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Numerical Generation of Asymmetric Flows about Slender Bodies of Revolution at Extreme IncidenceIt is well known that slender bodies of revolution will develop an asymmetric, unsteady flow pattern in experimental tests, if the angle of incidence to the oncoming stream is above a critical value. It has been suggested that the origin of these asymmetric flows may stem from geometric imperfections of the model being tested, or from disturbances in the oncoming stream. In numerical simulations, it is possible to generate bodies of revolution which are perfectly symmetric about their longitudinal axis, and to impose uniform flow conditions which are free from disturbances. The current work presents numerical simulations of the flow about an ogive-cylinder configuration at 40 and 60 degree angle of incidence. These simulations. were performed using numerical algorithms which are also symmetric about the lateral plane of the cylinder body. The flowfields at 40 degree angle of attack were seen to remain symmetric to the round-off accuracy of the computer. At 60 degree angle of attack, a lateral force coefficient developed of O(1) which progressed to an alternate vortex shedding in time. The nature of this lateral force generation and vortex shedding was dependent on the choice of numerical algorithm. The origin of the asymmetries observed in the 60 degree angle of attack computations were traced to round-off errors in the implicit block-matrix inverter. A means of inverting the implicit operator matrices, which maintains the symmetry of the overall numerical algorithm was implemented.
Document ID
20010121541
Acquisition Source
Ames Research Center
Document Type
Conference Paper
Authors
Murman, Scott M.
(MCAT Inst. Moffett Field, CA United States)
Schiff, Lewis B.
(NASA Ames Research Center Moffett Field, CA United States)
Kutler, Paul
Date Acquired
August 20, 2013
Publication Date
January 1, 1994
Subject Category
Fluid Mechanics And Thermodynamics
Meeting Information
Meeting: AIAA 33rd Aerospace Sciences Meeting and Exhibit
Location: Reno, NV
Country: United States
Start Date: January 9, 1995
End Date: January 12, 1995
Sponsors: American Inst. of Aeronautics and Astronautics
Funding Number(s)
PROJECT: RTOP 505-68-00
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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