Characteristics of flow-induced oscillation in deep cavity and preliminary analysis of energy harvesting

The acoustic characteristics of flow induced oscillation in deep cavity and the utilization method of fluid kinetic energy are studied. Through the numerical simulation of the flow field and sound field characteristics inside the resonant cavity, the effects of cavity structure size and flow rate on the internal acoustic oscillation response characteristics are explored. The appropriate deep cavity structure is selected to realize energy harvesting through the piezoelectric transducer. The effectiveness of the numerical model and calculation method is verified by experiments. The results show that the high acoustic pressure output of the first acoustic mode and the first hydraulic mode can be obtained in the flow rate range of the high-pressure gas transmission pipeline, by using a resonator with an opening diameter of 30 mm and a length of 230 mm. At a mean flow rate of 32.26 m·s^-1, a maximum pressure amplitude reaches 4.62 kPa. Under this model, the piezoelectric patch with h_p=1.0 mm is selected for test experiments, and the maximum open-circuit voltage is 1.99 V. The experimental results are consistent with the predicted results of the model, which fully shows the potential of flow induced oscillation in energy supply. This method not only enriches the utilization of environmental fluid kinetic energy, but also is expected to realize passive power supply in micro wireless electronic equipment on special occasions such as low power consumption, long distance and low maintenance.