Different flow scenario for thin body subsonic motion in compressible fluid under free surface

摘要

The problem of thin body high speed motion in compressible fluid near free surface is regarded. The problem is relevant to thin impactor high speed penetration into fluid filled containment. The resistance and lift forces strongly depend on the depth of body motion under free surface. Due to that reason the response of containment on high velocity perforation depends on the amount of fluid in it. To obtain analytical solution the fluid is assumed occupying infinite semi-space, gravity is neglected as compared with fluid inertia. The solution was obtained for a two-dimensional problem of thin body motion in compressible fluid at a definite depth, constant velocity and inclination angle. The solution allows determining drag and lift forces in the limiting cases. It was shown that on Mach number tending to unity both forces infinitely increase. For relatively thin fluid layer above the moving wing the resistance force depends on body thickness, inclination and Mach number, while for relatively thick fluid layer the force depends on wing length, inclination angle and Mach number as well.