Dynamic Aeroelastic Analysis of Wing/Store Configurations
AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING AND MANAGEMENT
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Limit-cycle oscillation, or LCO, is an aeroelastic phenomenon characterized by limited amplitude, self-sustaining oscillations produced by fluid-structure interactions. In order to study this phenomenon, code was developed to interface a modal structural model with a commercial computational fluid dynamics program. LCO was simulated for a rectangular wing, referred to as the Goland wing. It was determined that the aerodynamic nonlinearity responsible for LCO in the Goland wing was the combination of strong trailing-edge and lambda shocks which periodically appear and disappear. This mechanism limited the flow of energy into the structure which quenched the growth of the flutter, resulting in a steady LCO. Under-wing and tip stores were added to the Goland wing to determine how stores affected limit-cycle oscillation. It was found that aerodynamic store shapes affect LCO in two off-setting ways under-wing stores interfere with the airflow on the lower surface of the wing which decreases LCO amplitudes, whereas, aerodynamic forces on both under-wing and tip stores directly increase LCO amplitudes.
- Fluid Mechanics