基于仿生的A柱-后视镜区域气动降噪研究

A Research on Aerodynamic Noise Reduction in A-pillar and Rear-view Mirror Areas Based on Bionics

在某SUV车型的A柱-后视镜区域建立了6种仿生模型,稳态计算采用SST k-ω湍流模型,瞬态计算采用大涡模拟(LES),探讨了流场和声场的气动特性。仿真与风洞实验结果对比表明,仿真的监测点压力系数与实验数据基本吻合,1/3倍频程声压级曲线也比较一致。仿真结果表明,6种仿生模型都起到了降低噪声的作用,尤其在人耳敏感的中高频域降噪效果更为明显。其中,仿生模型1(A柱凸起结构)与原模型相比,降低了涡流强度,对流线具有梳理作用。总声压级的分析表明,仿生凸起模型局部降噪效果明显,仿生凹坑模型降噪效果均匀。

Six bionic models are established in the A-pillar and rear-view mirror areas of a sport utility vehicle,and through steady calculations using SST k-ω turbulence model and transient calculations using large eddy simulation,the aerodynamic characteristics of flow field and acoustic field are investigated. The comparisons between simulation and wind tunnel test results show that the simulated pressure coefficients at measured points and 1/3 octave sound pressure level curve both well agree with test data. The results of simulation indicate that six bionic models all have good effects of noise reduction,especially in middle/high frequency regions,in which model 1( convex structure at A-pillar) plays a role of combing flow threads and results in a lower turbulence intensity,compared with the original model. The results of analysis on the overall sound pressure level reveal that convex bionic model has obvious effects in local noise reduction,while the concave one has a more uniform effect of noise reduction.