Galton型高强气流声源的发声特性

文章介绍了一款带中心杆的Galton型气流声源,通过试验和数值模拟方法,研究了该声源发声特性、进气压力对声场分布的影响以及流体介质对发声特性的影响。研究发现,该声源稳定发声时,共鸣腔内压力场与流场均呈周期性变化;不同进气压力下,声场空间分布基本一致,具有较强的声指向性。共鸣腔后侧轴线处,声压级达到最大值,为153 dB,且声压级随角度的增加逐渐减小,并在共鸣腔正前方达到最小值。当进气压力增加时,不同方向的声压级增长情况各不相同,在0°处增幅最大,并随着角度的增加而减小,在180°处增幅最小。采用不同的流体介质时,发声振幅与频率不同,密度较小的水蒸气频率最高,且频率与声压振幅呈负相关,即频率越高声压振幅越小。

Acoustic characteristics of a high-intensity Galton whistle

A Galton whistle with a center bar is introduced and investigated.The numerical simulation method is used to study the changes of the pressure field and velocity field when the sound source works,the influence of the inlet pressure on the sound field distribution,and the effect of fluid medium on acoustic characteristics of sound source.The results show that the pressure field and flow field in the resonant cavity present periodic changes when the Galton whistle works stably.The sound source has strong sound directivity,and the sound field distribution under different intake the spatial distribution of pressures remains unchanged.The sound pressure level reaches a maximum value of 153 dB at the rear of the resonant cavity,decreases with increase of angle and reaches a minimum value at the front of the resonant cavity.As inlet pressure increases,the increases of sound pressure level in different directions are different.The increase at 0°is the maximum,then the sound pressure level decreases with increase of angle and reaches minimum at 180°.The acoustic characteristics(frequency and amplitude)vary with gas media.The sound source works at the highest frequency when low density steam is used as gas medium,and the variation of frequency and amplitude show an opposite trend,i.e.,the higher the frequency,the smaller the amplitude.