Delta Wing with Store Limit-Cycle-Oscillation Modeling Using a High-Fidelity Structural Model

Abstract

The flutter and limit-cycle oscillation behavior of a 45-deg delta-wing-store model with various store spanwise locations is studied using an aeroelastic model that includes a high-fidelity nonlinear finite element structural solver and a vortex-lattice aerodynamic model. The store aerodynamics are modeled using slender-body theory. The computed results are compared with a previous computational model and with the experiment. The zero-angle-of-attack flutter behavior of the wing-store configuration is shown to be sensitive to the spanwise store location. This is predicted accurately using the current methodology. Limit-cycle oscillation results for zero angle of attack are computed for two store spanwise locations and compare favorably with the experiment. For a clean-wing configuration and a configuration that had the store located at y/c = 0.291, the flutter results show very little sensitivity to the model angle of attack. This too was predicted accurately using the current model. However, when the store is placed at y/c = 0.545, the experimental flutter data show a large sensitivity to angle of attack, with the flutter velocity decreasing by almost 20% when the model is placed at an angle of attack of 2 deg. This is not predicted in the current work and it is possible that unmodeled flow physics such as leading-edge vortices are the cause of this difference.