Method for detecting sound field parameter in fluid medium by using laser vibrometer

Abstract

The invention discloses a method for detecting a sound field parameter in a fluid medium by using a laser vibrometer. A transmitting transducer is arranged in a measured water pool through a mounting and positioning mechanism, a laser vibrometer probe is mounted on the surface of the water pool through a three-dimensional positioning device, laser is vertically projected onto an interface of water in the water pool and air, and the sound axes of the laser beam and the transmitting transducer coincide; and the interface between the liquid medium and the air is used as a reflection face of a laser beam, and the sound field parameter is detected by an optical method to obtain a sound pressure. The method has the advantages that: the need of arranging reflecting and sound transmitting membrane in a sound field is obviated, and the measurement steps are simplified. As it is unnecessary for a measuring light beam to pass through the inside of fluid, the value of real vibrating velocity of amass point can be obtained without taking the influences of an acoustooptic effect on the light beam into consideration nor correcting the test result; the value of the sound pressure can be obtaineddirectly according to the relationship between the sound pressure and the mass point; and the efficiency of the measurement is improved.

Description

technical field [0001] The invention relates to the field of sound field parameter measurement and calibration, and mainly relates to a method for detecting sound field parameters in a liquid medium by using a laser vibrometer. Background technique [0002] In underwater acoustic scientific research and production activities, underwater acoustic sound pressure is a basic physical parameter. The measurement and value transmission of underwater acoustic sound pressure have always been carried out through hydrophones, which is a method of directly measuring sound pressure. In order to ensure the accuracy of the underwater sound pressure value, the sensitivity of the transfer hydrophone and the standard hydrophone must be calibrated and measured. Commonly used calibration methods are the reciprocity method and the comparison method. The reciprocity method has always been the preferred method for hydrophone calibration, but the reciprocity method requires three sets of installat...

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Problems solved by technology

[0008] It can be seen that the equivalent refractive index depends on many factors such as the form of the sound wave (plane wave, spherical wave, etc.), frequency, and the location of the diaphragm in the sound field, so it will have a greater impact on the correction of the measurement results

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