基于流固耦合作用的分布反馈式光纤激光水听器

DFB Fiber Laser Hydrophone Based on Fluid-structure Interaction

为了解决流固耦合模态使水听器工作频带变窄的问题,理论分析了流体对双膜片结构的分布反馈式光纤激光水听器固有频率的影响,基于有限元软件对水听器加固封装前后在空气中和流体中的模态和频响性能进行仿真分析,加工制作了水听器原型样品并开展了水声实验研究.实验结果表明,在2 500~8 000Hz的频率范围内,未经加固封装的水听器由于在该频段内存在多个流固耦合固有频率造成响应曲线起伏较大,而采取了加固措施封装后的水听器获得了-142.77±0.8dB的平均声压灵敏度,验证了流体对水听器频响性能的影响以及改善措施的有效性,实验结果与理论及仿真结果吻合较好.

To solve the problem that fluid-structure coupling mode makes the frequency band of hydrophone narrowed, the influence of fluid on the natural frequency of the distributed feedback fiber laser hydrophone with two diaphragms was theoretically analyzed. Based on the finite element software, the mode and frequency response performance of the hydrophone in the air and fluid before and after the reinforcement were simulated. Prototypes of the hydrophone were fabricated and tested. The results show that response curve of the hydrophone before reinforcement fluctuates greatly due to the existence of several natural frequencies in a frequency range of 2 500-8 000 Hz. The average acoustic pressure sensitivity of the hydrophone reaches 142.77±0.8 dB after reinforcement, which verifies the influence of fluid on the frequency response performance of the hydrophone and the effectiveness of the measures. It agrees well with both the theoretical analysis and simulation results.