I. Introduction

Physical chemical processes, taking place around a body moving in the Earth's atmosphere and those of other planets at hypersonic velocity, have a significant influence on a surface temperature, boundary-layer state, parameters of the plasma appearing near a flight vehicle, and radio wave propagation. Nonequilibrium of hypersonic flows at high altitudes ( H ? 60 80 km) might noticeably influence the flight vehicle's aerodynamic characteristics. Investigation of properties of hypersonic flows connected with the previously mentioned processes is an urgent scientific problem that cannot be solved without accurate experimental investigations.

In this respect, shock tubes are effective instruments for the examination of gas behavior at high temperatures. The size of the shock tube is of great importance because it defines the duration of the working regimes, which is usually very short ( t<1 ms). The short duration of the working regime impedes aerodynamic research, such as the measurement of forces acting on models. However large-scale tubes and multidiaphragm operation schemes may provide the long quasi-stationary flow with sufficient duration required for aerodynamic tests.

It is noted that shock tubes do not completely simulate real hypersonic flight. First of all, ablation is usually encountered in real flight. This significantly affects...