RESEARCH ON SLOT INJECTION INTO A SUPERSONIC AIR STREAM
Final rept. 16 Jan 1967-16 Aug 1968
MARYLAND UNIV COLLEGE PARK DEPT OF AEROSPACE ENGINEERING
Pagination or Media Count:
The results of an experimental and analytical study of tangential slot injection into a supersonic stream are presented. The experiments were performed in an atmospheric intake wind tunnel with freestream Mach numbers of 2.85 and 4.19. Injection of air, helium and carbon dioxide at various subsonic Mach numbers and one supersonic condition was considered. Experiments for the flow over of wedges with turning angles between 5 and 25 deg. located on the wall downstream of the injection are also reported. The principal data are in the form of spark schlieren photographs, interferograms and wall static pressure distributions. Density profiles at several axial stations determined from interferograms are also presented. The transition to turbulence in the shear layer and the character of the turbulence were observed from the spark schlieren photographs. The presence of separation zones was detected by small tufts or threads on the surface. With subsonic injection, it is found that the initial slot exit conditions are not arbitrary for a given injectant mass flow but are determined by the downstream interaction between the two streams. The flow field has many of the features of the now well-known base-flow problem. A relatively simple analysis is developed which predicts the initial jet exit conditions. Very good agreement with the experimental observations is achieved.
- Fluid Mechanics