基于渗流FW-H方法的水下回转体空泡流噪声特性数值模拟  

NUMERICAL STUDY ON CAVITATING FLOW NOISE CHARACTERISTICS OF UNDERWATER AXISYMMETRIC BODY UPON POROUS FW-H METHOD

作　　者：高健 胡常莉[1] 周毅 程诚[1] GAO Jian;HU Chang-li;ZHOU Yi;CHENG Cheng(School of Energy and Power Engineering,Nanjing University of Science and Technology,Nanjing,Jiangsu 210094,China)

机构地区：[1]南京理工大学能源与动力工程学院,江苏南京210094

出　　处：《工程力学》2024年第11期238-247,共10页Engineering Mechanics

基　　金：国家自然科学基金项目(52076108)。

摘　　要：空泡流噪声对水下回转体的隐身性能和操纵稳定性具有重要影响。采用大涡模拟结合渗流FW-H方程对平头和90°锥头两种回转体空泡流噪声特性进行了数值模拟,分别分析了两种头型回转体在无空化和空化数为0.8的条件下噪声频谱特性和声指向性。通过与实验结果对比,验证了所采用数值方法的可靠性。研究表明:绕流回转体的空穴演化规律与其辐射噪声特性之间关系密切,空泡体积与声压变化存在高度负相关性,空泡局部断裂溃灭会产生强烈的声压脉冲,空泡聚集再融合阶段,两者声压又会逐渐降低。空泡流噪声的峰值频率与空泡脱落频率相对应,垂直于来流方向上由于回转体周向存在空泡而在高频段产生明显宽带峰。此外,两种头型回转体的声指向性在无空化时呈偶极子特性,而在空化条件下呈球形单极子特性。相比之下,平头回转体空穴尺度更大且其变化加速度更大,引起的瞬时噪声更强,其远场平均总声压级比锥头的大8.7 dB。The cavitating flow noise has an important influence on the stealth performance and maneuvering stability of an underwater axisymmetric body.The large eddy simulation combined with porous FW-H method is used to simulate the noise characteristics of cavitating flows around two axisymmetric bodies with a blunt head and a conical head of 90°.The noise spectrum characteristics and sound field directivity for these two bodies are analyzed under the conditions of non-cavitation and a cavitation number of 0.8,respectively.The numerical method reliability is verified upon the experimental results.The research shows that the time-evolution process of cavities has a close relationship with the noise characteristics.There is a high negative correlation between the vapor volume and sound pressure.The immense pulse of sound pressure is found during the break-off and the collapse process of local cavities.At the gathering and merging stage,the sound pressure can gradually decrease.The noise peak frequency agrees well with the cavity shedding frequency.In the direction perpendicular to the incoming flow,an obvious broadband peak occurs in the high frequency band due to the cavities around the bodies.In addition,the sound field directivity respectively presents the dipole characteristic for non-cavitation and monopole characteristic for cavitation.By contrast,the cavity scale around the blunt-headform axisymmetric body is larger and its variation acceleration is larger too,and the instantaneous noise is stronger.Compared with that of the cone-headform body,the average total sound pressure level at far sound field of the blunt-headfrom body is 8.7 dB higher.

关 键 词：回转体 噪声 空泡演化 频率 声指向性 

分 类 号：O427[理学—声学]