Transonic buffet alleviation via virtual control surfaces

Abstract

In this work, computational fluid dynamics simulations are carried out to assess the ability of control surfaces to alleviate or suppress transonic buffet. Among the available control surfaces, upper trailing edge flaps were considered since they modify the aerofoil pressure distribution and fix the shock at an upstream position. Spoilers were also studied as they produce a similar effect by interfering with the pressure disturbance propagation in the boundary layer and prevent buffet. For both devices, the sensitivities to geometric parameters are studied. The effectiveness of these buffet control methods is first assessed for 2D computations around different wing sections. As spoilers were considered more effective, results on a 3D configuration are provided to discuss the influence of finite-span devices on aerodynamic performance. In addition, a simple model accounting for changes in the flight Mach number together with the spoiler is presented to simulate a simple flight scenario and provide an effective strategy for buffet suppression. In the framework of numerical investigations, the adoption of virtual control surfaces allows for avoiding difficulties associated with the modelling of slotted and deployable devices.