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Reduced-Order Modeling of a Heaving AirfoilA reduced-order model of a flapping airfoil is developed using Proper Orthogonal Decomposition (POD). The proper basis functions, developed from snapshots of full Navier-Stokes simulations, are used for a Galerkin projection of the governing equations. The resulting coupled, nonlinear ordinary di.erential equations have a low dimension because the first few basis members capture most of the energy of the flow. The reduced-order model is used to simulate heaving motions that are both similar to and different from the motion(s) used to generate the basis functions, and the errors in the model are quantified. Several methods are used to generate mode sets that can be used over a range of heaving parameters, including snapshots from one, two, and multiple Navier-Stokes simulations. As snapshots from additional simulations are added to the decomposition, the mode sets become richer and can simulate a wider range of parameter space, at some computational cost. Whereas the POD method is fully applicable in three dimensions, the simulation technique based on a body-fixed and body-fitted grid suffers large overhead when extended to three dimensions. To reduce the overhead, an embedding technique is discussed which embeds the solid wing into a fixed Cartesian grid. The wing, which can now have multiple pieces and also be flexible, is represented by a distribution of body forces. This distribution is determined to give exactly the flow around a flapping wing.
Document ID
20050232860
Acquisition Source
Langley Research Center
Document Type
Conference Paper
Authors
Haj-Hariri, H.
(Virginia Univ. Charlottesville, VA, United States)
Murphy, P. C.
(NASA Langley Research Center Hampton, VA, United States)
Lewin, G. C.
(Avir, LLC Charlottesville, VA, United States)
Date Acquired
August 23, 2013
Publication Date
January 1, 2005
Subject Category
Aircraft Design, Testing And Performance
Report/Patent Number
AIAA Paper 2005-6168
Meeting Information
Meeting: AIAA Guidance, Navigation, and Control Conference and Exhibit
Location: San Francisco, CA
Country: United States
Start Date: August 15, 2005
End Date: August 18, 2005
Sponsors: American Inst. of Aeronautics and Astronautics
Funding Number(s)
CONTRACT_GRANT: NAG1-01120
OTHER: 23-762-65-AG
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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