Control of acoustics and store separation in a cavity in supersonic flow

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. Based on the cavity acoustics model, optimization of the control input is performed for microjet-based noise suppression of a general cavity under external cross-flow. The resulting control strategy for the FSU cavity is that of an open loop steady microjet firing with the pressure being uniform along the leading edge. This corresponds to a noise reduction of 9 dB OASPL and 20 dB SPL at the dominant tone. The cavity also exhibits saturation in noise reduction for microjet pressures higher than 30 psig. 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

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Aeronautics and Astronautics.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2005

Author dc:creator

• Sahoo, Debashis, 1976-

Advisor dc:contributor.advisor

• Anuradha M. Annaswamy.

• Aeronautics and Astronautics.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/28915
• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Identifier URI

http://dspace.mit.edu/handle/1721.1/28915

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/28915