planes and missiles tested in air tunnels,but when the matter is supersonic speed behaviour, you have no chance to simulate it with air, so the option is going for more intense fluid, water (1000 times intense than air) . behaviour of objects in fluid compared with Reynold numbers, Speed x chracteristic length / kinematic viscosity is what means for Re, and For 40 F temperature air has K.viscosity of 1.46E-4, water has1.664E-5 ,this means you can conduct same test with 1/10 speed that needed in air tunner.
Here is referance for it , you might look that paper because its about one of the 1st Large cavitaiton tunnel in world established in David Taylor Model Basin
"Since the advent of practical high speed prime movers late in the
last century, the problems of the designer concerned with the motion of solid
bodies through water have been ever increasing whether they be with respect
to ship hulls, rotating blades, or the extreme speeds encountered with aircraftlaunched
or jet-driven ordnance bodies." Ripken J.F., Design Studies For a Closed-Jet Water Tunnel. 1951 ,University of Minnesota.
Ok it was my mistake to mention "supersonic" its just high speed ,for supersonic ones i will look some more sources.
