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Simulation of Non-Linear Transonic Aeroelastic Behavior on the B-2At high subsonic flight speeds, large flexible aircraft begin to encounter unsteady airloads which are not predicted by most currently available aerodynamic analysis and design methods. With increasing speed and the development of transonic flow and shocks, viscous effects quickly become very important, and flow separation can occur. The Northrop Grumman USAF B-2 Bomber encountered a nonlinear aeroelastic Residual Pitch Oscillation (RPO) under these conditions. Simulation studies were performed with the Computational Aeroelasticity Program-Transonic Small Disturbance, Viscous (CAPTSDv) computer program to evaluate its ability to predict these nonlinear aeroelastic responses. Open and closed loop simulations were performed to assess the participation of the flight control system. Control, system actuator hysteresis characteristics were modeled and found to be a significant participant in the RPO phenomenon. Simulations were also performed for varying Mach numbers and altitudes to establish the stability boundaries and compare with flight test data. These CAPTSDv simulations compared well with flight data and revealed many potential further modeling enhancements.
Document ID
19990052682
Acquisition Source
Langley Research Center
Document Type
Conference Paper
Authors
D. R. Dreim
(Northrop Grumman (United States) Falls Church, United States)
S. B. Jacobson
(Northrop Grumman (United States) Falls Church, United States)
R. T Britt
(Northrop Grumman (United States) Falls Church, United States)
Date Acquired
August 19, 2013
Publication Date
June 1, 1999
Publication Information
Publication: CEAS/AIAA/ICASE/NASA Langley International Forum on Aeroelasticity and Structural Dynamics 1999
Issue: Pt. 2
Subject Category
Aircraft Design, Testing And Performance
Meeting Information
Meeting: CEAS/AIAA/ICASE/NASA Langley International Forum on Aeroelasticity and Structural Dynamics 1999
Location: Williamsburg, VA
Country: US
Start Date: June 22, 1999
End Date: June 25, 1999
Sponsors: American Institute of Aeronautics and Astronautics, National Aeronautics and Space Administration, Confederation of European Aerospace Societies, Institute for Computer Applications in Science and Engineering
Funding Number(s)
CONTRACT_GRANT: NAS1-19347
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
Keywords
Residual pitch oscillation
Limit cycle oscillation
Shock induced oscillation
Transonic aerodynamics
Body freedom flutter
Hump mode
Computational fluid dynamics
Computational aeroelasticity
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