Abstract: A porous Squeeze Film Damper (PSFD) had been developed by BUAA on the basis of the normal Squeeze Film Damper (SFD).The investigation on its application indicates that the nonlinear vibration characteristics of rotor system with SFD,such as bistable jump,nonsynchronous response and "lock up" at rotor pin-pin critical speeds under quite high unbalance level are greatly improved or avoided with the PSFD system.In conformity with the calculation and analysis of the dynamic characteristics of the rotor system in a core engine,a new flexible-porous squeeze film damped support has been designed and used in the rotor system of this core engine for adjusting its critical speeds and controlling its vibration.It is shown that the data of the engine cell tests have a good agreement with the calculation results.