分离涡模拟和非线性声学方法求解腔体气动噪声对比分析  

Comparison of NLDE and DES Methods for Prediction of Cavity Aerodynamic Noise

作　　者：张群峰[1] 闫盼盼[1] 黎军[2] 

机构地区：[1]北京交通大学土木工程学院,北京100044 [2]中国航空工业集团公司沈阳飞机设计研究所,辽宁沈阳110035

出　　处：《兵工学报》2016年第6期1096-1103,共8页Acta Armamentarii

基　　金：国家自然科学基金项目(11172283)

摘　　要：超声速条件下内埋式弹舱通常存在明显的自持振荡现象并产生强烈的气动噪声。分别利用分离涡模拟(DES)方法和求解非线性脉动方程组的非线性声学方法,对来流马赫数为2.0条件下,长度与深度比为5.88的开式空腔进行了数值模拟。计算结果表明,非线性声学方法得到的各模态声压级量级与实验结果符合较好,而DES方法得到的结果偏小,幅值在5 d B左右;DES方法求得的各模态频率与实验吻合较好,而非线性声学方法求得的频率有一定偏差。产生这些差别的原因是DES方法能较为准确地捕捉噪声源,而非线性声学方法由于耗散小而能较好地模拟噪声传播过程。从两种方法所需的计算资源对比表明:DES方法要求较密的网格和较小的时间步,需要耗费较多的计算资源;非线性声学方法采用人工合成湍流的方法来模拟小尺度脉动,可以选择较粗的网格和较大的时间步从而节约计算资源。Cavity in the supersonic flow has an obvious self-sustained pressure oscillation which causes a fierce aerodynamic noise. An open cavity which length-to-depth ratio is 5. 88 is simulated to predict the noise under the condition of Ma = 2. 0. Both detached eddy simulation（ DES） method and nonlinear acoustic method for solving the non-linear disturbance equations（ NLDE） method are used. The results show that NLDE method performs better in predicting the sound pressure level（ SPL）,and the predicted results are in agreement with the experimental results while the peak values of cavity tones obtained by DES method are 5 d B lower than those obtained by NLDE method. However,the DES method is more accurate in predicting the mode frequencies. The reason for these differences is that the DES method can capture the noise source more accurately,and NLDE method can simulate the noise propagation better.The comparison on computing resource indicates the DES method needs high resolution mesh and small time step which leads to high cost of computing resources,and the NLDE method models the fine scale turbulent motions by synthetic turbulence on coarse mesh and large time step,thus reducing the need forcomputing resource significantly.

关 键 词：兵器科学与技术 开式腔体 气动噪声 声压级 分离涡模拟 非线性脉动方程组 

分 类 号：V211.3[航空宇航科学与技术—航空宇航推进理论与工程]