The fluid-structure interaction phenomenon is the main cause of flow-induced vibrations at the blade passing frequency in large and high pressure centrifugal pumps. One way to reduce the effects of this interaction and pump vibration is to increase the effective gap by cutting the blade exit of the impeller. However, this cut of the impeller blade will affect the pump head and the flow pattern inside the pump volute. A single stage of a double volute centrifugal pump is used to investigate the

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... ffect of increasing the effective gap, by cutting the impeller blade exit with different shapes, on pump performance and vibration. Different cut shapes are tested, namely V-shaped cut, C-shaped cut, and straight cut. Results showed the minimum pressure fluctuations inside the pump agree with the minimum pump vibration at the best efficiency point of the pump. Operating at off-design conditions increases the pump vibration. The cut at the blade exit increases the effective gap between the impeller and volute tongues and allows the dissipation of pressure pulse energy and pump vibration. The shape of the cut shows noticeable effect on the pump vibration and performance. Index Terms-Flow induced vibration, double volute pump, different cut-shapes at blade exit, pump performance and vibration.