平行声屏障的陷波模态及其插入损失优化

为了改善平行声屏障的性能,该文基于有限元仿真的方法对其陷波模态和插入损失进行了研究。其中,陷波模态是平行声屏障的固有性质,与其几何参数有关。当陷波模态处于共振频率时,平行声屏障内部声场的声能量达到峰值,同时声波垂直入射到声屏障的顶端,使声影区的衍射声能也达到峰值,最终导致插入损失显著下降。该文还对3种优化平行声屏障插入损失的方法进行了分析。结果表明,楔形和扩散型声屏障可降低声波的多次反射效应对插入损失的影响,但是对陷波模态的改善较小;而吸声型声屏障有效地抑制了陷波模态对插入损失的不利影响,从而改善了平行声屏障的性能。

Wave-trapping modes and the Optimization of the Insertion Losses of Parallel Noise Barriers

The wave-trapping modes and insertion losses of parallel noise barrier are investigated in this paper, aiming to improve the performance of it. The wave-trapping modes are the inherent properties of parallel noise barrier and determined by the geometrical configuration of barriers. The sound energy within the parallel barrier will be highest when the wave-trapping modes are in resonance. In the meantime, the energy flux impinges normally on the top of the barrier, results in a peak diffractions in the shadow zone and remarkable drops of insertion losses. Three Optimization methods are analyzed in this paper as well. The results indicate that the wedge and diffuser structures that mounted on the inner surface of the barrier can reduce the negative influences of multiple reflections, but have little improvements on wave-trapping modes. While, the negative influence of the wave-trapping modes on the insertion losses are effectively confined by the absorptive barrier, hence improve the performance of parallel noise barrier.