Comparison of different approaches for gust modeling in the CFD Code TAU

Kurzfassung

Two different methods for modeling of gusts have been implemented into the CFD-code TAU. The first one is the so called disturbance velocity approach, a simplified method which allows predicting the influence of a gust on the aircraft, but not the influence of the aircraft aerodynamics on the shape of the gust. Alternatively, an unsteady boundary condition has been implemented to feed in the gust into the flow field. Thereby the mutual interaction of gust and aircraft is captured. Both methods are compared in order to access the validity range of the simplified approach. A result is that for gust wavelength larger than two reference chords the agreement of the highly accurate method and simplified approach is good. For such cases the simplified approach has been used to simulate the gust interaction of a generic fighter aircraft and an A340 configuration, taking into account the reaction of the aircraft due to the additional loads.