Abstract
To make progress the technique of forecasting a serious plant trouble caused by acoustic resonance and sympathetic vibration, vibration experiments were performed using an actual mock-up piping by sweep test and steady operations of pump, and numerical simulations for the experiments were performed. When experimental condition of the valve opening ratio were changed from 5% to 30% or when experimental condition of the pipe diameter were changed from 3/ 4B to 1B, the simulation results were agreement with the experiment ones on the whole.