| With the application of vector hydrophone in various fields of underwater acoustic engineering,the calibration of vector hydrophone becomes more and more important.At present,the calibration of vector hydrophones is mostly carried out in the free-field or equivalent free-field in the high frequency band,and the calibration of vector hydrophones in the low frequency band is completed by using standing-wave tube in the laboratory.Different from the rigid wall condition of traditional standing wave tube,this paper will use elastic materials to construct a set of experimental devices for the sensitivity and directivity of vector hydrophone In low frequency band.In this paper,the distribution of the sound field in the standing-wave field is analyzed by the normal-wave method,the expressions of the axial sound pressure and acceleration of the standing-wave tube are given under the excitation condition,and the expressions of the sound pressure sensitivity in the sound pressure channel and the vector channel are derived.By using COMSOL,the natural frequency of the calibration tube,radiation surface and sound field inside the tube were simulated,and the dimensions of the calibration tube and radiation surface capable of vector hydrophone calibration in the frequency range of 3-315 Hz were determined.Then,Solidworks was used to draw the standing-wave tube and the parts needed to install the standing-wave tube,and a manual measurement system suitable for vector hydrophone calibration was designed and delivered to the factory for production.After processing is completed,a complete set of devices is built to measure the sound field in the standing-wave tube,and it is known that the axial sound pressure and acceleration in the standing-wave tube are in accordance with the theoretical law,and the section sound pressure fluctuation within 20 cm of water entering is within 0.5d B,which confirms that the system can calibrate the vector hydrophone within a certain frequency band. |
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