oriented_Schlieren►My Website Codehttp://www.joshtheengineer.com/2019/10/20/how-to-take-pictures-like-nasa-using-background-oriented-schlieren-bos
BOS ImageJ Macro Update JoshTheEngineer 2021-01-17 | In my DIY Background Oriented Schlieren video, I provided a macro for use in ImageJ that automates the process of extracting sequential images from a video for use in my MATLAB or Python code. That version appears to be outdated now, so this video quickly outlines the updated macro (v2). This updated version is available at the links below.===== LINKS =====GitHub (download version 2 of the .ijm macro)►github.com/jte0419/Background_Oriented_SchlierenMy website (download version 2 of the .ijm macro)►http://www.joshtheengineer.com/2019/10/20/how-to-take-pictures-like-nasa-using-background-oriented-schlieren-bosDIY BOS YouTube Video►youtube.com/watch?v=VCUN59x0LF4
Multi-Airfoil Source/Vortex Panel Method JoshTheEngineer 2020-07-12 | We've finally reached the last video in my panel method series. Here, I'll show you how to update my single-airfoil SPVP code to be able to solve multi-airfoil systems. After explaining the updates (which takes about 20 minutes), we'll go through some examples of different airfoils and systems.===== CODE =====► My websitehttp://www.joshtheengineer.com/2020/07/12/multi-airfoil-source-vortex-panel-method► GitHubgithub.com/jte0419/Panel_Methods===== RELEVANT VIDEOS =====► Panel Methods Playlistyoutube.com/watch?v=bWjo3N9COz4&list=PLxT-itJ3HGuUDVMuWKBxyoY8Dm9O9qstP► Source Panel Method: Airfoilyoutube.com/watch?v=fdNOYdwY9Bw► Vortex Panel Method: Airfoilyoutube.com/watch?v=JL2fz-xTTT0► Source/Vortex Panel Method: System of Equationsyoutube.com/watch?v=bc_pkKGEypU► Source/Vortex Panel Methods: Airfoilyoutube.com/watch?v=V77QTAgZuqw===== NOTES =====→ I haven't coded this particular script in Python, and I'm not sure if I'm going to. You can download my single-airfoil SPVP code and update it based on my MATLAB code if you want to.→ More airfoils and more panels per airfoil will cause the streamline calculations to take longer.→ The grid for the streamline has to have equal X and Y points at the moment. I know there's an error since it doesn't work for irregular grids, but I'm not planning on fixing it at the moment.===== ERRORS =====→ If you see an error in the video, please let me know and I will include it here.===== REFERENCES =====Note: the links are Amazon affiliate links. If you do happen to want to buy the book and use the link below, it helps me out a little.► Fundamentals of Aerodynamics, Andersonamzn.to/3emVuXU► Foundations of Aerodynamics, Kuethe and Chowamzn.to/2yMg1Vi► Theory of Wing Sections, Abbott and Doenhoffamzn.to/2wvZyUt
Source/Vortex Panel Method: Airfoil JoshTheEngineer 2020-06-23 | The source/vortex panel method code in this video is a combination of the source and vortex panel methods that I have used in my previous videos. This code solves some of the problems that were mentioned in my "Vortex Panel Method: Airfoil" video.In this penultimate video of my Panel Methods series, we will look at how to populate the matrix system to obtain the solution of the source and vortex strengths. Then we'll go through a bunch of examples of different airfoils to see how well this method works. Comparisons of the lift coefficient, moment coefficient, and pressure coefficient to XFOIL will be made.In the next (and last) video of this series, we will update this code to be able to work with any number of airfoils.===== CODE =====► My websitehttp://www.joshtheengineer.com/2020/06/22/source-vortex-panel-method-airfoil► GitHubgithub.com/jte0419/Panel_Methods===== RELEVANT VIDEOS =====► Panel Methods Playlistyoutube.com/watch?v=bWjo3N9COz4&list=PLxT-itJ3HGuUDVMuWKBxyoY8Dm9O9qstP► Source Panel Method: Airfoilyoutube.com/watch?v=fdNOYdwY9Bw► Vortex Panel Method: Airfoilyoutube.com/watch?v=JL2fz-xTTT0► Source/Vortex Panel Method: System of Equationsyoutube.com/watch?v=bc_pkKGEypU===== NOTES =====→ The code is also available in Python, but I didn't include it in this video.→ The streamline computation section in the Python code takes a really long time to run in comparison to the same MATLAB code. I'm assuming it has to do with the external function calls taking longer, but if you have any suggestions on speeding up that aspect of the code, please let me know.===== ERRORS =====→ If you see an error in the video, please let me know and I will include it here.===== REFERENCES =====Note: the links are Amazon affiliate links. If you do happen to want to buy the book and use the link below, it helps me out a little.► Fundamentals of Aerodynamics, Andersonamzn.to/3emVuXU► Foundations of Aerodynamics, Kuethe and Chowamzn.to/2yMg1Vi► Theory of Wing Sections, Abbott and Doenhoffamzn.to/2wvZyUt
Source/Vortex Panel Method: System of Equations JoshTheEngineer 2020-05-10 | In this video, we will combine the source panel method and vortex panel method into a hybrid source/vortex panel method that is more robust than our previous vortex panel method implementation, and which follows the method of Hess and Smith. In the next video, we will implement the equations shown here in the MATLAB and Python code.===== RELEVANT VIDEOS =====► Panel Methods Playlistyoutube.com/watch?v=bWjo3N9COz4&list=PLxT-itJ3HGuUDVMuWKBxyoY8Dm9O9qstP ► I(ij) Geometric Integral Derivation youtube.com/watch?v=76vPudNET6U► J(ij) Geometric Integral Derivationyoutube.com/watch?v=JRHnOsueic8► Mx(pj) and My(pj) Geometric Integral Derivationyoutube.com/watch?v=BnPZjGCatcg► K(ij) Geometric Integral Derivationyoutube.com/watch?v=5lmIv2CUpoc► L(ij) Geometric Integral Derivationyoutube.com/watch?v=IxWJzwIG_gY► Nx(pj) and Ny(pj) Geometric Integral Derivationyoutube.com/watch?v=TBwBnW87hso► Source Panel Method: Airfoilyoutube.com/watch?v=fdNOYdwY9Bw► Vortex Panel Method: Airfoilyoutube.com/watch?v=JL2fz-xTTT0===== NOTES =====- On the whiteboard at 13:55 (and on), the final term on the RHS (b array) has a beta_N, which for this 3-panel problem, can just be written as beta_3.===== ERRORS =====- If you see an error in the video, please let me know and I will include it here.===== REFERENCES =====Note: the links are Amazon affiliate links. If you do happen to want to buy the book and use the link below, it helps me out a little.► Fundamentals of Aerodynamics, Andersonamzn.to/3emVuXU► Foundations of Aerodynamics, Kuethe and Chowamzn.to/2yMg1Vi► Theory of Wing Sections, Abbott and Doenhoffamzn.to/2wvZyUt
Vortex Panel Method: Airfoil JoshTheEngineer 2020-04-28 | The vortex panel method code in this video is an adaptation of the source panel method code from a few videos ago. The only change we've made between the codes is the formulation of the matrix system of equations (including the addition of the Kutta condition equation).We'll look at a few examples of the code working like you would expect, and compare resulting lift and moment coefficients to the XFOIL results. Then we'll look at a few cases where the code seems to fall apart, which is the motivation for my next two videos, the combined source/vortex panel method. ===== WHERE ARE WE GOING? =====→ The limitations in this video motivate the need for a more robust implementation of the VPM.→ I will derive the combined SPM/VPM formulation and code it to show how good we can get the results for a pretty simple implementation.→ We can finally extend the SPM/VPM formulation to multiple separate airfoil elements. This will be the last video in the series.===== CODE =====► My websitehttp://www.joshtheengineer.com/2020/06/21/vortex-panel-method-airfoil► GitHubgithub.com/jte0419/Panel_Methods===== RELEVANT VIDEOS =====► Panel Methods Playlistyoutube.com/watch?v=bWjo3N9COz4&list=PLxT-itJ3HGuUDVMuWKBxyoY8Dm9O9qstP► Panel Method Geometryyoutube.com/watch?v=kIqxbd937PI► Building More Complex Flowsyoutube.com/watch?v=EKzbwJvKcmw► Flow Around an Airfoilyoutube.com/watch?v=cLdv1UfX1g8► Normal Velocity Geometric Integral [K(ij)]youtube.com/watch?v=5lmIv2CUpoc► Tangential Velocity Geometric Integral [L(ij)]youtube.com/watch?v=IxWJzwIG_gY► Streamline Geometric Integral VPM [Nx(ij) and Ny(ij)]youtube.com/watch?v=TBwBnW87hso► Solving the System of Equations: VPMyoutube.com/watch?v=j3ETHFBiYOg► Source Panel Method: Airfoilyoutube.com/watch?v=fdNOYdwY9Bw===== NOTES =====→ I'll add notes here if I need to.===== ERRORS =====→ If you see an error in the video, please let me know and I will include it here.===== REFERENCES =====Note: the links are Amazon affiliate links. If you do happen to want to buy the book and use the link below, it helps me out a little.► Fundamentals of Aerodynamics, Andersonamzn.to/3emVuXU► Foundations of Aerodynamics, Kuethe and Chowamzn.to/2yMg1Vi► Theory of Wing Sections, Abbott and Doenhoffamzn.to/2wvZyUt
Vortex Panel Method: System of Equations JoshTheEngineer 2020-04-12 | In this video, we will build up the system of equations we need to solve in order to get the vortex panel strengths. First, we get N equations by setting the normal velocity at every control point equal to zero. Next, we get an equation for the Kutta condition. If we simply add this equation into the system of equations, we end up with N+1 equations for N unknowns, which is over-constrained. Instead, we will replace the last normal velocity equation with the Kutta condition equation. We can now solve the system of equations to get the vortex panel strengths.In the next video, we will adapt my SPM code into the VPM code, look at some results, compare to the Kuethe and Chow implementation, and motivate the need for my combined SP/VP implementation.===== RELEVANT VIDEOS =====► Panel Methods Playlistyoutube.com/watch?v=bWjo3N9COz4&list=PLxT-itJ3HGuUDVMuWKBxyoY8Dm9O9qstP► Source Panel Method: System of Equationsyoutube.com/watch?v=ep7vPzGYsbw► K(ij) Geometric Integral Derivationyoutube.com/watch?v=5lmIv2CUpoc► L(ij) Geometric Integral Derivationyoutube.com/watch?v=IxWJzwIG_gY► Nx(pj) and Ny(pj) Geometric Integral Derivationyoutube.com/watch?v=TBwBnW87hso===== NOTES =====- At 2:56, I show a screenshot from the Kuethe and Chow book (1976), and this expression does not have a negative sign. In their book, they generally take the negative sign out of the summation and move it to the uniform flow term immediately, hence the missing negative sign. The focus of that screenshot is actually the text below the equation.===== ERRORS =====- If you see an error in the video, please let me know and I will include it here.===== REFERENCES =====Note: the links are Amazon affiliate links. If you do happen to want to buy the book and use the link below, it helps me out a little.► Fundamentals of Aerodynamics, Andersonamzn.to/3emVuXU► Foundations of Aerodynamics, Kuethe and Chowamzn.to/2yMg1Vi► Theory of Wing Sections, Abbott and Doenhoffamzn.to/2wvZyUt
Streamline Geometric Integral VPM [Nx(pj) and Ny(pj)] JoshTheEngineer 2020-04-05 | In this video, we go through the X and Y velocity expression geometric integrals for the vortex panel method. This is the last geometric integral derivation we will need.===== RELEVANT VIDEOS =====► Panel Methods Playlistyoutube.com/watch?v=bWjo3N9COz4&list=PLxT-itJ3HGuUDVMuWKBxyoY8Dm9O9qstP===== NOTES =====- I'll add notes here if I need to.===== ERRORS =====- If you see an error in the video, please let me know and I will include it here.===== REFERENCES =====Note: the links are Amazon affiliate links. If you do happen to want to buy the book and use the link below, it helps me out a little.► Fundamentals of Aerodynamics, Andersonamzn.to/3emVuXU► Foundations of Aerodynamics, Kuethe and Chowamzn.to/2yMg1Vi► Theory of Wing Sections, Abbott and Doenhoffamzn.to/2wvZyUt
Vortex Panel Method: Tangential Velocity Geometric Integral [L(ij)] JoshTheEngineer 2020-04-05 | We just finished the video for the source panel method (SPM), and saw its inherent limitations as we looked at some results for an airfoil. Now, to be able to code up the vortex panel method (VPM), we need to compute geometric integrals similar to those for the SPM. These geometric integrals come from the expressions for the normal and tangential velocity.In this video, we derive the geometric integral from the tangential velocity expression (Lij). In the next video, we will derive the X and Y velocity expression geometric integrals needed for the streamline calculations, after which we can construct a system of equations to solve for the vortex panel strengths.===== RELEVANT VIDEOS =====► Panel Methods Playlistyoutube.com/watch?v=bWjo3N9COz4&list=PLxT-itJ3HGuUDVMuWKBxyoY8Dm9O9qstP===== NOTES =====- I'll add notes here if I need to.===== ERRORS =====- If you see an error in the video, please let me know and I will include it here.===== REFERENCES =====Note: the links are Amazon affiliate links. If you do happen to want to buy the book and use the link below, it helps me out a little.► Fundamentals of Aerodynamics, Andersonamzn.to/3emVuXU► Foundations of Aerodynamics, Kuethe and Chowamzn.to/2yMg1Vi► Theory of Wing Sections, Abbott and Doenhoffamzn.to/2wvZyUt
Vortex Panel Method: Normal Velocity Geometric Integral [K(ij)] JoshTheEngineer 2020-04-05 | We just finished the videos for the source panel method (SPM), and saw its inherent limitations as we looked at some results for an airfoil. Now, to be able to code up the vortex panel method (VPM), we need to compute geometric integrals similar to those for the SPM. These geometric integrals come from the expressions for the normal and tangential velocity.In this video, we derive the geometric integral from the normal velocity expression (Kij). In the next video, we will derive the geometric integral from the tangential velocity expression (Lij). Finally, we will derive the X and Y velocity expression geometric integrals needed for the streamline calculations, after which we can construct a system of equations to solve for the vortex panel strengths.===== RELEVANT VIDEOS =====► Panel Methods Playlistyoutube.com/watch?v=bWjo3N9COz4&list=PLxT-itJ3HGuUDVMuWKBxyoY8Dm9O9qstP===== NOTES =====- I'll add notes here if I need to.===== ERRORS =====- If you see an error in the video, please let me know and I will include it here.===== REFERENCES =====Note: the links are Amazon affiliate links. If you do happen to want to buy the book and use the link below, it helps me out a little.► Fundamentals of Aerodynamics, Andersonamzn.to/3emVuXU► Foundations of Aerodynamics, Kuethe and Chowamzn.to/2yMg1Vi► Theory of Wing Sections, Abbott and Doenhoffamzn.to/2wvZyUt
Source Panel Method: Airfoil JoshTheEngineer 2020-03-06 | Flows over a circular cylinder are a bit boring, so here we apply the same code (with a couple minor tweaks) to the flow over an airfoil. In this video, we add two code blocks: the first is for loading and creating the airfoil, and the second is to compute the circulation around an ellipse that encompasses the airfoil. Everything else from the previous video (Source Panel Method: Circular Cylinder) is the same. The results we get in this video motivate the need for the vortex panel method. ===== WHERE ARE WE GOING? =====→ I will need to go through the derivations for the geometric integrals for the VPM (which are similar to the SPM derivations).→ We will then implement the VPM and see some of its limitations. These limitations will motivate the need for a more robust implementation of the VPM.→ I will derive the combined SPM/VPM formulation and code it to show how good we can get the results for a pretty simple implementation.→ We can finally extend the SPM/VPM formulation to multiple separate airfoil elements. This will be the last video in the series.===== CODE =====► My websitehttp://www.joshtheengineer.com/2020/03/05/source-panel-method-airfoil► GitHubgithub.com/jte0419/Panel_Methods===== RELEVANT VIDEOS =====► Panel Methods Playlistyoutube.com/watch?v=bWjo3N9COz4&list=PLxT-itJ3HGuUDVMuWKBxyoY8Dm9O9qstP► Panel Method Geometryyoutube.com/watch?v=kIqxbd937PI► Building More Complex Flowsyoutube.com/watch?v=EKzbwJvKcmw► Flow Around an Airfoilyoutube.com/watch?v=cLdv1UfX1g8► Normal Velocity Geometric Integral [I(ij)]youtube.com/watch?v=76vPudNET6U► Tangential Velocity Geometric Integral [J(ij)]youtube.com/watch?v=JRHnOsueic8► Streamline Geometric Integral SPM [Mx(ij) and My(ij)]youtube.com/watch?v=BnPZjGCatcg► Solving the System of Equationsyoutube.com/watch?v=ep7vPzGYsbw► Source Panel Method: Circular Cylinderyoutube.com/watch?v=zIrDfEz-5mc===== NOTES =====→ I'll add notes here if I need to.===== ERRORS =====→ If you see an error in the video, please let me know and I will include it here.===== REFERENCES =====Note: the links are Amazon affiliate links. If you do happen to want to buy the book and use the link below, it helps me out a little.► Fundamentals of Aerodynamics, Andersonamzn.to/3emVuXU► Foundations of Aerodynamics, Kuethe and Chowamzn.to/2yMg1Vi► Theory of Wing Sections, Abbott and Doenhoffamzn.to/2wvZyUt
Source Panel Method: Circular Cylinder JoshTheEngineer 2020-02-29 | Here we are. We finally have all the mathematical information needed to code up the source panel method. In this video, we take the code we had from the panel method geometry video, and add in the following: computation of the source panel strengths, computation of the panel tangential velocities and pressure coefficients, and computation of the grid X and Y velocities (for streamline plotting).This video uses a circular cylinder geometry because it is a convenient test case where we can compare the pressure coefficients on the panels to an analytical solution. If your code doesn't work with a circular cylinder, it's not a good idea to move on to harder geometries.===== WHERE ARE WE GOING? =====→ The next video will be very similar to this one; the source panel method solution for airfoil geometries.→ We will see some limitations in the SPM which will motivate the need for the vortex panel method (VPM).→ I will need to go through the derivations for the geometric integrals for the VPM (which are similar to the SPM derivations).→ We will then implement the VPM and see some of its limitations. These limitations will motivate the need for a more robust implementation of the VPM.→ I will derive the combined SPM/VPM formulation and code it to show how good we can get the results for a pretty simple implementation.→ We can finally extend the SPM/VPM formulation to multiple separate airfoil elements. This will be the last video in the series.===== CODE =====► My websitehttp://www.joshtheengineer.com/2020/02/29/source-panel-method-circular-cylinder► GitHubgithub.com/jte0419/Panel_Methods===== RELEVANT VIDEOS =====► Panel Methods Playlistyoutube.com/watch?v=bWjo3N9COz4&list=PLxT-itJ3HGuUDVMuWKBxyoY8Dm9O9qstP► Panel Method Geometryyoutube.com/watch?v=kIqxbd937PI► Building More Complex Flowsyoutube.com/watch?v=EKzbwJvKcmw► Flow Around an Airfoilyoutube.com/watch?v=cLdv1UfX1g8► Normal Velocity Geometric Integral [I(ij)]youtube.com/watch?v=76vPudNET6U► Tangential Velocity Geometric Integral [J(ij)]youtube.com/watch?v=JRHnOsueic8► Streamline Geometric Integral SPM [Mx(ij) and My(ij)]youtube.com/watch?v=BnPZjGCatcg► Solving the System of Equationsyoutube.com/watch?v=ep7vPzGYsbw===== NOTES =====→ I forgot to add the pop filter in front of my microphone for this video, so I apologize in advance.===== ERRORS =====→ If you see an error in the video, please let me know and I will include it here.===== REFERENCES =====Note: the links are Amazon affiliate links. If you do happen to want to buy the book and use the link below, it helps me out a little.► Fundamentals of Aerodynamics, Andersonamzn.to/3emVuXU► Foundations of Aerodynamics, Kuethe and Chowamzn.to/2yMg1Vi► Theory of Wing Sections, Abbott and Doenhoffamzn.to/2wvZyUt
Source Panel Method: System of Equations JoshTheEngineer 2020-01-26 | After solving for the geometric integral from the previous video (Iij), we have the expression for the normal velocity on a panel's control point in terms of variables we know. Since we have N unknowns (where N is the number of panels approximating the airfoil surface), we need N equations to solve the system.This video goes through how to set up the system of equations that needs to be solved in order to obtain each panel's source strength.===== RELEVANT VIDEOS =====► Panel Methods Playlistyoutube.com/watch?v=bWjo3N9COz4&list=PLxT-itJ3HGuUDVMuWKBxyoY8Dm9O9qstP► Panel Method Geometryyoutube.com/watch?v=kIqxbd937PI► Building More Complex Flowsyoutube.com/watch?v=EKzbwJvKcmw► Flow Around an Airfoilyoutube.com/watch?v=cLdv1UfX1g8► Normal Velocity Geometric Integral [I(ij)]youtube.com/watch?v=76vPudNET6U► Tangential Velocity Geometric Integral [J(ij)]youtube.com/watch?v=JRHnOsueic8► Streamline Geometric Integral SPM [Mx(ij) and My(ij)]youtube.com/watch?v=BnPZjGCatcg===== NOTES =====→ To solve the system of equations, I'm using the programmatic function (x = A\b). This takes care of the solution method for you, but you can also use your own Gaussian elimination solver, for instance. Here is a link to the MATLAB documentation for the solver:mathworks.com/help/matlab/ref/mldivide.html===== ERRORS =====→ If you see an error in the video, please let me know and I will include it here.===== REFERENCES =====Note: the links are Amazon affiliate links. If you do happen to want to buy the book and use the link below, it helps me out a little.► Fundamentals of Aerodynamics, Andersonamzn.to/3emVuXU► Foundations of Aerodynamics, Kuethe and Chowamzn.to/2yMg1Vi► Theory of Wing Sections, Abbott and Doenhoffamzn.to/2wvZyUt
Streamline Geometric Integral SPM [Mx(pj) and My(pj)] JoshTheEngineer 2020-01-25 | We went through the derivations of the normal velocity geometric integral (Iij) and the tangential geometric integral (Jij). The Iij term is used in the expression to solve for the source panel strengths. The Jij term is used in the expression to solve for the velocity of the flow on each panel. In order to compute the flowfield around the airfoil (off the airfoil), we need to know the X and Y components of the velocity at arbitrary grid points (similar to a CFD solution).In this video, we go through the derivation of the X and Y velocity geometric integrals (Mx(ij) and My(ij)). These will allow us to compute the flowfield pressure coefficients and the streamlines around the airfoil. Much of this derivation is exactly the same as the Iij derivation, so I will refer you to that video for those details.===== RELEVANT VIDEOS =====► Panel Methods Playlistyoutube.com/watch?v=bWjo3N9COz4&list=PLxT-itJ3HGuUDVMuWKBxyoY8Dm9O9qstP► Panel Method Geometryyoutube.com/watch?v=kIqxbd937PI► Building More Complex Flowsyoutube.com/watch?v=EKzbwJvKcmw► Flow Around an Airfoilyoutube.com/watch?v=cLdv1UfX1g8► Normal Velocity Geometric Integral [I(ij)]youtube.com/watch?v=76vPudNET6U► Tangential Velocity Geometric Integral [J(ij)]youtube.com/watch?v=JRHnOsueic8 ===== NOTES =====- I'll add notes here if I need to.===== ERRORS =====- If you see an error in the video, please let me know and I will include it here.===== REFERENCES =====Note: the links are Amazon affiliate links. If you do happen to want to buy the book and use the link below, it helps me out a little.► Fundamentals of Aerodynamics, Andersonamzn.to/3emVuXU► Foundations of Aerodynamics, Kuethe and Chowamzn.to/2yMg1Vi► Theory of Wing Sections, Abbott and Doenhoffamzn.to/2wvZyUt
Source Panel Method: Tangential Velocity Geometric Integral [J(ij)] JoshTheEngineer 2020-01-25 | In the previous video (Geometric Integral Iij), we went through the full derivation of the geometric integral for the normal partial derivative, which was needed to solve for the source panel strengths. In this video, we will go through the (very similar) derivation of the tangential partial derivative geometric integral, which is needed to solve for the panel velocities, and thus the panel pressure coefficients.This derivation is almost exactly the same as the normal geometric integral derivation, but there are some slight differences. Where it is exactly the same, I will refer you back to my other video (Iij) so we don't make this video longer than it needs to be.===== RELEVANT VIDEOS =====► Panel Methods Playlistyoutube.com/watch?v=bWjo3N9COz4&list=PLxT-itJ3HGuUDVMuWKBxyoY8Dm9O9qstP► Panel Method Geometryyoutube.com/watch?v=kIqxbd937PI► Building More Complex Flowsyoutube.com/watch?v=EKzbwJvKcmw► Flow Around an Airfoilyoutube.com/watch?v=cLdv1UfX1g8► Normal Velocity Geometric Integral, Iijyoutube.com/watch?v=76vPudNET6U===== NOTES =====- I'll add notes here if I need to.===== ERRORS =====- If you see an error in the video, please let me know and I will include it here.===== REFERENCES =====Note: the links are Amazon affiliate links. If you do happen to want to buy the book and use the link below, it helps me out a little.► Fundamentals of Aerodynamics, Andersonamzn.to/3emVuXU► Foundations of Aerodynamics, Kuethe and Chowamzn.to/2yMg1Vi► Theory of Wing Sections, Abbott and Doenhoffamzn.to/2wvZyUt
Source Panel Method: Normal Velocity Geometric Integral [I(ij)] JoshTheEngineer 2020-01-09 | In the previous video (Flow Around an Airfoil), we ended with an expression that still needed some simplification before we could use it to solve for the source panel strengths. In this video, we go through the solution process of that term, called the geometric integral (or at least that's what I'm calling it).Don't worry, we're almost ready to code our panel method. The next video is about creating the system of equations and solving it.===== RELEVANT VIDEOS =====► Panel Methods Playlistyoutube.com/watch?v=bWjo3N9COz4&list=PLxT-itJ3HGuUDVMuWKBxyoY8Dm9O9qstP► Panel Method Geometryyoutube.com/watch?v=kIqxbd937PI► Building More Complex Flowsyoutube.com/watch?v=EKzbwJvKcmw► Flow Around an Airfoilyoutube.com/watch?v=cLdv1UfX1g8===== NOTES =====- I'll add notes here if I need to.===== ERRORS =====- If you see an error in the video, please let me know and I will include it here.===== REFERENCES =====Note: the links are Amazon affiliate links. If you do happen to want to buy the book and use the link below, it helps me out a little.► Fundamentals of Aerodynamics, Andersonamzn.to/3emVuXU► Foundations of Aerodynamics, Kuethe and Chowamzn.to/2yMg1Vi► Theory of Wing Sections, Abbott and Doenhoffamzn.to/2wvZyUt
Flow Around an Airfoil: Panel Methods JoshTheEngineer 2020-01-03 | In the previous video (Building More Complex Flows), we ended with an equation for the velocity potential induced at an arbitrary point P in the flowfield, due to a uniform flow and all of the source panels that approximate our airfoil shape.In this video, we dictate a boundary condition that forces the airfoil to be a streamline of the flow, allowing us to solve for the unknowns in the velocity potential equation (all the source panel strengths). We also dictate the other boundary condition that will allow us to calculate the velocity (and thus pressure coefficient) on the airfoil surface.===== RELEVANT VIDEOS =====► Panel Methods Playlistyoutube.com/watch?v=bWjo3N9COz4&list=PLxT-itJ3HGuUDVMuWKBxyoY8Dm9O9qstP► Panel Method Geometryyoutube.com/watch?v=kIqxbd937PI► Building More Complex Flowsyoutube.com/watch?v=EKzbwJvKcmw===== NOTES =====- As shown in the text in my video at 12:32, the boundary point indices (k and k+1) are reversed. This has no implication on the derivation, but just note that the tangential vector always points from point k to point k+1.===== ERRORS =====- If you see an error in the video, please let me know and I will include it here.===== REFERENCES =====Note: the links are Amazon affiliate links. If you do happen to want to buy the book and use the link below, it helps me out a little.► Fundamentals of Aerodynamics, Andersonamzn.to/3emVuXU► Foundations of Aerodynamics, Kuethe and Chowamzn.to/2yMg1Vi► Theory of Wing Sections, Abbott and Doenhoffamzn.to/2wvZyUt
Building More Complex Potential Flows (Panel Methods) JoshTheEngineer 2019-12-07 | We've gone through the elementary incompressible potential flows (uniform flow, source/sink flow, and vortex flow) in previous videos. Now we can build up a more complex flow step by step, using different variations of sources: single source, two sources, many sources, continuous curve of infinite sources, etc.The final equation in this video shows the velocity potential induced at an arbitrary point P in the flowfield due to a uniform flow and N source panels. The next video will go through how we can use this equation to solve for the source panel strengths that will result in a physical flow around our airfoil.===== RELEVANT VIDEOS =====► Panel Methods Playlistyoutube.com/watch?v=bWjo3N9COz4&list=PLxT-itJ3HGuUDVMuWKBxyoY8Dm9O9qstP► Source/Sink Flowyoutube.com/watch?v=eLDI_jV3yo0► Uniform Flowyoutube.com/watch?v=jCTTDclJZEk► Uniform + Source/Sink Flowyoutube.com/watch?v=zIvpN9f9dAA===== NOTES =====- Notes will be included here.===== ERRORS =====- Let me know if you see any errors and I will include them here.===== REFERENCES =====Note: the links are Amazon affiliate links. If you do happen to want to buy the book and use the link below, it helps me out a little.► Fundamentals of Aerodynamics, Andersonamzn.to/3emVuXU► Foundations of Aerodynamics, Kuethe and Chowamzn.to/2yMg1Vi► Theory of Wing Sections, Abbott and Doenhoffamzn.to/2wvZyUt
How To Take Pictures Like NASA: DIY Background Oriented Schlieren JoshTheEngineer 2019-10-21 | Want to take schlieren images or videos at home, but don't have access to a nice mirror? Or you've mastered the conventional schlieren technique and want to try your hand at something a little different? Or like the title mentions, do you want to take schlieren images like NASA? In this video, I'll walk you through every step you need to get started with Background Oriented Schlieren (BOS) experiments in your own home. Everything can be done with programs that are free to use. I also include my specially-written Python and MATLAB GUI programs for you to use.UPDATED: Please use the second version (v2) of my ImageJ macro so you don't run into any issues. Here is my update YouTube video: youtube.com/watch?v=GXapOtBf52o==== TIME-STAMPS ====00:00 - Introduction01:25 - Outline02:32 - Programs you will need03:08 - FFmpeg05:28 - ImageJ/Fiji13:42 - ImageJ macros16:39 - Python code (images)23:38 - MATLAB code (images and videos)36:05 - DIY at home==== NOTES ====► This is a long video, I know. But I would rather upload a long, comprehensive video than skimp on the details. But if you're a regular to my channel, you probably know that already.► My programs are not completely fool-proof. If you do something horribly wrong, you might get an error. But, if you use it the way I walk you through in the video, you shouldn't have any issues. If you do get an error, it might be best to just restart the program.► I will probably be adding the video capability to the Python GUI at some point. Or better yet, you can fork the repository on GitHub and practice your Python coding by adding it in yourself.► Not every video you download from YouTube will work when trying to convert it like I did with FFmpeg. Most of the ones I tried worked, but if yours doesn't, I'm not the best person to ask how to fix it. Google is helpful here.► The NASA data obviously looks really nice. My processing of their data doesn't look as nice. There are many reasons for this, including (but not limited to) the high quality of their raw images, averaging multiple images together, using a more sophisticated code, and using a different analysis technique (optical flow).==== RELEVANT VIDEOS ====Schlieren YouTube Playlist► youtube.com/watch?v=GEImPtOM-d4&list=PLxT-itJ3HGuWift1-NXVhSCzGd9uqDJv1==== RELEVANT LINKS ====My website with code and PDF document► http://www.joshtheengineer.com/2019/10/20/how-to-take-pictures-like-nasa-using-background-oriented-schlieren-bosMy GitHub with code► github.com/jte0419/Background_Oriented_Schlieren==== REFERENCES ====Python's "normxcorr2" function from GitHub user Sabrewarrior→ github.com/Sabrewarrior/normxcorr2-pythonNASA AirBOS Shock Wave Video→ youtube.com/watch?v=443RLEnu_UIFind all the rest of my references in my PDF document
Panel Method Geometry JoshTheEngineer 2019-10-09 | This is the first real step towards writing a panel code: the geometry. While the material in this video might seem trivial at first, it can actually be the most confusing part of the whole method since it involves a lot of tedious definitions of variables. If these variables aren't defined properly in your code, you'll get results that don't make sense.In this video, I'll go through the panel method geometry in detail. We will use the simplest geometry, a circle approximated with 8 points (octagon), to define the variables. Then we will look at the Python code I wrote for both the circle and an airfoil. You can find the links to my Python and MATLAB programs in the CODE section below.==== CODE =====Panel Method Blog Post and Code (Python and MATLAB)- Code can be downloaded at the bottom of the post► http://www.joshtheengineer.com/2019/10/09/panel-method-geometryGitHub: Panel Methods► github.com/jte0419/Panel_Methods==== RELATED VIDEOS/PLAYLISTS ====Panel Methods YouTube Playlist► youtube.com/playlist?list=PLxT-itJ3HGuUDVMuWKBxyoY8Dm9O9qstPPanel Methods Overview Launch Page► http://www.joshtheengineer.com/panel-methods==== ERRORS ====- If you find errors in the video, let me know and I'll add them here.===== REFERENCES =====Note: the links are Amazon affiliate links. If you do happen to want to buy the book and use the link below, it helps me out a little.► Fundamentals of Aerodynamics, Andersonamzn.to/3emVuXU► Foundations of Aerodynamics, Kuethe and Chowamzn.to/2yMg1Vi► Theory of Wing Sections, Abbott and Doenhoffamzn.to/2wvZyUt
Uniform + Vortex Flow (Incompressible Potential Flow) JoshTheEngineer 2019-08-25 | This is the last of the elementary flow videos, and here we will combine uniform flow with vortex flow. After showing the Cartesian velocity components on the board, we will go through a script to compute the combined flow-field and calculate the circulation around some arbitrary curves.==== RELEVANT VIDEOS ====Incompressible Potential Flow- youtube.com/watch?v=Zo5XIcX8s2QUniform Flow- youtube.com/watch?v=jCTTDclJZEkSource/Sink Flow- youtube.com/watch?v=eLDI_jV3yo0Uniform + Source/Sink Flow- youtube.com/watch?v=zIvpN9f9dAAVortex Flow- youtube.com/watch?v=61jvr3rtmLE==== RELEVANT LINKS ====Blog post about incompressible potential flow► http://www.joshtheengineer.com/2019/05/05/introduction-to-incompressible-potential-flowBlog and code for combined uniform and vortex flow► http://www.joshtheengineer.com/2019/08/25/combined-flow-uniform-and-vortex-flowGitHub: Panel Methods► github.com/jte0419/Panel_Methods===== REFERENCES =====Note: the links are Amazon affiliate links. If you do happen to want to buy the book and use the link below, it helps me out a little.► Fundamentals of Aerodynamics, Andersonamzn.to/3emVuXU► Foundations of Aerodynamics, Kuethe and Chowamzn.to/2yMg1Vi► Theory of Wing Sections, Abbott and Doenhoffamzn.to/2wvZyUt► Fundamental Mechanics of Fluids, Currieamzn.to/2RpX2q4► Elements of Gasdynamics, Liepmann and Roshkoamzn.to/2XrZjoo
Vortex Flow (Incompressible Potential Flow) JoshTheEngineer 2019-08-25 | In this video, we will start with the velocity potential for vortex flow, and compute the Cartesian velocity components. Then we will go through a script to compute the flow-field due to this vortex, along with the circulation around a closed curve.==== ERRORS ====- On the whiteboard from 6:16 to 6:58, the "V_theta" partial derivative should have a "del theta" in the denominator instead of a "del r". This is incorrect in the first and second expressions, but correct in the third expression (right before the boxed equation).==== RELEVANT VIDEOS ====Incompressible Potential Flow- youtube.com/watch?v=Zo5XIcX8s2QUniform Flow- youtube.com/watch?v=jCTTDclJZEkSource/Sink Flow- youtube.com/watch?v=eLDI_jV3yo0Uniform + Source/Sink Flow- youtube.com/watch?v=zIvpN9f9dAAUniform + Vortex Flow- youtube.com/watch?v=SoMuRp5v16w==== RELEVANT LINKS ====Blog post about incompressible potential flow► http://www.joshtheengineer.com/2019/05/05/introduction-to-incompressible-potential-flowBlog and code for combined uniform and vortex flow► http://www.joshtheengineer.com/2019/08/25/elementary-flow-vortex-flowGitHub: Panel Methods► github.com/jte0419/Panel_Methods===== REFERENCES =====Note: the links are Amazon affiliate links. If you do happen to want to buy the book and use the link below, it helps me out a little.► Fundamentals of Aerodynamics, Andersonamzn.to/3emVuXU► Foundations of Aerodynamics, Kuethe and Chowamzn.to/2yMg1Vi► Theory of Wing Sections, Abbott and Doenhoffamzn.to/2wvZyUt► Fundamental Mechanics of Fluids, Currieamzn.to/2RpX2q4► Elements of Gasdynamics, Liepmann and Roshkoamzn.to/2XrZjoo
Uniform + Source/Sink Flow (Incompressible Potential Flow) JoshTheEngineer 2019-08-25 | Here we will combine the previous two elementary flows: uniform and source/sink flow (links below). After showing the Cartesian velocity components on the board, we will go through a script to compute the combined flow-field and calculate the circulation around an arbitrary curve.==== RELEVANT VIDEOS ====Incompressible Potential Flow- youtube.com/watch?v=Zo5XIcX8s2QUniform Flow- youtube.com/watch?v=jCTTDclJZEkSource/Sink Flow- youtube.com/watch?v=eLDI_jV3yo0Vortex Flow- youtube.com/watch?v=61jvr3rtmLEUniform + Vortex Flow- youtube.com/watch?v=SoMuRp5v16w==== RELEVANT LINKS ====Blog post about incompressible potential flow► http://www.joshtheengineer.com/2019/05/05/introduction-to-incompressible-potential-flowBlog and code for combined uniform and source/sink flow► http://www.joshtheengineer.com/2019/08/25/combined-flow-uniform-and-source-flowGitHub: Panel Methods► github.com/jte0419/Panel_Methods===== REFERENCES =====Note: the links are Amazon affiliate links. If you do happen to want to buy the book and use the link below, it helps me out a little.► Fundamentals of Aerodynamics, Andersonamzn.to/3emVuXU► Foundations of Aerodynamics, Kuethe and Chowamzn.to/2yMg1Vi► Theory of Wing Sections, Abbott and Doenhoffamzn.to/2wvZyUt► Fundamental Mechanics of Fluids, Currieamzn.to/2RpX2q4► Elements of Gasdynamics, Liepmann and Roshkoamzn.to/2XrZjoo
Source/Sink Flow (Incompressible Potential Flow) JoshTheEngineer 2019-08-25 | This is the next elementary flow after uniform flow. We will start with the velocity potential (without derivation), and then compute the Cartesian velocity components. We will then go through a script to compute the flow-field due to a source/sink, and compute the circulation around an arbitrary curve.==== RELEVANT VIDEOS ====Incompressible Potential Flow- youtube.com/watch?v=Zo5XIcX8s2QUniform Flow- youtube.com/watch?v=jCTTDclJZEkUniform + Source/Sink Flow- youtube.com/watch?v=zIvpN9f9dAAVortex Flow- youtube.com/watch?v=61jvr3rtmLEUniform + Vortex Flow- youtube.com/watch?v=SoMuRp5v16w==== RELEVANT LINKS ====Blog post about incompressible potential flow► http://www.joshtheengineer.com/2019/05/05/introduction-to-incompressible-potential-flowBlog and code for source/sink flow► http://www.joshtheengineer.com/2019/08/25/elementary-flow-source-sink-flowGitHub: Panel Methods► github.com/jte0419/Panel_Methods===== REFERENCES =====Note: the links are Amazon affiliate links. If you do happen to want to buy the book and use the link below, it helps me out a little.► Fundamentals of Aerodynamics, Andersonamzn.to/3emVuXU► Foundations of Aerodynamics, Kuethe and Chowamzn.to/2yMg1Vi► Theory of Wing Sections, Abbott and Doenhoffamzn.to/2wvZyUt► Fundamental Mechanics of Fluids, Currieamzn.to/2RpX2q4► Elements of Gasdynamics, Liepmann and Roshkoamzn.to/2XrZjoo
Uniform Flow (Incompressible Potential Flow) JoshTheEngineer 2019-08-25 | This is the simplest of the elementary potential flows. We will start with an arbitrary freestream velocity, derive the velocity potential, and then verify the original velocity. Using the Cartesian velocity X and Y components, we will code up a simple script for the flow-field in a uniform flow, and compute the circulation around an arbitrary curve.==== RELEVANT VIDEOS ====Incompressible Potential Flow- youtube.com/watch?v=Zo5XIcX8s2QSource/Sink Flow- youtube.com/watch?v=eLDI_jV3yo0Uniform + Source/Sink Flow- youtube.com/watch?v=zIvpN9f9dAAVortex Flow- youtube.com/watch?v=61jvr3rtmLEUniform + Vortex Flow- youtube.com/watch?v=SoMuRp5v16w==== RELEVANT LINKS ====Blog post about incompressible potential flow► http://www.joshtheengineer.com/2019/05/05/introduction-to-incompressible-potential-flowBlog and code for uniform flow► http://www.joshtheengineer.com/2019/08/25/elementary-flow-uniform-flowGitHub: Panel Methods► github.com/jte0419/Panel_Methods===== REFERENCES =====Note: the links are Amazon affiliate links. If you do happen to want to buy the book and use the link below, it helps me out a little.► Fundamentals of Aerodynamics, Andersonamzn.to/3emVuXU► Foundations of Aerodynamics, Kuethe and Chowamzn.to/2yMg1Vi► Theory of Wing Sections, Abbott and Doenhoffamzn.to/2wvZyUt► Fundamental Mechanics of Fluids, Currieamzn.to/2RpX2q4► Elements of Gasdynamics, Liepmann and Roshkoamzn.to/2XrZjoo
Incompressible Potential Flow Overview JoshTheEngineer 2019-05-05 | This video is a brief introduction to incompressible potential flows. We first obtain the velocity as a function of a scalar potential field (the velocity potential). Then we use the mass conservation equation along with the velocity we found to obtain the equation that governs incompressible potential flow, Laplace's equation.Because Laplace's equation is linear, the sum of solutions to the equation is still a solution. The power of this result will become clearer when we start to build more complicated flows from what are called "elementary flows", which I will go through in the next video.==== RELEVANT VIDEOS ====Curl of the Gradient of a Scalar Field is Zero- youtube.com/watch?v=A5WYHY8qhe8Coming soon: elementary flow videos including- Uniform Flow- Source/Sink Flow- Combined Uniform + Source/Sink Flow- Vortex Flow- Combined Uniform + Vortex Flow==== RELEVANT LINKS ====Blog post about incompressible potential flow- http://www.joshtheengineer.com/2019/05/05/introduction-to-incompressible-potential-flowGitHub: Panel Methods► github.com/jte0419/Panel_Methods==== REFERENCES ====Fundamentals of Aerodynamics, Anderson► Chapter 2.15+ (5th edition), Chapter 3.6+Fundamental Mechanics of Fluids, Currie► Pg. 63+ (2nd edition), works with complex variablesFoundations of Aerodynamics, Kuethe and Chow►Chapter 2.11+ for incompressible, Chapter 7.3 for compressible (3rd edition)Elements of Gasdynamics, Liepmann and Roshko►Pg. 196+, works in index notationTheory of Wing Sections, Abbott and Doenhoff►Chapter 2 (pg. 31+)
How To: Calculate Circulation JoshTheEngineer 2019-04-01 | In this video, we will compute the circulation around an ellipse for an arbitrary vector field using MATLAB and Python. First we will look at the equation for circulation, and then transform it into a useful form for its calculation using a discrete vector field. Finally, we will run some code that computes the circulation for an arbitrary vector field in both MATLAB and Python.The purpose of this code is to be able to compute the circulation, and thus the lift per unit span, of an airfoil in my future vortex panel method video/code. I will also be using it in my potential flow elementary solutions videos.===== ERRORS =====► The angle definitions in the MATLAB code shown in the video are incorrect. The Python version was always correct, but I was using an old version of the MATLAB code in the video by accident. The code available on my website has been updated as of 08/19/19, and both Python and MATLAB functions are correct now.► The error is that you do in fact need a duplicate angle in order to finish the line integral around the ellipse. Without the duplicate angle, it leaves the integrated ellipse open. Including the duplicate angle ensures that the entire ellipse is integrated over (i.e. a closed curve).===== RELEVANT LINKS =====MATLAB and Python code from my website► http://www.joshtheengineer.com/2019/04/01/compute-circulation-of-a-vector-field-in-matlab-and-pythonGitHub: Panel Methods► github.com/jte0419/Panel_Methods===== NOTES =====► I'm using the circulation defined in Anderson's "Fundamentals of Aerodynamics".► You can use any other shape you want for the closed curve, but the ellipse is useful for my purposes.
Load Airfoil Coordinates using MATLAB JoshTheEngineer 2019-03-31 | In a previous video, we downloaded the entire airfoil database from the UIUC Airfoil Database (https://m-selig.ae.illinois.edu/ads/coord_database.html) using a simple Python script. In this video, I will go through a function in MATLAB that allows you to read in any of the airfoils. I also show how to get and save the airfoils from the Selig-format archived database, along with a simplified MATLAB function that also works well.===== RELEVANT LINKS =====► MATLAB script and functions from this videohttp://www.joshtheengineer.com/2019/03/30/load-airfoil-data-into-matlab► Python code to download UIUC airfoil databasehttp://www.joshtheengineer.com/2019/01/30/uiuc-airfoil-database-file-downloadGitHub: Panel Methods► github.com/jte0419/Panel_Methods===== RELEVANT VIDEOS =====UIUC Airfoil Database Download Python Code→ http://bit.ly/2I0zvIl===== NOTES =====► There are other ways to load these airfoil data files, this is just my take on it.
UIUC Airfoil Database: Download All Files using Python JoshTheEngineer 2019-01-31 | This video shows how to write a Python script to download all the airfoil files from the UIUC Airfoil Database. The link to the database is the following:https://m-selig.ae.illinois.edu/ads/coord_database.htmlI'll be using these airfoil files in my future Source Panel Method and Vortex Panel Method videos. I'm using Python because it's easy to scrape data from websites. Once you get all the files once, you won't need to do it again.===== RELEVANT LINKS =====► You can download the Python code from my websitehttp://www.joshtheengineer.com/2019/01/30/uiuc-airfoil-database-file-download► Anaconda Navigator Downloadanaconda.com/distributionGitHub: Panel Methods► github.com/jte0419/Panel_Methods===== RELEVANT VIDEOS =====How To: Run XFoil from MATLAB→ youtube.com/watch?v=bWjo3N9COz4Load Airfoil Coordinates from UIUC Files into MATLAB→ Coming soon!Panel Method Motivation and Introduction→ Coming soon!Panel Method Geometry Definitions→ Coming soon!Source Panel Derivation and Coding→ Coming soon!Vortex Panel Derivation and Coding→ Coming soon!===== NOTES =====► This code used in this video downloads all the files from the main page of the database. In my next video on how to load these airfoil files in MATLAB, I show how it might be easier to download all the Selig file formats instead. The code for that can also be found at the link above for the Python code.► I'm not an expert at Python. I'm still learning. The code might not be the most efficient way to do something, but it works, and that's all I care about for now.► Thanks to Dr. Selig for giving me permission to scrape the database for every airfoil data file.
How To: Run XFoil from MATLAB JoshTheEngineer 2019-01-30 | This video shows how to run XFoil from a MATLAB script (for a Python script, see link below). This will come in handy for my future Vortex Panel Method video, where we will compare our pressure coefficient and lift coefficient results with the XFoil results. We'll go through three steps in this video.1) Run XFoil and output the files we need (airfoil coordinates and pressure coefficient)2) Load saved files from XFoil into MATLAB and view plots3) Run XFoil from the MATLAB script itself, and view plots===== RELEVANT LINKS =====► You can download the MATLAB script from my websitehttp://www.joshtheengineer.com/2019/01/30/running-xfoil-from-matlab► Do you want to run XFoil from Python instead? Download the script from my websitehttp://www.joshtheengineer.com/2019/02/06/running-xfoil-from-python► Download XFoilhttps://web.mit.edu/drela/Public/web/xfoil/GitHub: Panel Methods► github.com/jte0419/Panel_Methods===== RELEVANT VIDEOS =====UIUC Airfoil Database Download Python Code→ youtube.com/watch?v=nILo18DlqAoLoad Airfoil Coordinates from UIUC Files into MATLAB→ youtube.com/watch?v=xJYxMfGFrk8Panel Method Motivation and Introduction→ Coming soon!Panel Method Geometry Definitions→ Coming soon!Source Panel Derivation and Coding→ Coming soon!Vortex Panel Derivation and Coding→ Coming soon!===== NOTES =====► This is not a comprehensive XFoil user guide video. I'm only running the commands I need for my future Vortex Panel Method video.► If you just want the NACA 4-digit airfoil coordinates, you can also use my NACA 4-Digit Airfoil MATLAB code to generate them.
How To: Tapping 3D Printed Parts JoshTheEngineer 2018-04-22 | In this video I'll show you how I tap holes (cut threads) in my 3D printed parts.===== NOTES =====► The sizes of NPT fittings don't correspond to actual dimensions, so you'll note the 1/8 NPT doesn't have a diameter of 1/8". Keep that in mind when purchasing parts.► The clamp I used can also be purchased at Harbor Freight for a couple bucks.► As mentioned in the video, you can try printing the threads into your part, but I did it this way instead. The higher the threads-per-inch, the harder it will be to print the threads into your part.===== RELEVANT VIDEOS =====→ Monoprice MP Select Mini Intro/Reviewhttp://bit.ly/MPSelectMini→ How To: Level Your Printing Bedhttp://bit.ly/LevelTheBed===== RELEVANT LINKS =====►McMaster-Carrmcmaster.com/#► Harbor-Freight Tap and Die Setharborfreight.com/hand-tools/tap-die/40-pc-carbon-steel-sae-tap-and-die-set-62831.html► Carbide Depot: Tap Chart/Pipe Threadshttp://www.carbidedepot.com/formulas-tap-pipe.htm► Carbide Depot: Drill Size Charthttp://www.carbidedepot.com/formulas-drillsize.htm
CFD of Normal Shock in CD Nozzle using SU2 JoshTheEngineer 2018-04-17 | Let's run a CFD simulation of a normal shock in a converging-diverging (CD) nozzle! In this video, we will go through step-by-step how to set up the problem, run it, and analyze the solutions. Note that it would help to have watched the videos I list down in the Relevant Videos section.===== NOTES =====► I'm using the MARKER_FAR boundary condition to set the throat, or inlet, values. You can also use the MARKER_SUPERSONIC_INLET boundary condition and get the same results.► I'm not quite sure why the throat values are slightly off even though the solutions converged. Part of me thinks it has to do with the Mach number being set to 1 (or close to 1, since I've tried it with it slightly above 1 as well with the same results). The way that problems are solved when they are subsonic vs. supersonic changes, and since it's straddling that line, it might be difficult. Without looking at the numerics and spending too much time on this, it's hard for me to say. If you figure it out or have any comments/suggestions, let me know.===== RELEVANT LINKS =====► CFG and SU2 files used in this videohttp://www.joshtheengineer.com/2018/04/16/cfd-with-su2-normal-shock-in-cd-nozzle► NSN MATLAB codehttp://www.joshtheengineer.com/2018/01/24/normal-shock-in-converging-diverging-nozzle===== RELEVANT VIDEOS =====→ Converging-Diverging Nozzle Explainedhttp://bit.ly/CDNozzleExplained→ Pressure Ratio Delineationshttp://bit.ly/PressureDelineations→ Calculating Normal Shock in Nozzlehttp://bit.ly/CalculatingNSN→ Isentropic Supersonic CFD Simulationhttp://bit.ly/IsentropicSupersonic→ GMSH: Rocket Nozzle Meshhttp://bit.ly/GMSHRocketNozzle→ How To: Install SU2http://bit.ly/InstallSU2→ CFD Example in SU2http://bit.ly/SU2Example===== FREE SOFTWARE =====► SU2 Downloadsu2code.github.io/download.html► GMSH Downloadhttp://gmsh.info► Paraview Downloadparaview.org/download
Visualizing Formula 1 Engine Heat JoshTheEngineer 2018-04-08 | In this video, we will go through how to visualize small heat disturbances from the engine heat of a Formula 1 race car! I'm going to be using a video from Red Bull Racing back when they were promoting the COTA race, along with a MATLAB code called PIVLab (links to everything below).===== NOTES =====→ You can also skip the masking step and just vector validate afterwards, and that works pretty well too.→ If you do want to mask, make sure to mask both the A and B images, and you probably won't need to do any vector validation afterwards if you're careful. I went through it again doing this, and I got some nice results.→ I tried to see if there was a way to get rid of the mask when outputting the video, but I wasn't able to find a way to do this. If you figure it out, let me know. If that's not a feature, I might try to go into the code and put that option in myself.- Thanks again to Jenna and Wayne for their help, which took time away from our coveted Wednesday Ninja Warrior night.===== PIVLAB =====→ MATLAB File Exchangemathworks.com/matlabcentral/fileexchange/27659-pivlab-particle-image-velocimetry--piv--tool→ PIVLab Websitehttp://pivlab.blogspot.com→ William's YouTube videoyoutube.com/watch?v=Sp3Ounq07Qc&t=26s→ CitationsThielicke, W. and Stamhuis, E.J. (2014): PIVlab – Towards User-friendly, Affordable and Accurate Digital Particle Image Velocimetry in MATLAB. Journal of Open Research Software 2(1):e30, DOI: http://dx.doi.org/10.5334/jors.blThielicke, W. and Stamhuis, E. J. (2014): PIVlab - Time-Resolved Digital Particle Image Velocimetry Tool for MATLAB (version: X.XX modify this). http://dx.doi.org/10.6084/m9.figshare.1092508 Thielicke, W. (2014): The Flapping Flight of Birds - Analysis and Application. Phd thesis, Rijksuniversiteit Groningen. http://irs.ub.rug.nl/ppn/382783069===== ATTRIBUTION =====► Force India imageArtes Max, Flickrflickr.com/photos/105731165@N07flickr.com/photos/105731165@N07/25768805927License: creativecommons.org/licenses/by-sa/2.0► Red Bull Racing promotional videoAston Martin Red Bull Racingyoutube.com/watch?v=0tEHQJn_hxoTime: ~3:16 to 3:18
CFD Simulation of Isentropic Supersonic Nozzle in SU2 JoshTheEngineer 2018-04-01 | Let's run a CFD simulation of an ideal rocket nozzle using SU2! In this video, we will use the mesh we created in another video (links below) to run a simulation in SU2 of a rocket nozzle designed using the Method of Characteristics (MoC). As a check of the solution, we can compare the exit Mach number between the CFD and MoC solutions.Links to all the necessary videos and files can be found in the sections below.===== FILES TO DOWNLOAD =====► Mesh File and Configuration Filehttp://www.joshtheengineer.com/2018/04/01/cfd-with-su2-isentropic-supersonic-nozzle-flow===== RELEVANT VIDEOS =====► Download and Install SU2goo.gl/MxeL3X► How to Run SU2goo.gl/z5NDsh► Nozzle Mesh in GMSHhttp://bit.ly/RocketGMSHSU2
GMSH: Rocket Nozzle Mesh for SU2 JoshTheEngineer 2018-04-01 | In this video, we will go through all the steps for creating a rocket nozzle mesh for use in the CFD program SU2. Note that the design of the nozzle geometry is handled by my Method of Characteristics (MoC) MATLAB code.I will be using this exact mesh in some rocket nozzle simulations in my future videos, so stay tuned for those!If you don't have MATLAB, you can simply download the mesh (.su2 file) from the link below.===== NOTES =====The boundary condition marker names for this mesh are the following:- Inlet- Nozzle- Outlet- Symmetry===== RELEVANT VIDEOS =====→ How To: Install SU2goo.gl/U8xYM2→ How To: Run SU2 Code Start to Finishgoo.gl/z5NDsh→ More GMSH Tutorialsgoo.gl/BL8Fzn→ Isentropic Supersonic Nozzle SimulationPosting soon!===== RELEVANT LINKS =====► My GitHub Repositorygithub.com/jte0419/Rocket_Nozzle_Design► GEO and SU2 Files for Rocket Nozzlehttp://www.joshtheengineer.com/2018/04/01/cfd-with-su2-isentropic-supersonic-nozzle-flow
Misleading RS-25 Incredible Fact JoshTheEngineer 2018-03-27 | I came across a weird sentence in an "RS-25 Incredible Facts" document while searching for some information on the engines. In this video, we will see why I thought it was weird, and why the fact is phrased the way it is.===== TOO LONG DIDN'T WATCH =====► What they do:The document divides the exit velocity of the gases coming out of the nozzle by the ambient speed of sound at sea level.► Why it's misleading:When you compare a velocity to a speed of sound, it is generally taken as a Mach number, which relates the local velocity to the local speed of sound. The local speed of sound in this case would be the speed of sound at the exit plane of the nozzle, which is much higher than the speed of sound at sea level standard.► Why it's not incorrect:They don't actually say anything about a Mach number in the document. They also don't mention what speed of sound they're talking about. It's vague enough to be correct.► Why did I make a video about this?I'm not quite sure.===== NOTES =====→ I actually emailed Aerojet Rocketdyne asking where this number came from when I first read this document. To their credit, they emailed back very quickly and asked for more information about my question, but by that time I had already figured out where it came from. I ended up forgetting to email them back, but it was nice that they responded so quickly.===== RELEVANT LINKS =====► RS-25 Incredible Facts Documenthttp://www.rocket.com/files/aerojet/documents/Capabilities/PDFs/RS-25_incred_facts_update_3-25-16_cropped.pdf► VT Calculatorhttp://www.dept.aoe.vt.edu/~devenpor/aoe3114/calc.html► CEA Onlinecearun.grc.nasa.gov===== THUMBNAIL CREDIT =====NASA Image Galleryimages-assets.nasa.gov/image/9400164/9400164~orig.jpgNASA ID: 9400164 "Space Shuttle Project"
CFD Example in SU2: Start to Finish JoshTheEngineer 2018-03-01 | Let's run a CFD simulation from start to finish! In this video, we will be starting from a problem definition, and working our way to a full CFD solution. The problem we will be working through is that of a simple oblique shock. We have already solved this exact oblique shock example in one of my other videos (see link below).===== NOTES =====► You can mess around with the settings in the configuration file to see how it changes the solution. For example, you can get more well-defined shock by changing the way the convective fluxes are evaluated.===== FILES TO DOWNLOAD =====► Mesh File (.su2) and Configuration File (.cfg)http://www.joshtheengineer.com/2018/02/28/how-to-run-su2-start-to-finish===== RELEVANT VIDEOS =====→ Download and Install SU2goo.gl/KmkUgD→ Oblique Shock Examplegoo.gl/8yjUvy===== RELEVANT LINKS =====► SU2 Oblique Shock Test Casesu2code.github.io/tutorials/Inviscid_Wedge===== PROGRAMS I USE (ALL FREE) =====► SU2su2code.github.io► GMSHhttp://gmsh.info► Paraviewparaview.org► VirtualBoxvirtualbox.org/wiki/Downloads► Notepad++notepad-plus-plus.org===== REFERENCES =====→ The SU2 GitHub and website→ Matt MacLean for introducing me to SU2 along with his GMSH tutorial
How To: Install SU2 CFD Code in Linux JoshTheEngineer 2018-03-01 | Let's install the open-source CFD program SU2 on your computer. In this video, I go through step-by-step how to install the code on Linux. My computer runs Windows, but I have VirtualBox installed and running Ubuntu, which is where I'm downloading and installing SU2 (see links below). If you have problems installing, or if this method doesn't work for you, I'm probably not the person to ask how to fix it. I would recommend Googling your issue, which is what I do when I get stuck. Everything listed in the LINKS section below is free.===== NOTES =====► There are multiple ways to do what I do in the video. This video just shows you one of the methods.► The newest version of SU2 is now at 6.0 (Falcon).► I use version 4 for the video tutorials I'm making since I ran these simulations before version 5 or 6 were out. If you want to follow along with the exact same configuration files, download version 4. Configuration files might need to be slightly changed if you want to run in 5 or 6, since some options have been added or removed.► I don't think you actually need to add the "SU2_CFD" line in the .bashrc file, as I do in this video.► Apparently I like the word "currently".===== LINKS =====→ SU2 Main GitHub Sitesu2code.github.io→ SU2 Releases Pagegithub.com/su2code/SU2/releases→ Other SU2 Stuffgithub.com/su2code→ VirtualBoxvirtualbox.org/wiki/Downloads→ Paraviewparaview.org/download→ GMSHhttp://gmsh.info===== ALIASES =====► Add the following to your alias file, which is called .bash_aliases in my casen. = nautilus.lsl = ls -llsla = ls -lamaxwindow = resize -s 1000 1000===== KEYBOARD SHORTCUTS =====Alt + Tab → Switch between windowsWin + S → Open workspace viewArrow + Enter → Switch to other workspace===== LINUX TERMINAL COMMANDS =====cd = Change directoryls = List filesls -l = List files in an ordered listls -a = List files including hidden filesnano = Text editing program without leaving terminal (can also use gedit, nedit, etc.)
Oblique Shock Example Problem JoshTheEngineer 2018-02-18 | Let's work through an oblique shock (OS) example. In this video, we will go through four methods for solving OS problems.1) Derived equations2) Compressible flow tables (NACA 1135)3) VT calculator4) MATLAB functions===== RELEVANT VIDEOS =====→ Oblique Shock Derivationgoo.gl/xLYYYP→ Normal Shock Relations Derivationgoo.gl/Unvjey→ Normal Shock Examplegoo.gl/RBJtgV===== RELEVANT LINKS =====► VT Calculatorhttp://www.dept.aoe.vt.edu/~devenpor/aoe3114/calc.html► MATLAB Functionsgithub.com/jte0419/Compressible_Flow_Relations===== THUMBNAIL CREDIT =====By Settles1 (Own work) [CC BY-SA 4.0 (creativecommons.org/licenses/by-sa/4.0)], via Wikimedia Commons
Explained: Oblique Shock Relations Derivation JoshTheEngineer 2018-02-18 | In this video, we will derive the oblique shock (OS) relations. We will start from integral conservation equations, and derive expressions for the downstream Mach number, density ratio, velocity ratio, pressure ratio, and temperature ratio.===== RELEVANT VIDEOS =====→ Oblique Shock Examplegoo.gl/77hjcb→ Normal Shock Relations Derivationgoo.gl/Unvjey→ Normal Shock Examplegoo.gl/RBJtgV===== RELEVANT LINKS =====► Surface (Double) Integrals Explanationhttp://www.joshtheengineer.com/2017/01/02/surface-double-integrals► VT Calculatorhttp://www.dept.aoe.vt.edu/~devenpor/aoe3114/calc.html► MATLAB Functionsgithub.com/jte0419/Compressible_Flow_Relations===== THUMBNAIL CREDIT =====By Settles1 (Own work) [CC BY-SA 4.0 (creativecommons.org/licenses/by-sa/4.0)], via Wikimedia Commons
SpaceX Falcon Heavy: Sound Calculation JoshTheEngineer 2018-02-08 | Let's calculate how far away a photographer was standing from the Falcon Heavy launch site using the sound delay from the video! After watching Destin's recent SmarterEveryDay video titled "The Incredible Sounds of the Falcon Heavy Launch", I thought it would be a fun little example problem to calculate how far away the photographer was from the rocket using the sound from the video. We can also check this value using Google maps, since we know where he was standing and where the rocket was launched from.===== NOTES =====→ At 3:12 in my video, I say 12,000 to 13,000 kilometers, when obviously I mean meters (so 12 to 13 kilometers)===== TIMING FROM VIDEO =====Here's what I think the timing is from the video:► Launch start = 3:22► First sound = 3:37As mentioned at the end of my video, here are the times that I was using for my calculation for the boosters on the way down to land. Let me know if you think they are actually something different!► See first ignition = 6:13► Done landing = 6:31► Sonic booms = 6:47 or 6:48The difference between seeing the first ignition and the sonic booms would be the time used in the calculation.===== RELEVANT VIDEOS =====→ SmarterEveryDay Videogoo.gl/Ra9mdB→ Photographer Trevor Mahlmannhttp://photos.tmahlmann.com→ Speed of Sound Equation Derivationgoo.gl/txELT2===== THUMBNAIL CREDIT =====By SpaceX (Falcon Heavy Demo Mission) [CC0 or CC0], via Wikimedia Commons
Normal Shock Example Problem JoshTheEngineer 2018-01-11 | Let's work through a normal shock problem together! In this video, we will be using four different ways of solving a simple normal shock problem. The four different methods we will be using can be found below (along with links which can be found in the RELEVANT LINKS section)1) Equations derived in my Normal Shock Relations video2) Compressible flow tables (only valid when gamma = 1.4)3) Online VT Calculator4) MATLAB functions based on VT Calculator===== NOTES =====► At around 5:54, I point to 1.4 in the Mach number column when I'm talking about the fact that the tables only work for gamma equal to 1.4. That's just where my finger happened to land on the page, and has nothing to do with what I'm talking about at the moment.► I happened to pick a Mach number that had an entry in the table (method 2). If your Mach number isn't listed in the table, you'll have to interpolate between the two bounding Mach numbers. Check out my linear interpolation video in the links below. I also have a video on programming a linear interpolation solver on your graphing calculator, also in the links below.===== RELEVANT LINKS =====→ Normal Shock Relationsgoo.gl/8BaJDH→ Online VT Calculatorhttp://www.dept.aoe.vt.edu/~devenpor/aoe3114/calc.html→ MATLAB Functionsgithub.com/jte0419/Compressible_Flow_Relations→ Linear Interpolation Explainedgoo.gl/WACknt→ TI-83 Linear Interpolation Programgoo.gl/i6PoeN===== ATTRIBUTION =====For VT Calculator:Javascript by William J. Devenport, Department of Aerospace and Ocean Engineering, Virginia Tech.Last update 5th January 2014. Please send comments, questions, or suggestions to: William Devenport
Compressible Flow Relations MATLAB Functions JoshTheEngineer 2018-01-11 | In this video, I'll be showing you how to use some functions I've adapted for use in compressible flow calculations. The three MATLAB functions can be found on my GitHub and my website (see links below). The code is taken from the Compressible Aerodynamics Calculator, which can be found at the following link, and maintained by William J. Devenport of Virginia Tech:http://www.dept.aoe.vt.edu/~devenpor/aoe3114/calc.htmlI'm aware that there are other functions already out there that can do these calculations, but I didn't see a MATLAB function on the VT Calculator site. It's nice to have MATLAB functions so you can code up some more interesting problems, and you won't need to worry about always hard-coding normal shock relations, etc.The format of these functions should be pretty easy to understand. If not, don't hesitate to ask. If you find any errors, let me know and I'll fix them.===== RELEVANT LINKS =====→ GitHubgithub.com/jte0419/Compressible_Flow_Relations→ My WebsitePost coming soon.===== ATTRIBUTION =====From the bottom of the website:Javascript by William J. Devenport, Department of Aerospace and Ocean Engineering, Virginia Tech.Last update 5th January 2014. Please send comments, questions, or suggestions to: William DevenportFanno Flow and Rayleigh Flow calculators by Adam Ford, included 7th February 2008.Conical flow calculator by Stephen Krauss, included 5th January 2014.
Converging-Diverging Nozzle Pressure Delineations JoshTheEngineer 2017-12-14 | In my converging-diverging (CD) nozzle video (link below), we saw that there were seven different flow conditions in a nozzle. If know what exit-to-reservoir pressure ratio our engine is operating at (see notes below), then we can define what condition our nozzle is operating at based on three pre-computed pressure ratios:1) Choked Isentropic Subsonic2) Normal Shock at Nozzle Exit3) Choked Isentropic SupersonicIn this video, we will compute the pressure ratios needed to obtain the three states listed above for a given nozzle area ratio (Ae/At).===== NOTES =====→ In this video, we can say that At = A* for each case because the flow is choked, and we do have sonic flow at the throat.→ We generally know the exit-to-reservoir pressure ratio that our engine is operating at. For instance, if we are analyzing the Space Shuttle Main Engine (RS-25) on the launchpad, then we know the exit pressure is approximately 101.325 kPa. We also know from the engine's specifications that the reservoir (or chamber) pressure is approximately 20.64 MPa. Dividing the two appropriately gives the pressure ratio we are looking for.===== RELEVANT LINKS=====→ Blog Post - Converging-Diverging Nozzle Pressure Delineationshttp://www.joshtheengineer.com/2017/12/17/converging-diverging-nozzle-pressure-delineations→ Solving the Area-Mach Number Relationhttp://www.joshtheengineer.com/2016/11/16/solving-the-area-mach-number-relation→ CD Nozzle MATLAB Code - GitHubgithub.com/jte0419/Converging_Diverging_Nozzle→ Compressible Flow Relations Code - GitHubgithub.com/jte0419/Compressible_Flow_Relations===== RELEVANT VIDEOS =====→ Explained: Converging Diverging Nozzlegoo.gl/7MBSck→ Area-Mach Number Relation [CPG]goo.gl/t8QE9T→ Normal Shock Relationsgoo.gl/Bvv2jj→ Stagnation Relationsgoo.gl/yrT9D4===== REFERENCES =====► Modern Compressible Flow, Anderson► Gas Dynamics, Volume 1, Zucrow and Hoffman► Elements of Gasdynamics, Liepmann and Roshko
