A Calculation Method for Acoustic Transmittance and Acoustic Transmission Loss of Rectangular Openings

Abstract

The invention discloses a rectangular opening sound transmission rate and sound transmission loss computing method. The method comprises, firstly, defining a rectangular-opening coordinate system, and establishing force balance formulas of both cross sections of the opening and the sound transmission matrixes at both ends of the opening; secondly, utilizing the properties of sound radiating impedance of vibration of air layers at both ends of the opening to achieve computation of the sound transmission rate of a rectangular opening single-level mode under the condition of parallel sound wave incidence; thirdly, superpositioning the sound transmission rate of every level of mode to obtain the sound transmission rate of the rectangular opening; fourthly, integrating incident angles to obtain the sound transmission rate of the rectangular opening under the condition of scattered sound field incidence; lastly, calculating the sound transmission losses of the rectangular opening under the condition of the scattered sound field incidence through a relation between sound transmission losses and sound transmission rates. The rectangular opening sound transmission rate and sound transmission loss computing method can be used for computing the sound transmission rates or the sound transmission losses of one or more certain levels as well as computing total sound transmission rates or total sound transmission losses, thereby greatly improving the computing flexibility, and meanwhile, by omitting the influence of the very small sound radiating impedance of both a part of real parts and a part of imaginary parts, greatly improves the calculating speed.

Description

technical field [0001] The invention relates to a method for calculating the sound transmission rate and sound transmission loss of a rectangular opening on a wall in the field of noise in the specialty of physics, in particular to a method capable of calculating the shape of a rectangular opening on both sides of the wall. Calculation method of acoustic transmission rate and acoustic transmission loss of openings with finite depth and need to consider high-order wave components (need to consider high-order modes). Background technique [0002] Openings are mainly divided into large openings, small and medium holes, and micropores. [0003] For micropores, academician Ma Dayou, a famous Chinese scholar, and his research team have conducted in-depth research, and many domestic and foreign scholars have also conducted a lot of research. [0004] For small and medium holes, because their size is not very large, the frequency range of the research is often below the cut-off fre...

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Problems solved by technology

[0006] These methods have certain effects and have their own characteristics when calculating specific types of openings, but they also have certain limitations

For example, the acoustic transmission loss calculation formula derived based on the plane wave theory can only be used to calculate the acoustic transmission loss below the cutoff frequency of the plane wave

Although the modal-based acoustic transmission loss calculation formula can calculate the total acoustic transmission rate and acoustic transmission loss, it cannot calculate the acoustic transmission rate and acoustic transmission loss of the opening in any one or multiple modes, and when the frequency is very High, when the number of modes is high, the calculation speed is slow

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