Spatial and Temporal High Resolution Measurement of Bubble Impacts

The present paper deals with a feasibility study of a new cavitation measurement method developed at the Chair of Fluid Systems Technologies (TU Darmstadt). The measurement principle is based on the piezoelectric attributes of a thin PVDF-membrane. The eigenfrequency of the membrane in the range of GHz in combination with a special sampling concept by means of an electrode matrix enable the measurement principle to measure pressures both temporally and spatially resolved. Pressure histories generated by cloud cavitation are investigated by means of the new measurement method and comparisons with high-speed photographs give very promising results concerning the qualitative statements delivered with the measurement signals of the sensor. Furthermore, statistical evaluations of the intensity of the measured pressure signals were carried out and are in good agreement with results from damage experiments.