[my_cfd]

Hello all,

I am newbie to fluid dynamics. How does one vary Mach number and dynamic pressure independently in a wind tunnel. i want to repeat the same in CFD.

Thanks,
Jane

[Amiga500]

Originally Posted by my_cfd

Hello all,

I am newbie to fluid dynamics. How does one vary Mach number and dynamic pressure independently in a wind tunnel. i want to repeat the same in CFD.

Thanks,
Jane

Pt/P = {1+ [((gamma-1)/2)*Mach^2]} ^(gamma/[gammma-1])

Pt = Total pressure
P = Static pressure
gamma = ratio of specific heats (1.4 for air)
Mach = Mach number


Change your static pressure, and you can adjust your total pressure & mach number semi-independantly of each other.


If your doing this in a wind-tunnel, you obviously need a pressurised tunnel.


Beware of Reynolds effects while doing this however. Matching compressibility effects with Reynolds effects on a scaled tunnel model is not possible*.

*at least, not that I'm aware.