切向流对微穿孔共振吸声结构声学性能的影响

切向流对微穿孔共振吸声结构声学性能的影响可以分成三类:(1)对小孔辐射声抗的影响;(2)对结构斜入射吸声性能的影响;(3)对消声通道消声性能的影响。根据声学基本理论,详细讨论这些影响,得到对应的理论分析公式。定性而言,若声波的传播方向与气流的运动方向一致,小孔外侧的辐射声抗、空腔声阻抗函数coth (ξ)的宗量ξ赋值和消声通道的消声系数都会减小;同时呈现多普勒效应,使得结构的吸声系数共振峰频率向低频移动。理论分析得到相应实验研究的支持。 

The effect of grazing mean flow on acoustical character of micro-perforated panel absorber

There are three effects of grazing mean flow on acoustical character of micro-perforated panel absorber(1) on radiation impedance of orifice,(2) on acoustical impedance of construction at sound wave angle incident,(3) on sound propagation property in duct lined construction.Based on acoustical fundamental principle,these effects were analyzed respectively,and relative formulas were derived.Some qualitative tendencies were shown that radiation impedance of orifice,value ofξin function coth(ξ) which estimates cavity impedance,and transmission loss in lined duct all will decrease with flow speed increases as well as the resonant frequency will move to lower frequency caused Doppler effect, when sound wave propagation direction is same with flow direction.The discussion was also supported by a relative experimental study.