中心棒哈特曼发声器声学特性研究

Research on acoustic characteristics of Hartmann acoustic generator with a central-stick

采用FW-H声模拟法,研究了中心棒的位置、长度和直径等因素对中心棒哈特曼发声器声学特性的影响,得出如下结论:无论中心棒置于谐振腔入口前端还是底部,只要中心棒一端处于气流入口到谐振腔入口段,哈特曼发声器就能产生较高的声压级;中心棒置于气流入口,且长度不超过喷流间距,会产生比普通哈特曼发声器更高的声压级;中心棒的半径有一个最佳值,数值模拟结果显示,不同半径中心棒哈特曼发声器声压级的大小顺序相应为:r=0.2mm、r=0.3mm、r=0.1mm、r=0.5mm,即半径r为0.2mm的中心棒哈特曼发声器产生的声压级较大,而半径r为0.5mm的声压级最较小;频谱分析发现,加中心棒会使哈特曼发声器的最大峰值频率变小。上述结论对中心棒哈特曼发声器的应用具有重要的指导意义。

Based on the method of FW-H acoustic model, the influences of three parameters on the acoustic characte- ristics of the Hartmann acoustic generator with a central-stick are studied. The three parameters are the position, the length and the diameter of the central-stick. The conclusions are as follows： the Hartmann generator can produce a higher SPL only if one of the ends of the central stick is placed in the gap between inlet and resonator, regardless of the position of the central-stick; the Hartmann generator can produce a higher SPL than the regular ones, just as the cen- tral-stick is placed in the inlet and within the gap between inlet and resonator; the magnitudes of SPL for different radii of the central-stick are sequenced correspondingly as r=0.2mm 〉 r=0.3mm 〉 r=0.1mm 〉 r=0.5mm, which means that the Hartmann generator with the central-stick of 0.2ram in radius can generate the maximal SPL, while the minimum appears in the case where the radius of the central stick is 0.5ram. By analyzing the spectrum, it is found that adding the central stick makes the maximal peak frequency decreases.