Sound propagation over a barrier with realistic wind gradients. Comparison of wind tunnel experiments with GFPE computations

摘要

In order to study the effect of meteorology on sound diffraction by barriers, the results of scale-model experiments performed in a wind tunnel are compared with Green's Fast Parabolic Equation (GFPE) calculations for downwind refraction. Precise measurements of the airflow and turbulence around the barrier yield data that provide a good test for the GFPE. In the GFPE calculation, the medium is approximated as a series of range independent sections. The agreement between measured and calculated results is quite good. The results also show that barrier effect is not totally cancelled by downwind conditions. In addition, the comparison of experimental results with GFPE calculations with simpler range independent sound speed profiles shows that simple schemes using a constant sound speed gradient is efficient as well. Moreover, a method to implement a von Karman turbulence spectrum in GFPE is applied and the results are compared to measurements. [References: 22]