Investigation of relaxation processes in flow about models in hypersonic wind tunnels of different types

The theoretical and experimental results are presented which relate to flows over such simple bodies as a semisphere, a wedge, and a cone investigated in hypersonic wind tunnels of various classes at similar Mach and Reynolds numbers (M=7.0 to 8.0; Re_o≃135 to 210) and at different air flow velocities (790^m/_s , 2700^m/_s and 6000^m/_s). Hypersonic resistor-type and arc-heating wind tunnels and a hypervelocity MHD-air acceleration wind tunnel, as well as their test equipment are described. Experimental data on pressure distribution on model surfaces, shock wave position and shape were obtained. For visualization purposes, an electron beam was used in the first wind tunnel and filming of natural flow glow was made by using neutral and interference light filters in the second and third wind tunnels. Use was also made of a specially developed shadow device based on the application of an abnormal dispersion effect of resonant emission of Na atoms. The experimental body flow data are compared with respective calculated results obtained by using the VSL theory and the Navier-Stokes equations. The data are in good agreement for the case of a perfect gas and satisfactory for the case of a gas with chemical reactions