PDF(Pubmed)
Abstract：
The high-intensity low-frequency acoustic sources have essential applications in acoustic biological effects research, airport bird repelling, and boiler ash removal. However, generating high-intensity low-frequency acoustic waves in open space is difficult. In this paper, a low-frequency acoustic generator with a resonant cavity used to enhance the acoustic intensity in open space was developed, which is an aerodynamic acoustic generator to radiates a high-intensity acoustic wave of 52Hz. Some experiments were carried out to measure this generator\'s internal flow field and radiated acoustic field characteristics, including the propagation characteristics at 100m. The experimental results show that the resonant enhancement effect is presented near the predetermined resonance frequency, and the enhanced value is about 4dB. The acoustic intensity for 52Hz at 1m position is 124dB. By combining the Helmholtz resonator with the airflow modulator, the airflow resonance in the resonator enhances the air pressure pulsation inside the chamber and increases the disturbance of acoustic radiation to the air. So as to improve the sound intensity and radiation efficiency in the low-frequency range.
摘要：
高强度低频声源在声学生物效应研究中有着重要的应用,机场鸟类排斥，锅炉除灰。然而,在开放空间中产生高强度低频声波是困难的。在本文中,开发了一种具有谐振腔的低频声发生器，用于增强开放空间中的声强，这是一个空气动力声发生器辐射的高强度声波52Hz。进行了一些实验来测量该发电机的内部流场和辐射声场特性，包括100m处的传播特性。实验结果表明,谐振增强效应在预定谐振频率附近呈现,增强值约为4dB。在1m位置52Hz的声强为124dB。通过将赫姆霍兹共振器与气流调节器相结合，谐振器中的气流谐振增强了腔室内的气压脉动，并增加了声辐射对空气的干扰。从而提高低频范围内的声强和辐射效率。
