ANALYSIS OF VIBRATIONS OF THE NATIONAL TRANSONIC FACILITY MODEL SUPPORT SYSTEM USING A 3-D AEROELASTIC CODE

© American Institute of Aeronautics and Astronautics, Inc., 1989. All rights reserved. Vibrations of the National Transonic Facility model support system wn analyzed using CAP-TSD (Computational Aeroelasticity Program-Transonic Smell Disturbance), a three* dimensional transonic small disturbance coda designed for aeroelastic analysis of complete aircraft. The model support system was represented as a tunnel-spanning flexible wing whose structural properties were obtained from measured responses. Aeroelastic transients were calculated and analyzed to obtain modal stability characteristics. The analyses were performed assuming no structural damping. The results show that there is tendency to exhibit a hump mode instability in one of the modes and that there are other weakly damped or unstable modes. Most of the motion is in the aft section of the model support system. The close proximity of the solid wind-tunnel diffuser side walls to the model support system is shown to have adverse effects on its aeroelastic stability characteristics. When the effects of the wind-tunnel walls are modeled, the analyses indicate the presence of wind-tunnel resonance modes which are not present when free-air boundary conditions are used.

ANALYSIS OF VIBRATIONS OF THE NATIONAL TRANSONIC FACILITY MODEL SUPPORT SYSTEM USING A 3-D AEROELASTIC CODE Conference Paper