Parameter modulation method of sub-wavelength structure for eliminating broadband reflection sound waves in curved path

Abstract

The invention relates to a parameter modulation method of a sub-wavelength sound transparent structure for eliminating broadband reflection sound waves in a curved path. Specifically, a sub-wavelength sound transparent structure unit is formed by inserting a sub-wavelength scale rigid thin plate into an acoustic unit, and background fluid is air. Sub-wavelength structure target parameter distribution is deduced according to known straight waveguide physical parameters, and geometric parameters and temperature distribution corresponding to the structure are obtained according to the sub-wavelength acoustic transparent structure target parameters. The sizes of the water storage container and the water inlet opening surrounding the waveguide are controlled, and target temperature distribution is generated on the waveguide through hot water with the fixed temperature. The bent part of the waveguide is filled with a corresponding sub-wavelength sound transparent structure, so that broadband sound waves can be guided along a bent path without any reflection or scattering. The sub-wavelength acoustic transparent structure has good scattering elimination performance, can be perfectly matched with background fluid by designing structural impedance, and has the effect of controlling and keeping a guided acoustic wave wavefront so that the guided acoustic wave wavefront cannot be affected by scattering and distorted. Acoustic waves can propagate as expected in a curved waveguide based on this sub-wavelength acoustically transparent structure.

Description

technical field [0001] The invention belongs to the field of acoustic materials and relates to a sub-wavelength acoustic transparent structure, in particular to a parameter modulation method for eliminating the sub-wavelength structure of broadband reflected sound waves in a curved path. Background technique [0002] The acoustic properties of acoustic metamaterials designed with subwavelength units can greatly broaden the achievable range of material acoustic parameters, breaking through the limitations of natural materials. The extraordinary physical effects that can be realized by acoustic metamaterials have changed the traditional research concepts of various problems in the field of acoustics, and greatly improved people's ability to manipulate elastic waves. By designing structural units at the subwavelength scale, metamaterial parameters that do not exist in nature can be realized, allowing waves to reflect, refract, or propagate along a given path in a specific range...

AI Technical Summary

Problems solved by technology

In addition, in the past research on acoustic metamaterials, in order to simplify the fabrication, the impedance design was often neglected by scaling the ideal value to obtain the required refractive index, which will inevitably lead to impedance mismatch and affect the target wave manipulation effect.

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