Control of Acoustics and Store Separation in a Cavity in Supersonic Flow
Abstract
The supersonic flight community is currently faced with two cavity-under-cross-flow related problems, one being the high noise levels inside the cavity and the other being the return of a store into the cavity after being released from inside. This thesis provides a systematic framework to understand the dominant physics in both problems and to provide solutions for ameliorating the problems. For the first problem, an innovative cavity acoustics model is developed that rigorously explains the role of leading edge microjets in cavity noise suppression and predicts the magnitude of noise reduction for a given control input (that is the steady pressure at which the microjets are fired). The model is validated through comparison of its noise reduction predictions with experiments done using the Florida State University cavity and wind tunnel for different microjet pressures and under Mach 2.0 and Reynolds number 3 million flow, with the microjets being of diameter 400 microns. The second problem that the thesis is concerned with, is that of unsuccessful store drops from an external bay of an aircraft in flight. A group of researchers under the DARPA-funded HIFEX Program is currently developing an effective control mechanism to ensure safe release of a slender axi-symmetric store from a rectangular cavity under supersonic external cross-flow. In this thesis, a suitable low-order model is developed with separate components to predict the pitch and plunge motion of the store when it is inside the cavity, when it is passing through the shear layer at the mouth of the cavity and when it is completely outside the cavity. The model is based on slender axi-symmetric body aerodynamics, thin shear layer at the cavity mouth, high Reynolds number external cross-flow, plane shock waves associated with the microjet actuators, no-flow condition inside the cavity and inconsideration of the cavity acoustic field.
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 01, 2005
- Accession Number
- ADA453973
Entities
People
- Debashis Sahoo
Organizations
- Massachusetts Institute of Technology