Airfoil trailing-edge noise prediction based on CFD/CAA coupled boundary method

基于CFD/CAA耦合边界方法的翼型尾缘噪声预测

¹ School of Marine Science and Technology, Northwestern Polytechnical University, Xi'an 710072, China
² Xi'an Precision Machinery Researh Institute, Xi'an 710077, China
³ School of Aeronautics, Northwestern Polytechnical University, Xi'an 710072, China

Received: 9 June 2022

Abstract

Flow-induced noise hybrid prediction method based on sound wave boundary condition is an effective numerical method to deal with a flow-induced noise problems of complex configuration. This method can not only finely simulate the sound source, but also analyze the noise propagation characteristics. In this paper, numerical methods such as space-time discrete scheme and boundary conditions involved in discrete solution of acoustic perturbation equations(APE) are developed, and strategies such as adding buffer layer are proposed to improve divergence caused by numerical discontinuity at the junction of sound source region and propagation region, so as to establish a high-precision flow-induced noise hybrid method. In order to study the rationality of flow-induced noise hybrid method, the numerical simulation of acoustic radiation at the trailing edge of NACA0012 airfoil in BANC experiment was carried out. Compared with the results of sound field solved by large eddy simulation method, the analysis shows that the high-precision flow-induced noise hybrid method based on sound wave boundary conditions can predict the spatial sound field distribution with high precision and directly reflect the interaction between sound waves. Compared with the results of large eddy simulation, the error of sound pressure level is less than 2 dB, and the noise directional distribution trend is consistent.

摘要

基于声波边界条件的流致噪声混合预测方法是一种处理复杂构型声学问题的数值手段。该方法可进行声源的精细化模拟, 准确获得噪声的传播特性。发展了声扰动方程离散求解中所涉及的时空离散格式及边界条件等数值方法, 提出通过添加缓冲层等策略以改善声源区与传播区交界处数值间断引起的发散问题, 以建立高精度流致噪声混合预测方法。为了研究混合方法的准确性, 以BANC试验中的NACA0012翼型为研究对象, 开展了翼型尾缘的声辐射数值模拟研究分析。通过与大涡模拟方法所求解的声场结果进行对比, 验证了基于声波边界条件的高精度流致噪声混合预测方法可准确预测空间声场分布, 并直观反映声波与声波之间的相互作用现象。与大涡模拟结果相比, CFD/CAA方法总声压级误差不超过2 dB, 噪声指向性分布趋势一致。