Increasing the force with which a shock wave discharged from the channel acts on an obstacle by way of converting a normal pressure shock to a system of oblique shocks

Abstract

The results are given of experimental and numerical investigations of the effect produced on an obstacle by shock waves discharged from channels of different cross-sectional shapes (circle, square, cross). The pressure distribution on an obstacle mounted normally to the flow axis is measured. The experimental results are compared to the data of numerical calculation for determining the optimal modes as regards the duration of calculation and the cell size that produce the least difference between the experimental and numerical data. Calculations are performed of the gas flow behind a shock wave discharged from a channel of X-shaped cross section, and the distribution of pressure and temperature over the obstacle surface is plotted. It is found that the force with which a flow acts on an obstacle when discharged from a channel of X-shaped cross section is much greater than in the case of being discharged from a channel of round or square cross section. Shadow photographs show that this is due to the reduction of the loss of total pressure in the flow because of the conversion of the normal pressure shock to a system of oblique shocks.