切向流条件下穿孔板声学性能脉冲法测量技术

Acoustic Performance Measurement of Perforated Plate Using Impulse Method in the Condition of Grazing Flow

采用脉冲测量法,通过在管道内生成波形良好的可控脉冲,实现切向流条件下的穿孔板声学性能宽频带测量。研究切向流对穿孔板声阻抗的影响特征。研究结果表明,在1 500 Hz以下频段,穿孔板的声阻率随流速增大,而在1 500~4 000 Hz频段,声阻率随流速减小;切向流条件下的共振峰向高频偏移,吸声频带加宽。

A broadband method was proposed by using impulse method. The acoustic performance of a perforated plate in the condition of grazing flow was measured by generating a pulse in the pipe with controllable waveform. The measurement results show that the acoustic resistance ratio of perforated plate increases gradually with the flow-rate increasing for the Mach number below 1 500 Hz, while in the frequency range from 1 500 Hz to 4 000 Hz, the acoustic resistance ratio tends to decrease with the flow-rate increasing, and the resonance peak moves to the high frequency side under the grazing flow and the frequency band of the perforated plate for sound-absorption becomes winder.