Unsteady Aerodynamics and Hinge Moment Calculations of Control Surfaces at Transonic Speeds

This paper presents a methodology for calculating the hinge moment and its derivatives through computational tools applied to compressible transonic unsteady flows for control surfaces. The hinge moment is expressed as a function of both the angle of attack and the deflection angle of the control surface. The open-source multiphysics software SU2 is used to impose movement in both space and time through grid movement algorithms. Several two- and three-dimensional simulations are performed under various operating conditions. For most of the cases presented, the computational results exhibited good behavior, with the hinge moment demonstrating a periodic sinusoidal wave pattern. Furthermore, the mean of these unsteady computational results showed strong agreement with available experimental data, particularly in terms of the predicted hinge moment behavior and its sensitivity to flow conditions. However, in certain cases, primarily at high angles of attack, where the presence of multiple dominant frequencies in the unsteady flow significantly affects the results and can lead to boundary-layer separation, the flow exhibited complex, nonlinear behavior. These results demonstrate the ability of the methodology to effectively model unsteady transonic flows and predict hinge moments for realistic aerodynamic configurations.