Effects of the geometry of impinging surface on the pressure oscillations of self-resonating pulsed waterjet

A preliminary experimental investigation was performed with a focus on the axial pressure oscillations of self-resonating pulsed waterjet under different impinging surfaces. Five target plates of different impinging surfaces were impinged by self-resonating pulsed waterjets at various standoff distances and under four inlet pressures. It was found that the geometry of impinging surface significantly affects the pressure oscillation peak and amplitude of self-resonating pulsed waterjet, and the influences largely depend on the inlet pressure. Both the pressure oscillation peak and the amplitude increase to their maximum and then drop with increasing standoff distance, which is regardless of the geometry of impinging surface. But the geometry influences the values of the optimum standoff distance and the oscillation peak and amplitude. Compared with the trend of pressure oscillation peak against standoff distance, the oscillation amplitude can be more obviously changed by the impinging surface. Moreover, an assumption that the geometry affects the pressure oscillation peak by the rebound waterjets and hydroacoustic waves has been proposed based on related literature. Further study should be conducted to clarify the relations between the axial pressure oscillation and the geometry of impinging surface.