Modeling Unsteady Aerodynamic Response Due to Surface Deformation on a Mach 6 Fin Using a Parallel Shear Flow Approach*

Aerodynamic loads experienced by control fins on hypersonic vehicles can be modeled with varying levels of fidelity. Control fins that experience surface deformation may experience unsteady loads that are significantly impacted by complex local flow features. This work will study the aerodynamic response by approximating the known viscous base flow around a Mach 6 fin using a parallel shear flow. The Fourier-transformed linearized 2D Euler equations will be solved for a panel located on the fin undergoing a specified deformation in this parallel base flow. This approach will take into consideration the effect of the base flow itself on the governing equations and the flow solution. The results will be compared to piston theory variants that also incorporate viscous base flows, as well as to 2D Navier-Stokes unsteady CFD solutions. The comparison will be made over a range of parameters, including different Reynolds numbers, panel oscillation reduced frequencies, and panel mode shapes.