Aeroelastic analysis of supersonic intake under downstream perturbation

Smart flexible structure is used to reduce moving equipments of modern supersonic intake with variable geometry design. As a result, aero-elasticity of flexible intake need to be considered in aircraft design. A fully coupled fluid structure interaction (FSI) computation framework was developed in present work to simulate aero-elasticity of a two-dimensional supersonic intake model with flexible cowl wall under downstream back pressure perturbation. Transonic viscous flow in the intake was solved using finite volume method. Finite element method was used to model dynamic response of flexible wall through, consideration of geometric non-linearity. Unsteady flow in the intake with rigid wall under back pressure perturbation shows a large amplitude oscillation of shock train, which includes a period of shock train appearing and disappearing. It is found in FSI results that flexible cowl wall vibrates with downstream perturbation frequency, although multiple frequency components excitation loads are found in spectrogram. Wall flexibility plays the role of 'buffer zone', which limits the formation of large amplitude shock train oscillation during FSI process. Structural damping could be used to enlarge 'buffer zone' effect.