Fluid-structure vibration of a transonic diffuser with flexible wall

Flexible wall vibration is coupled with unsteady transonic flow in a ramjet engine intake with large local wall flexibility at its diffuser, and affects total engine performance. The aero-elastic problem between transonic flow and local wall vibration in a diffuser was studied based on a fluid structure interaction method. Impact of flexible wall damping on diffuser fluid-structure vibration was analyzed. It is shown that fluid-structure vibration of the diffuser induced by self-sustained normal shock oscillation can be limited or suppressed through modifying flexible wall damping. Nondimensional vibration amplitude is 0.37 at the center of the flexible wall without structural damping. It is reduced to 0.22 for model with a stiffness proportional damping coefficient of 1×10^-5. Flexible wall vibration vanishes with an increased damping coefficient of 4×10^-5, and the transonic diffuser stays at a static balance status.