Near-field acoustical holography measurement method in limited space based on equivalent source method

Abstract

The invention discloses a near-field acoustical holography measurement method in a limited space based on an equivalent source method, and the method comprises the steps: 1, building a near-field acoustical holography measurement model in the limited space, and obtaining the sound pressure and vibration velocity of a sound source in a measurement surface in the limited space: 2, configuring the number of virtual sources and the positions of the virtual sources; 3, establishing a near-field acoustical holography measurement model of the monopole point sources in the limited space, and obtaining the sound pressure vibration velocity of each monopole point source in a measurement surface in the limited space; 4; solving a Green function in the limited space; 5, solving sound pressure and vibration velocity information on a sound source measurement surface of the known structure through the transfer relation solved in the previous step to obtain the source intensity of the equivalent source in the structure; 6, calculating information such as sound pressure of the structure in the free field through the solved source intensity of the equivalent source. According to the method, a limited space test environment is considered, a traditional equivalent source method is improved, and the influence of an interface in a limited space on sound pressure and a vibration velocity field of a source surface is considered, so that the reconstruction precision is improved.

Description

technical field [0001] The invention relates to a transformation method for improving the reconstruction accuracy of sound pressure on a structure source surface in the field of acoustic holography, in particular to a near-field acoustic holographic measurement method in a limited space based on an equivalent source method. Background technique [0002] Near-field acoustic holography technology reconstructs the near-field acoustic signal close to the sound source surface through the sensor to obtain acoustic quantities such as sound source surface sound pressure and surface particle vibration velocity, and obtain various acoustic information of the three-dimensional space field. Compared with traditional acoustic holography or other noise measurement methods, the acoustic signal collected by near-field measurement has a higher signal-to-noise ratio, and the reconstructed image is clear and resolvable. Therefore, NAH technology is a very effective sound field visualization te...

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Problems solved by technology

The above literature does not consider the influence of multiple reflections of sound waves on the limited space interface on the sound field. Therefore, there must be large errors in the reconstruction results using the above methods

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