A柱涡动力学特性随前窗倾角变化研究

An Investigation of Changes in APillar Vortex Dynamics with Windshield Inclination

摘要:

采用风洞试验和数值计算的方法，通过Dihedron模型研究了前窗倾角对A柱涡动力学演化的影响.时均阻力和表面压力通过风洞试验获得，采用分离涡模拟（DES）捕捉A柱涡拓扑结构的细节特征.通过风洞试验的结果验证了DES结果的有效性.DES的结果描述了A柱涡涡破裂现象.随着前窗倾角的变化，A柱涡表现为不同的结构形态，这主要是由主涡中涡量平衡决定的.试验和数值结果均表明,随前窗倾角增大，Dihedron模型的阻力增加.讨论了纵向涡的破裂趋势和潜在的减阻方案.最后，强调了模型壁面的动力学特性及其对车内噪声的影响.

关键词:A柱涡;汽车前窗倾角;涡破裂;涡量平衡;Dihedron模型;分离涡模拟

Abstract:

The influence of windshield inclination on the dynamics evolution of the Apillar vortex produced by Dihedron models is investigated both experimentally and numerically. The timeaveraged aerodynamic drag and surface static pressure are captured by wind tunnel experiment, and detachededdy simulation (DES) is employed to characterize the details of the topology of Apillar vortex. The DES results are validated by experimental results both herein and from the reference paper. The breakdown phenomenon of Apillar vortex is described by the DES results. The Apillar vortex demonstrates different flow patterns with windshield inclination variation, which is dominated by the vorticity balance theory in the primary vortex. Both experimental and numerical results show that the aerodynamic drag of Dihedron models increases when enlarging the windshield slant angle. The breakdown trend of longitudinal vortexes is discussed and a potential drag reduction scheme is visualized. Finally, wall dynamics of Dihedron models and its influence on the incabin noise are emphasized.

Key words:Apillar vortex; automotive windshield inclination; vortex breakdown; vorticity balance; Dihedron model; detachededdy simulation