Prediction of aerodynamic noise reduction by using open-cell metal foam
Prediction of aerodynamic noise reduction by using open-cell metal foam
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DOI：
10.1016/j.jsv.2011.11.016
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发表时间：
2012-03
影响因子：
4.7
通讯作者：
Hanru Liu;Jinjia Wei;Z. Qu
中科院分区：
文献类型：
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作者：
Hanru Liu;Jinjia Wei;Z. Qu
随着高速列车运行速度的不断提高，列车空气动力学噪声相对于轮轨噪声更为突出，影响了铁路沿着的人居环境和乘坐舒适性。本文初步探讨了采用开孔泡沫金属覆盖层降低受电弓典型断面圆柱绕流产生的低马赫数气动噪声的可行性。计算了有、无泡沫金属的圆柱体的气动噪声。采用二维大涡模拟（LES）与Ffowcs Williams-Hawkings（FW-H）方程相结合的混合方法。计算得到的斯特劳哈尔数、时均阻力系数、底压和总声压级与实验数据吻合较好。研究了泡沫金属孔隙率、孔密度、覆盖层厚度以及列车运行速度对空气动力噪声的影响，并对流场进行了详细的比较。数值结果表明，作为一种被动方案，高孔隙率开孔泡沫金属可以改变流动，调节旋涡脱落频率，并使尾迹规则化，从而显著降低气动噪声。研究结果可为该材料的气动噪声控制提供参考。
As the speed of high-speed train (HST) increases continuously, aerodynamic noise has become more remarkable compared with the wheel/rail noise, which affects the inhabited environment along the railway and the riding comfort. This paper preliminarily investigates the feasibility of using open-cell metal foam covering layer to reduce the low Mach number aerodynamic noise generated by the flow around a circular cylinder which is the typical section of pantographs. The aerodynamic noises radiated from the circular cylinder with and without metal foam are calculated. The hybrid method combining two-dimensional large eddy simulation (LES) with Ffowcs Williams–Hawkings (FW–H) equation is employed. The calculated Strouhal number, time-averaged drag coefficient, base pressure and overall sound pressure level agree well with some available experimental data. Then, the influences of metal foam porosity, pore density, thickness of covering layer and the speed of train on the aerodynamic noise and the aerodynamic forces are investigated, and some detailed comparisons of flow field are made. The numerical results indicate that as a passive scheme, the open-cell metal foam with high porosity can modify the flow, adjust the vortex shedding frequency and regularize the wake, leading to a significant reduction of aerodynamic noise. The results are expected to provide useful information for the control of aerodynamic noise using this new material.