不可压缩空腔流振荡模式和声学特性研究  

Investigation on the oscillation mode and the acoustic characteristics of incompressible cavity flow

作　　者：陈灿[1] 吴方良[1] 李环[1] 张志国[2] 刘聪尉 

机构地区：[1]中国舰船研究设计中心,武汉430064 [2]华中科技大学船舶与海洋工程学院,武汉430074

出　　处：《水动力学研究与进展（A辑）》2015年第3期272-278,共7页Chinese Journal of Hydrodynamics

摘　　要：不可压缩空腔流的振荡模式和声学特性研究近年来成为研究的热点,而空腔的长深比(L/H)是影响空腔流振荡模式和声学特性最重要的参数之一。该文在五类不同的长深比(L/H=4:1、2:1、1:1、1:2和1:4)下,来流分别为2 m/s和4 m/s时,对比分析了空腔流的振荡模式和流动特性。另外,使用大涡模拟(LES)声类比混合方法预测不同情况下空腔的声学特性,先用LES计算所得到的空腔非定常流场建立声源项,然后使用Ffowcs Williams-Hawkings(FW-H)声类比来预测远场噪声,比较不同长深比空腔的声学特性。计算结果表明,对L/H=4:1的空腔流动,振荡模式是尾流模式;而在L/H=2:1的情况下,振荡模式是剪切层模式;当L/H减小到一定程度时,将不会发生振荡。空腔的主要噪声源是空腔流激振荡,低频下声源声压级较大;空腔的总噪声级具有指向性。Investigation on the oscillation mode and acoustic characteristics of incompressible cavity flow has become a research hotspot in recent years. The cavity length depth ratio（ L/ H） is one of the most important parameters of the cavity flow oscillation mode and the acoustic characteristics. Based on the five different length depth ratio（ L/ H = 4：1, 2：1, 1：1, 1：2 and 1：4）cavities, this study analyzes the oscillation mode and acoustic characteristics of cavity by contrast. In addition, LES acoustic analogy mixed method is used to predict the acoustic characteristics of the cavity under different conditions. The computed result of cavity unsteady flow is used to establish the sound source. Then Ffowcs Williams-Hawkings（FW-H） acoustic analogy is used to predict the far field noise and compare the acoustic characteristics of five kinds of cavity. Calculative results show that the oscillation mode of cavity is wake mode when L/ H = 4：1, while the oscillation mode of cavity is the shear layer oscillation when L/ H = 2：1. And the oscillation will not occur when L/ H reduces to a certain degree. Most of hydrodynamic noise sources of cavity are flow-induced oscillation. The sound pressure level of sound sources in low-frequency domain is larger. The overall sound pressure level has the radiation directivity.

关 键 词：空腔流 深腔 大涡模拟 声类比 振荡模式 

分 类 号：O352[理学—流体力学] O427[理学—力学]