Calculation of sound reduction by a screen in a turbulent atmosphere using the parabolic equation method

Results from applying a Crank–Nicholson parabolic equation method (CNPE) are presented in situations with a thin screen on a hard ground in a turbulent atmosphere, and with the acoustic source at ground level. The results are evaluated by comparison with Daigle’s model, which uses the sound scattering cross section by Tatarskii together with diffraction theory. The results show a fairly good agreement for situations where the receiver is above ground, thus indicating that both methods are applicable to the problem. When the receiver is at ground level the two methods lead to significant differences in insertion loss since only the PE method predicts that turbulence causes an increased sound level in the case without a screen. For the situations considered in the paper a turbulent atmosphere shows a significant influence on sound reduction by screens. [This work is financially supported by the Swedish Environmental Protection Agency (SNV) and the Swedish Transport and Communications Research Board (KFB).]

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