Suppression of shock wave oscillations on a blunt cone-cylinder13; AIAA Paper 97-0299

The paper presents the experimental investigations on a blunt cone-cylinder made in the DLR 1- x 1-m Transonic Wind Tunnel to suppress shock wave oscillations and control flow unsteadiness using a passive control technique. Porous surfaces of 10- and 15-percent porosity and of normal holes and cavities of two different depths were introduced in the cylindrical portion immediately behind the blunt cone-cylinder junction, and their effectiveness was studied at Mach numbers ranging from 0.75 to 0.93 and angles of incidences of -4, 0, 2, 4, and 8 deg. The steady and unsteady surface pressures and cavity pressure measurements show that passive control of shock wave/boundary layer interactions reduces the amplitude of the pressure fluctuation and the pressure gradient. Schlieren pictures show, as expected, that the strong shock wave is split into weaker shock waves and compression waves on the porous surface