非定常空化流致噪声的数值模拟

发布时间：2018-11-21 13:11

【摘要】：采用计算流体力学与声学边界元法相结合对绕水翼非定常空化流动的负载噪声进行计算,同时基于球空泡理论的脉动体积法预测了空泡噪声.研究结果表明:无空化发生时,负载噪声以低频线谱特性为主,声波基频与尾涡脱落频率基本一致,线谱峰值发生于低阶谐频处;空化发生时,相比于负载噪声的线谱成分,连续谱增强较为显著,且负载噪声的总声压级相比无空化时有所增大,并且空泡噪声成为最主要噪声源,辐射噪声频谱呈宽谱特性;空泡噪声功率谱密度的第一和第二个峰值频率分别与空化脱落频率和尾涡脱落频率相对应,而空泡噪声的声能量密度集中在相对较高的频带范围内,这可能是由于云状空化阶段空穴尾部伴随着多尺度的空化泡生长脱落行为所致.
[Abstract]:The computational fluid dynamics (CFD) and acoustic boundary element method (BEM) are used to calculate the load noise of the unsteady cavitation flow around the hydrofoil, and the cavitation noise is predicted based on the pulsating volume method of the spherical cavitation theory. The results show that when there is no cavitation, the low frequency linear spectrum is the main characteristic of the load noise, the fundamental frequency of acoustic wave is basically the same as the frequency of wake vortex shedding, and the peak value of the line spectrum occurs at the low order harmonic frequency. When cavitation occurs, compared with the linear component of the load noise, the continuous spectrum increases significantly, and the total sound pressure level of the load noise increases compared with that without cavitation, and the cavitation noise becomes the main noise source, and the spectrum of radiation noise is broad spectrum characteristic. The first and second peak frequencies of cavitation noise power spectrum density correspond to cavitation shedding frequency and wake vortex shedding frequency respectively, while the acoustic energy density of cavitation noise is concentrated in a relatively high frequency band. This may be due to the cavitation bubble growth and shedding at the end of the cloud cavitation stage.
【作者单位】：北京理工大学机械与车辆学院;
【基金】：国家自然科学基金资助项目(51306020)
【分类号】：TV136

【相似文献】