This work is an experimental and numerical investigation of the flow induced vibration problem at blade passing frequencies of a high-pressure double volute boiler feed pump. The effects of variable operating conditions and different design modifications were studied by model testing to minimize the vibration level. The amplitude and strength of the pressure fluctuation inside the pump depend on the measuring location with respect to the interaction zone at volute tongues. The unsteady pressure fluctuations are very sensitive to the flow rate. Pressure fluctuations are increased at high...