Abstract

SKEWS, B.W.; BREDIN, M.S.  and  EFUNE, M.. Drag Measurement in Unsteady Compressible Flow Part 2: Shock Wave Loading of Spheres and Cones. R&D j. (Matieland, Online) [online]. 2007, vol.23, pp.13-19. ISSN 2309-8988.

The measurement of aerodynamic drag encountered by spheres and cones exposed to strongly transient flows such as those due to shock wave impact is undertaken. A specially designed stress wave drag balance is used to record the forces during the transit of the wave over the body and for a short time thereafter. Post-shock Reynolds numbers were varied over the range from 2 x 10^s to 6 x 10^s. Numerical simulations were run in order to help interpret the drag variations. For the sphere the maximum drag occurs just before the shock wave reaches the equator whereas for the cones it occurs when the shock reaches the cone base. The post-shock drag variations are shown to be largely due to wave reflections within the shock tube. Good agreement is obtained between the measured and numerically predicted peak drag values. Comparisons are also made with published steady state drag values, predominantly obtained from incompressible data, as well as steady state compressible values from numerical simulations at the test post-shock Mach numbers.