The effect of streamwise pressure distribution on the aeroelastic deformation of hypersonic trailing-edge flaps

This research studies the effects of surface pressure distribution and pressure gradient, introduced by the convex surface curvature, on the aeroelastic characteristics of hypersonic aerodynamic surfaces. An inclined trailing-edge flap model cantilevered at the back of a rigid plate is used to form a compression corner configuration. The aeroelastically-deformed convex shape of a planar flap model is taken as a baseline profile and the inclination is changed to obtain different net pressure distributions over the flap compression surface. The higher initial incidence angle of a convex surface leads to a higher pressure gradient near the flap leading-edge and a forward shift in the center of pressure. This study investigates the effects of this surface pressure distribution on the steady-state aeroelastic characteristics of the trailing-edge flap model. The numerical study was performed using the US3D code to generate laminar and turbulent solutions. The computed surface pressure distributions were used to calculate the static deformed shape of the flap. The laminar flow cases showed little difference in deformation of the flap due to a large separated region at the compression corner that resulted in identical pressure distribution regardless of the surface curvature. For the turbulent flow cases, the large pressure gradients near the compression corner changed the aeroelastic deformation of the flap with the introduction of surface curvature. For the same amount of loading, the tip deflection of a convex flap was reduced by approximately 11% in comparison to a planar flap.