Flow and turbulent structures around simplified car models
Flow and turbulent structures around simplified car models
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DOI：
10.1016/j.compfluid.2014.03.013
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发表时间：
2014-06
影响因子：
2.8
通讯作者：
D. E. Aljure;O. Lehmkuhl;I. Rodríguez;A. Oliva
中科院分区：
文献类型：
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作者：
D. E. Aljure;O. Lehmkuhl;I. Rodríguez;A. Oliva
汽车外部空气动力学研究对于汽车整体效率和行驶稳定性非常重要，是成功汽车设计的关键要素。汽车几何形状上的流动显示出三维和不稳定的湍流特征。此外，钝体周围还存在涡流脱落、流动再附着和再循环气泡。这些现象极大地影响了升力和阻力系数，而升力和阻力系数分别是行驶稳定性和能源效率的基础。本研究的目的集中于评估不同的 LES 模型（例如 VMS 或 SIGMA 模型），并展示它们使用相对粗糙的网格捕获类车体中的大规模湍流结构的能力。为了实现这些目标，模拟了 Ahmed 和 Asmo 两种模型汽车几何形状周围的流动。这些通用钝体再现了真实汽车的基本流体动力学特征。首先，研究两种几何形状的流动并与实验结果进行比较，以验证数值结果。然后，使用不同的 LES 模型详细研究流动并比较两种几何结构中发现的结构。
External car aerodynamics study has great importance in overall car efficiency and ride stability, being a key element in successful automotive design. The flow over car geometries shows three dimensional and unsteady turbulent characteristics. Additionally, vortex shedding, flow reattachment and recirculation bubbles are also found around the bluff body. These phenomena greatly influence the lift and drag coefficients, which are fundamental for ride stability and energy efficiency, respectively. The aim of the present study is focused on the assessment of different LES models (e.g. VMS or SIGMA models), as well as to show their capabilities of capturing the large scale turbulent flow structures in car-like bodies using relative coarse grids. In order to achieve these objectives, the flow around two model car geometries, the Ahmed and the Asmo cars, is simulated. These generic bluff bodies reproduce the basic fluid dynamics features of real cars. First, the flow over both geometries is studied and compared against experimental results to validate the numerical results. Then, different LES models are used to study the flow in detail and compare the structures found in both geometries.