Question

Which one do you think is not possible with wind tunnels for testing trans-atmospheric vehicles?

(a) Continuously changing Mach number

(b) Transonic flows

(c) Simultaneously modelling high Mach numbers and high temperatures

(d) Hypersonic flows

The question was posed to me in an international level competition.

Question is taken from Philosophy topic in section Philosophy of Computational Fluid Dynamics of Computational Fluid Dynamics

Answer 1

Correct choice is (c) Simultaneously modelling high Mach numbers and high temperatures

To explain: Continuous change in Mach numbers can be done in wind tunnels. Transonic and hypersonic wind tunnels also exist. If we try to model high speeds at high temperatures, the wind tends to reduce the temperature as we have wind flowing over the stationary model in a wind tunnel.