Zhou Haichao, Jiang Zhen, Yang Jian, Zhai Huihui, Wang Guolin
School of Automotive and Traffic Engineering, Jiangsu University, Zhenjiang 212013, China.
School of Automotive Engineering, Zhenjiang College, Zhenjiang 212000, China.
Appl Bionics Biomech. 2020 Mar 14;2020:4345723. doi: 10.1155/2020/4345723. eCollection 2020.
Unlike conventional pneumatic tires, the nonpneumatic tires (NPT) are explosion proof and simple to maintain and provide low rolling resistance. At high vehicle speeds, however, the complex airflow produced by the open flexible-spoke structure of NPT yields high aerodynamic noise, which contributes to sound pollution in the vehicular traffic environment. Inspired by the idea that a nonsmooth riblet structure can affect fluid flow and offer noise reduction, the analyses of the effect of the nonsmooth riblet surface on the aerodynamic noise of an NPT and noise reduction mechanism were presented in this paper. First, computational fluid dynamics (CFD) was used to analyze the surface pressure coefficient characteristics of a smooth flexible-spoke tire rolling at a speed of 80 km/h and subsequently validating the numerical simulation results by comparing them with published test results. Secondly, large eddy simulation (LES) and the Ffowcs Williams-Hawkings (FW-H) method were, respectively, used to determine the transient flow and far-field aerodynamic noise. Then, the mechanism of noise reduction was investigated using a vortex theory. Based on the vortex theory, the positions and strengths of noise sources were determined using the Lamb vector. Finally, according to the fluid boundary layer theory, a nonsmooth riblet surface was arranged on the surface of the spokes, and the influences of the riblet structure parameters, including size, position, and direction, on aerodynamic noise were analyzed. Based on the vortex theory, it was found that the nonsmooth riblet structure can reduce the Lamb vector, suppress the generation of flow vortices, decrease acoustic source strength, and effectively decrease noise up to 5.18 dB using the optimized riblet structure. The study results provide a theoretical basis for the structural design of a new low-noise NPT.
与传统充气轮胎不同，非充气轮胎（NPT）防爆且易于维护，滚动阻力低。然而，在车辆高速行驶时，NPT开放式柔性辐条结构产生的复杂气流会产生较高的气动噪声，这加剧了车辆交通环境中的噪声污染。受非光滑肋条结构可影响流体流动并降低噪声这一想法的启发，本文对非光滑肋条表面对NPT气动噪声的影响及降噪机理进行了分析。首先，使用计算流体动力学（CFD）分析了以80 km/h速度滚动的光滑柔性辐条轮胎的表面压力系数特性，随后将数值模拟结果与已发表的测试结果进行比较以验证其有效性。其次，分别使用大涡模拟（LES）和Ffowcs Williams-Hawkings（FW-H）方法确定瞬态流动和远场气动噪声。然后，利用涡旋理论研究降噪机理。基于涡旋理论，使用兰姆矢量确定噪声源的位置和强度。最后，根据流体边界层理论，在辐条表面布置非光滑肋条表面，并分析肋条结构参数（包括尺寸、位置和方向）对气动噪声的影响。基于涡旋理论发现，非光滑肋条结构可降低兰姆矢量，抑制流动涡旋的产生，降低声源强度，使用优化后的肋条结构可有效降低噪声达5.18 dB。研究结果为新型低噪声NPT的结构设计提供了理论依据。
