Wing Rock Prediction in Free-to-Roll Motion Using CFD Simulations

The free-to-roll wing rock CFD simulation of a slender 80-degree delta wing is performed using the Dynamic Fluid-Body Interaction (DFBI) framework and the overlap/chimera mesh method. The purpose of the simulations carried out was to test the capabilities of the current CFD methods for predicting wing rock motion over a wide range of angles of attack, including strong conical vortex interactions and vortex breakdown phenomenon. The predictions of steady aerodynamic dependencies and the aerodynamic stability derivatives based on forced oscillation tests along with the time histories of the wing rock motion of an 80-degree delta wing are in good qualitative and quantitative agreement with the available wind tunnel experimental data demonstrating onset of the wing rock motion. At higher angles of attack with vortex breakdown CFD simulations demonstrated an excitation of the large amplitude regular oscillations or the low amplitude chaotic oscillations depending on the applied initial conditions.