HYPERSONIC FLOWS PAST TRANSVERSE JETS.
GRUMMAN AIRCRAFT ENGINEERING CORP BETHPAGE N Y RESEARCH DEPT
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Reaction jets, when used within the atmosphere, can interact strongly with the local stream flow over a vehicle, and produce a resulting force that is much larger than the pure reaction force. Increased surface pressures, caused by the interaction of hypersonic streams with essentially two dimensional transverse jets, are found experimentally to depend strongly on jet and local stream flow conditions. Unlike interactions with supersonic stream flows, overpressures measured on the surface downstream of the jet orifice can contribute the major portion of the interaction force. Although weaker jets are generally more effective, giving greater amplification of the reaction force, the interaction force is greatly reduced when the jet flow is immersed in a thick boundary layer. Shock tunnel results obtained for local stream flow Mach numbers from 9 to 16 are presented and compared with analytical methods for predicting the interaction pressure distribution. Generally, the increased pressure levels can be estimated and used to obtain a first order correction to the interaction force. However, the extent of flow separation and details of the pressure distribution cannot be predicted adquately without additional information. Test results for transverse jet control forces compare favorably with those generated by a typical trailing edge flap. Author
- Fluid Mechanics