Uploaded December 2017 | Updated September 2026, 10 hours ago
Mechanical and Aerospace Engineers!
Typical commercial aircraft have an airfoil which is subsonic, i.e. the flow is streamlined in order to obtain a higher pressure at the bottom and a lower pressure at the top. This is the fundamental cause of lift.
However, for supersonic flight, the flow tends to 'compress' and 'expand' since the high Mach Number (airspeed relative to the speed of sound) tends to crush (or expand) the air flying in front of the aircraft. When a supersonic flow turns a concave corner, it creates an oblique shock. The airspeed is reduced, however there is an increase in pressure and temperature. When the flow turns a convex corner, the reverse occurs.
A supersonic airfoil is designed in order to achieve a higher pressure at the bottom and a lower pressure at the top, just like any other airfoil. This condition must be achieved regardless, to generate a positive upward force on the aircraft. However, supersonic airfoils take advantage of oblique shocks and expansion waves to achieve this effect. The bottom leading edge is designed to create an oblique shock which leads to an increase in pressure and a decrease in velocity.
I walk you through a full example of a CFD simulation supersonic airfoil. This may be helpful if you are a student in Aerospace or Mechanical Engineering. In order to follow along better, you will be better off going over 'Isentropic Flow Relation' formulas which can be available anywhere, as well as Part 1 of this video where I cover the theory. These are standard methods used for compressible flow calculations.
Link to Part 1 where I cover supersonic airfoil theory: youtube.com/watch?v=rOnHCK58u-Y&t=35s
Best Wishes,
My Instagram: instagram.com/vinayak_desh
My Website: vinayakd.com
Mechanical and Aerospace Engineers!
Typical commercial aircraft have an airfoil which is subsonic, i.e. the flow is streamlined in order to obtain a higher pressure at the bottom and a lower pressure at the top. This is the fundamental cause of lift.
However, for supersonic flight, the flow tends to 'compress' and 'expand' since the high Mach Number (airspeed relative to the speed of sound) tends to crush (or expand) the air flying in front of the aircraft. When a supersonic flow turns a concave corner, it creates an oblique shock. The airspeed is reduced, however there is an increase in pressure and temperature. When the flow turns a convex corner, the reverse occurs.
A supersonic airfoil is designed in order to achieve a higher pressure at the bottom and a lower pressure at the top, just like any other airfoil. This condition must be achieved regardless, to generate a positive upward force on the aircraft. However, supersonic airfoils take advantage of oblique shocks and expansion waves to achieve this effect. The bottom leading edge is designed to create an oblique shock which leads to an increase in pressure and a decrease in velocity.
I walk you through a full example of a CFD simulation supersonic airfoil. This may be helpful if you are a student in Aerospace or Mechanical Engineering. In order to follow along better, you will be better off going over 'Isentropic Flow Relation' formulas which can be available anywhere, as well as Part 1 of this video where I cover the theory. These are standard methods used for compressible flow calculations.
Link to Part 1 where I cover supersonic airfoil theory: youtube.com/watch?v=rOnHCK58u-Y&t=35s
Best Wishes,
My Instagram: instagram.com/vinayak_desh
My Website: vinayakd.com
