基于线阵列的湍流边界层壁面脉动压力波数-频率谱模型实验研究

Experimental study of the turbulent-boundary-layer wall pressure fluctuation wavenumber-frequency spectrum models using linear array

湍流边界层壁面脉动压力波数-频率谱建模是流动噪声领域十分关注的问题。研究首先总结归纳了近60年来的11种波数-频率谱预测模型,并按照模型的理论基础和表达形式划分为四类:Corcos类模型、不可压缩理论基模型、可压缩理论基模型和其他类模型。然后,开展声学风洞线阵列实验并对各预测模型进行展向方向波数积分,分别获得了流向方向的湍流边界层壁面脉动压力波数-频率谱实验测量结果与模型预测结果。最后,按照Corcos类模型与非Corcos类分别开展对比研究,分析研究了四类11种模型预测能力。研究结果表明:线阵列测量可以有效获得流向方向的波数-频率谱,并可用于校验各预测模型精度;在6个Corcos类模型选取时,需根据所关心的频率、波数范围及表达式计算复杂程度选取合适的预测模型;5个非Corcos类模型能够直接预测波数-频率谱,不需要自谱模型输入,较Corcos类模型具有较大优势,其中综合考虑Chase I模型最优,Chase II具备声学区边界预测能力。

Wavenumber-frequency spectrum modeling of wall pressure fluctuation has been the focus of the flow-induced noise in turbulent boundary layers.This study first summarized 11 models in the last six decades,classified into four groups,i.e.,Corcos-type,incompressible,compressible,and others.The performance of these models,further classified into Corocos-type and non-Corcos-type,was then examined by comparing their prediction with the experimental measurement using a linear array in an aeroacoustic wind tunnel.Results show that the linear array can measure the streamwise wavenumber-frequency spectrum correctly and,therefore,can be used to evaluate the accuracy of prediction models.The Corcos-type models have to be chosen based on the interested frequencies,wavenumbers,and the formula's complexity.The non-Corcos-type models can directly predict the wavenumber-frequency spectrum without the self-spectrum input,an advantage over the Corcos-type.Specifically,Chase-I model has the best ovserall performance;Chase-II can predict the acoustic-affected area.