Modeling of Buffeting Fluctuating Loading and Computing the Resulting Force and Bending Moment of the Aircraft

Buffeting is a high frequency aeroelastic instability that occurs in transonic speeds. The main objective of this paper is to present a method for determining the loading caused by this phenomenon on the body of the vehicle. For this، vibration equations are transformed into frequency domain. Then، the vehicle’s geometry and the kind of flow around the vehicle have been identified and for each of these flows، formulations are presented to predict the power spectral density of the external loading due to the buffeting phenomena، using experimental and statistics methods. The applied aeroelastic moment on the vehicle was calculated by determining the buffeting loads around the vehicle in frequency domain. Aerodynamic damping، which is calculated using experimental relations and quasi-steady flow presumption، was used for this aim. The results show that shock wave can apply a huge torque on the body، which is more than that obtained by static calculations. Thus، investigation of buffeting phenomena is necessary to have a successful launch. The presented method could be used in a wide range of space vehicles without expensive experimental analysis. The results were verified by experimental data from other reliable resources.