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The Origin of Inlet Buzz in a Mach 1.7 Low Boom Inlet DesignSupersonic inlets with external compression, having a good level performance at the critical operating point, exhibit a marked instability of the flow in some subcritical operation below a critical value of the capture mass flow ratio. This takes the form of severe oscillations of the shock system, commonly known as "buzz". The underlying purpose of this study is to indicate how Detached Eddy Simulation (DES) analysis of supersonic inlets will alter how we envision unsteady inlet aerodynamics, particularly inlet buzz. Presented in this paper is a discussion regarding the physical explanation underlying inlet buzz as indicated by DES analysis. It is the normal shock wave boundary layer separation along the spike surface which reduces the capture mass flow that is the controlling mechanism which determines the onset of inlet buzz, and it is the aerodynamic characteristics of a choked nozzle that provide the feedback mechanism that sustains the buzz cycle by imposing a fixed mean corrected inlet weight flow. Comparisons between the DES analysis of the Lockheed Martin Corporation (LMCO) N+2 inlet and schlieren photographs taken during the test of the Gulfstream Large Scale Low Boom (LSLB) inlet in the NASA 8x6 ft. Supersonic Wind Tunnel (SWT) show a strong similarity both in turbulent flow field structure and shock wave formation during the buzz cycle. This demonstrates the value of DES analysis for the design and understanding of supersonic inlets.
Document ID
20140016538
Document Type
Conference Paper
Authors
Anderson, Bernhard H.
(NASA Glenn Research Center Cleveland, OH United States)
Weir, Lois
(TechLand Research, Inc. North Olmstead, OH, United States)
Date Acquired
November 21, 2014
Publication Date
July 28, 2014
Subject Category
Aerodynamics
Report/Patent Number
GRC-E-DAA-TN15470
Meeting Information
Meeting: Joint Propulsion Conference
Location: Cleveland, OH
Country: United States
Start Date: July 28, 2014
End Date: July 30, 2014
Sponsors: American Inst. of Aeronautics and Astronautics, American Society for Engineering Education, Society of Automotive Engineers, Inc.
Funding Number(s)
WBS: WBS 475122.02.03.03.01
Distribution Limits
Public
Copyright
Public Use Permitted.
Keywords
Mach 1.7
Low Boom
Inlet Buzz
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