| Abstract: | Questions associated with the interaction between a gas stream and a body in a launching tube, especially the high-speed propulsion of a body by a gas stream 1], have become of great interest in recent years. Partial destruction of the body and the formation of a gap between the body and the launching tube, through which the working gas will flow, inevitably occurs at high velocities. In this case it is possible to consider the ejection of a free body which does not come into contact with the walls of the launching tube as it is accelerated. An analogous problem occurs in the transportation of containers in a tube under the effect of a compressed gas 2], as well as in a gas-dynamic analysis of piston apparatus with different kinds of gas flow through the orifice inmoving or fixed pistons. The interaction between the gas stream and the body or the obstacle in the launching tube must be known for a theoretical investigation of all these problems. The solution is obtained by numerical integration of the nonstationary gas-dynamic equations by means of a through-computation difference scheme 3]. Values of the blockage factors are found for different freestream Mach numbers, for which the reflected shock stands off at infinity upstream. A comparison is given with the one-dimensional approximation obtained under the assumption that the body being streamlined is replaced by two jumps of a strong discontinuity on which the mass, momentum, and energy conservation conditions are satisfied. The results obtained are used in the problem of ejection of a free body from a launching tube under the effect of an unsteady gas flow.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 4, pp. 81–86, July–August, 1978. |
