![[CFD] When and Why do I need Operating Pressure, Temperature and Density? @fluidmechanics101](https://i.ytimg.com/vi/zFDDhXEsIZ4/maxresdefault.jpg)
Uploaded November 2018 | Updated September 2026, 1 week ago
An introduction to the concepts of operating pressure, temperature and density, as they are used in CFD. Short, concise arguments are presented for why CFD codes use them, and when you should apply them. The following topics are covered:
1) 0:42 When and why do I need an operating pressure?
2) 12:59 When and why do I need an operating density?
3) 17:31 When and why do I need an operating temperature?
#cfd #operatingpressure #idealgaslaw
====================================================
Some useful references:
1) ANSYS FLUENT User Manual
8.14.3 Operating Pressure
sharcnet.ca/Software/Fluent6/html/ug/node374.htm
2) ANSYS CFX User Manual
1.2.8 Setting a reference pressure
sharcnet.ca/Software/Ansys/16.2.3/en-us/help/cfx_mod/i1298632.html
============================================
Want to learn more?
============================================
Grab a copy of my CFD Fundamentals Course (for beginners):
udemy.com/course/computational-fluid-dynamics-fundamentals-course/?referralCode=F9CF2DFFCA224E93834E
Learn how to write your own CFD code in MATLAB and python (for intermediates):
dr-aidan-wimshurst-s-school.teachable.com/p/the-simple-algorithm
Learn how I draw my figures and diagrams in Inkscape (for everyone):
dr-aidan-wimshurst-s-school.teachable.com/p/inkscape-for-scientists-and-engineers
============================================
Did you like the video?
============================================
Download the lecture slides from my website:
fluidmechanics101.com/pages/lectures.html
Buy me a coffee to say thanks:
buymeacoffee.com/NKEZrhvg0
Support the channel on Patreon (and get useful extras for your CFD studies):
patreon.com/fluidmechanics101
============================================
Donations:
============================================
1) PayPal
paypal.me/fluidmechanics101
==================================
Disclaimer
==================================
The methods, algorithms, equations, formulae, diagrams and explanations in this talk are for educational and demonstrative purposes only. They should never be used to analyse, design, accredit or validate real scientific / engineering / mathematical structures and flow systems. For such applications, appropriate trained, qualified and accredited (SQEP) engineers / scientists should be consulted along with the appropriate documentation, procedures and engineering standards. Furthermore, the information contained within this talk has not been verified, peer reviewed or checked in any way and is likely to contain several errors. It is therefore not appropriate to use this talk itself (or any of the algorithms, equations, formulae, diagrams and explanations contained within this talk) as an academic or technical reference. The reader should consult the original references and follow the verification and validation processes adopted by your company / institution when carrying out engineering calculations and analyses. Fluid Mechanics 101 and Dr. Aidan Wimshurst are not accountable or liable in any form for the use or misuse of the information contained in this talk beyond the specific educational and demonstrative purposes for which it was intended.
An introduction to the concepts of operating pressure, temperature and density, as they are used in CFD. Short, concise arguments are presented for why CFD codes use them, and when you should apply them. The following topics are covered:
1) 0:42 When and why do I need an operating pressure?
2) 12:59 When and why do I need an operating density?
3) 17:31 When and why do I need an operating temperature?
#cfd #operatingpressure #idealgaslaw
====================================================
Some useful references:
1) ANSYS FLUENT User Manual
8.14.3 Operating Pressure
sharcnet.ca/Software/Fluent6/html/ug/node374.htm
2) ANSYS CFX User Manual
1.2.8 Setting a reference pressure
sharcnet.ca/Software/Ansys/16.2.3/en-us/help/cfx_mod/i1298632.html
============================================
Want to learn more?
============================================
Grab a copy of my CFD Fundamentals Course (for beginners):
udemy.com/course/computational-fluid-dynamics-fundamentals-course/?referralCode=F9CF2DFFCA224E93834E
Learn how to write your own CFD code in MATLAB and python (for intermediates):
dr-aidan-wimshurst-s-school.teachable.com/p/the-simple-algorithm
Learn how I draw my figures and diagrams in Inkscape (for everyone):
dr-aidan-wimshurst-s-school.teachable.com/p/inkscape-for-scientists-and-engineers
============================================
Did you like the video?
============================================
Download the lecture slides from my website:
fluidmechanics101.com/pages/lectures.html
Buy me a coffee to say thanks:
buymeacoffee.com/NKEZrhvg0
Support the channel on Patreon (and get useful extras for your CFD studies):
patreon.com/fluidmechanics101
============================================
Donations:
============================================
1) PayPal
paypal.me/fluidmechanics101
==================================
Disclaimer
==================================
The methods, algorithms, equations, formulae, diagrams and explanations in this talk are for educational and demonstrative purposes only. They should never be used to analyse, design, accredit or validate real scientific / engineering / mathematical structures and flow systems. For such applications, appropriate trained, qualified and accredited (SQEP) engineers / scientists should be consulted along with the appropriate documentation, procedures and engineering standards. Furthermore, the information contained within this talk has not been verified, peer reviewed or checked in any way and is likely to contain several errors. It is therefore not appropriate to use this talk itself (or any of the algorithms, equations, formulae, diagrams and explanations contained within this talk) as an academic or technical reference. The reader should consult the original references and follow the verification and validation processes adopted by your company / institution when carrying out engineering calculations and analyses. Fluid Mechanics 101 and Dr. Aidan Wimshurst are not accountable or liable in any form for the use or misuse of the information contained in this talk beyond the specific educational and demonstrative purposes for which it was intended.
![[CFD] When and Why do I need Operating Pressure, Temperature and Density?](https://i.ytimg.com/vi/zFDDhXEsIZ4/mqdefault.jpg "[CFD] When and Why do I need Operating Pressure, Temperature and Density?
An introduction to the concepts of operating pressure, temperature and density, as they are used in CFD. Short, concise arguments are presented for why CFD codes use them, and when you should apply them. The following topics are covered:
1) 0:42 When and why do I need an operating pressure?
2) 12:59 When and why do I need an operating density?
3) 17:31 When and why do I need an operating temperature?
#cfd #operatingpressure #idealgaslaw
Some useful references:
1) ANSYS FLUENT User Manual
8.14.3 Operating Pressure
https://www.sharcnet.ca/Software/Fluent6/html/ug/node374.htm
2) ANSYS CFX User Manual
1.2.8 Setting a reference pressure
https://www.sharcnet.ca/Software/Ansys/16.2.3/en-us/help/cfx_mod/i1298632.html
Want to learn more?
Grab a copy of my CFD Fundamentals Course (for beginners):
https://www.udemy.com/course/computational-fluid-dynamics-fundamentals-course/?referralCode=F9CF2DFFCA224E93834E
Learn how to write your own CFD code in MATLAB and python (for intermediates):
https://dr-aidan-wimshurst-s-school.teachable.com/p/the-simple-algorithm
Learn how I draw my figures and diagrams in Inkscape (for everyone):
https://dr-aidan-wimshurst-s-school.teachable.com/p/inkscape-for-scientists-and-engineers
Did you like the video?
Download the lecture slides from my website:
https://www.fluidmechanics101.com/pages/lectures.html
Buy me a coffee to say thanks:
https://www.buymeacoffee.com/NKEZrhvg0
Support the channel on Patreon (and get useful extras for your CFD studies):
https://www.patreon.com/fluidmechanics101
Donations:
1) PayPal
https://www.paypal.me/fluidmechanics101
Disclaimer
The methods, algorithms, equations, formulae, diagrams and explanations in this talk are for educational and demonstrative purposes only. They should never be used to analyse, design, accredit or validate real scientific / engineering / mathematical structures and flow systems. For such applications, appropriate trained, qualified and accredited (SQEP) engineers / scientists should be consulted along with the appropriate documentation, procedures and engineering standards. Furthermore, the information contained within this talk has not been verified, peer reviewed or checked in any way and is likely to contain several errors. It is therefore not appropriate to use this talk itself (or any of the algorithms, equations, formulae, diagrams and explanations contained within this talk) as an academic or technical reference. The reader should consult the original references and follow the verification and validation processes adopted by your company / institution when carrying out engineering calculations and analyses. Fluid Mechanics 101 and Dr. Aidan Wimshurst are not accountable or liable in any form for the use or misuse of the information contained in this talk beyond the specific educational and demonstrative purposes for which it was intended.")
![[CFD] What Wall Functions Do I Need for Turbulent Kinetic Energy?](https://i.ytimg.com/vi/zSIgKsQSa9k/mqdefault.jpg "[CFD] What Wall Functions Do I Need for Turbulent Kinetic Energy?
[CFD] What Wall Functions Do I Need for Turbulent Kinetic Energy?
An introduction to the wall functions that are used to capture the near wall behaviour of the turbulent kinetic energy (k) in all mainstream CFD codes (OpenFOAM, Fluent, CFX, Star). The following topics are covered:
1) 2:11 How do we modify the production and dissipation of k in the wall adjacent cell?
2) 13:33 Why do some CFD codes specify dk/dn at the wall?
3) 22:12 Why do some CFD codes specify k directly at the cell centroid?
#wallfunctions #tke #kwallfunction
Some useful references:
1) ANSYS FLUENT User Manual
12.10.2 Standard Wall Functions
http://www.afs.enea.it/project/neptunius/docs/fluent/html/th/node99.htm
2) G. Kalitzin, G. Medic, G. Iaccarino and P. Durbin
Near-wall behaviour of RANS turbulene models and implications for wall functions
Journal of Computational Physics 204 (2005) 265-291
http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.584.2507&rep=rep1&type=pdf
3) Moser, Kim & Mansour, Direct numerical simulation of turbulent channel flow up to Re_tau = 590. Physics of Fluids, 11(4), 1999.
https://cfd.spbstu.ru/agarbaruk/doc/1999_Moser-Kim-Mansour_Direct-numerical-simulation-of-turbulent-channel-flow-up-to-Re-590.pdf
4) The complete set of statistical DNS data for turbulent channel flow:
http://turbulence.ices.utexas.edu/MKM_1999.html
5) J. Bredberg. On the wall boundary condition for turbulence models. Internal report 00/4, Chalmers University of Technology, Sweden, 2000.
http://www.tfd.chalmers.se/~lada/postscript_files/jonas_report_WF.pdf
Want to learn more?
Grab a copy of my CFD Fundamentals Course (for beginners):
https://www.udemy.com/course/computational-fluid-dynamics-fundamentals-course/?referralCode=F9CF2DFFCA224E93834E
Learn how to write your own CFD code in MATLAB and python (for intermediates):
https://dr-aidan-wimshurst-s-school.teachable.com/p/the-simple-algorithm
Learn how I draw my figures and diagrams in Inkscape (for everyone):
https://dr-aidan-wimshurst-s-school.teachable.com/p/inkscape-for-scientists-and-engineers
Did you like the video?
Download the lecture slides from my website:
https://www.fluidmechanics101.com/pages/lectures.html
Buy me a coffee to say thanks:
https://www.buymeacoffee.com/NKEZrhvg0
Support the channel on Patreon (and get useful extras for your CFD studies):
https://www.patreon.com/fluidmechanics101
Donations:
1) PayPal
https://www.paypal.me/fluidmechanics101
Disclaimer
The methods, algorithms, equations, formulae, diagrams and explanations in this talk are for educational and demonstrative purposes only. They should never be used to analyse, design, accredit or validate real scientific / engineering / mathematical structures and flow systems. For such applications, appropriate trained, qualified and accredited (SQEP) engineers / scientists should be consulted along with the appropriate documentation, procedures and engineering standards. Furthermore, the information contained within this talk has not been verified, peer reviewed or checked in any way and is likely to contain several errors. It is therefore not appropriate to use this talk itself (or any of the algorithms, equations, formulae, diagrams and explanations contained within this talk) as an academic or technical reference. The reader should consult the original references and follow the verification and validation processes adopted by your company / institution when carrying out engineering calculations and analyses. Fluid Mechanics 101 and Dr. Aidan Wimshurst are not accountable or liable in any form for the use or misuse of the information contained in this talk beyond the specific educational and demonstrative purposes for which it was intended.")
