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New Flutter Analysis Technique for CFD-based Unsteady AeroelasticityThis paper presents a flutter analysis technique for the transonic flight regime. The technique uses an iterative approach to determine the critical dynamic pressure for a given mach number. Unlike other CFD-based flutter analysis methods, each iteration solves for the critical dynamic pressure and uses this value in subsequent iterations until the value converges. This process reduces the iterations required to determine the critical dynamic pressure. To improve the accuracy of the analysis, the technique employs a known structural model, leaving only the aerodynamic model as the unknown. The aerodynamic model is estimated using unsteady aeroelastic CFD analysis combined with a parameter estimation routine. The technique executes as follows. The known structural model is represented as a finite element model. Modal analysis determines the frequencies and mode shapes for the structural model. At a given mach number and dynamic pressure, the unsteady CFD analysis is performed. The output time history of the surface pressure is converted to a nodal aerodynamic force vector. The forces are then normalized by the given dynamic pressure. A multi-input multi-output parameter estimation software, ERA, estimates the aerodynamic model through the use of time histories of nodal aerodynamic forces and structural deformations. The critical dynamic pressure is then calculated using the known structural model and the estimated aerodynamic model. This output is used as the dynamic pressure in subsequent iterations until the critical dynamic pressure is determined. This technique is demonstrated on the Aerostructures Test Wing-2 model at NASA's Dryden Flight Research Center.
Document ID
20090025456
Acquisition Source
Armstrong Flight Research Center
Document Type
Conference Paper
Authors
Pak, Chan-gi
(NASA Dryden Flight Research Center Edwards, CA, United States)
Jutte, Christine V.
(NASA Dryden Flight Research Center Edwards, CA, United States)
Date Acquired
August 24, 2013
Publication Date
June 21, 2009
Subject Category
Fluid Mechanics And Thermodynamics
Report/Patent Number
DFRC-934
Meeting Information
Meeting: International Forum on Aeroelasticity and Structural Dynamics (IFASD) 2009
Location: Seattle, WA
Country: United States
Start Date: June 21, 2009
End Date: June 25, 2009
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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