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Transonic Shock Oscillations and Wing Flutter Calculated with an Interactive Boundary Layer Coupling MethodA viscous-inviscid interactive coupling method is used for the computation of unsteady transonic flows involving separation and reattachment. A lag-entrainment integral boundary layer method is used with the transonic small disturbance potential equation in the CAP-TSDV (Computational Aeroelasticity Program - Transonic Small Disturbance) code. Efficient and robust computations of steady and unsteady separated flows, including steady separation bubbles and self-excited shock-induced oscillations are presented. The buffet onset boundary for the NACA 0012 airfoil is accurately predicted and shown computationally to be a Hopf bifurcation. Shock-induced oscillations are also presented for the 18 percent circular arc airfoil. The oscillation onset boundaries and frequencies are accurately predicted, as is the experimentally observed hysteresis of the oscillations with Mach number. This latter stability boundary is identified as a jump phenomenon. Transonic wing flutter boundaries are also shown for a thin swept wing and for a typical business jet wing, illustrating viscous effects on flutter and the effect of separation onset on the wing response at flutter. Calculations for both wings show limit cycle oscillations at transonic speeds in the vicinity of minimum flutter speed indices.
Document ID
19960054470
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Edwards, John W. (NASA Hampton, VA United States)
Date Acquired
September 6, 2013
Publication Date
January 1, 1996
Subject Category
Aerodynamics
Report/Patent Number
NAS 1.15:110484
NASA-TM-110484
Report Number: NAS 1.15:110484
Report Number: NASA-TM-110484
Meeting Information
Meeting: EUROMECH-Colloquium: Simulation of Fluid-Structure Interaction in Aeronautics
Location: Gottingen
Country: Germany
Start Date: September 16, 1996
End Date: September 19, 1996
Accession Number
96N36616
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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