针对目前水动力声学领域的孔腔流噪声研究大都基于单孔全开口模型的局限性，本文基于大涡模拟-声类比混合方法对局部开孔深腔体模型的孔腔流噪声发声机理进行研究。首先，对流场涡量、压强变化进行分析，得到涡结构的不断运动迁移和腔体孔壁后缘的碰撞发声构成的涡-声反馈是不同测点之间所测压强周期一致、相位不同的原因；其次，对不同测点的压强功率谱、空腔内声学模态频率进行分析，得到孔后壁上缘区域的压力脉动是局部开孔深腔体自持振荡发声的主要声源；最后，将所测声场特征线谱频率与经验公式的预测结果进行对比，验证了仿真结果的准确性。
Comparing to the former researches which focused on the model of cavity with a single full hole, this paper is based on the large eddy simulation and acoustic analogy theory to study on the flow noise mechanism produced by the deep cavity with a local hole. Firstly, according to the vorticity and pressure magnitude contours of the flow field, the vortex-acoustic feedback model is established to explain the situation that the exciting force of different measurement points have the same period but different phases. Secondly, by analyzing the power spectral of different measurement points' pressure and the Cavity Acoustic mode frequency, the pressure pulsation of the upper edge of the hole's back wall is confirmed as the main source of the flow noise produced by the local hole. Finally, the accuracy of the simulation results is verified by comparing the measured spectral characteristics of the sound field with the prediction results of the empirical formula.
2019,41(1): 26-32 收稿日期：2017-07-25
DOI：10.3404/j.issn.1672-7649.2019.01.005
分类号：TB533
作者简介：李荣华(1993-),男,助理工程师,研究方向为机械故障诊断
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