The problem of noise exposure from stationary engineering equipment remains relevant for urban development and industrial sites. One of the ways to solve it is by shielding, that is, by installing a barrier between the noise source and the protected area. Solid screens are often used for highways and railways, but such structures are not applicable for equipment that requires a constant supply of air. In these cases, blown noise shields are required, combining noise reduction with air exchange. The object of the study is a screen made of thin plates arranged in parallel with a constant pitch. The acoustic properties of such a structure were investigated by numerical experiment in the Comsol Multiphysics software package. The propagation of sound from a point source through a periodic array to a point (area) behind the screen is modeled. The "Efficiency" parameter was selected to evaluate the noise shield. The effectiveness of the screen is understood as the difference in sound pressure levels at the design point without and with a protective shield. The analysis of the influence of the geometric characteristics of the screen (the length of the plates and the distance between them) on the efficiency of the screen for geometric mean frequencies is performed. The results are presented in the form of thermal tables: the acoustic efficiency value is compared for each combination of geometric parameters. It is shown that reducing the ratio of the length of the plates to the gap between them increases the efficiency of the screen. With an optimal ratio of geometric parameters, sound attenuation of the order of 11 dB is achieved. The obtained dependencies can be used in the design of blown noise barriers for engineering equipment
Dolger et al. (Thu,) studied this question.