ABSTRACT

Turbulent flow over bottom-mounted ribs is investigated using three-dimensional (3D) Spalart-Allmaras Delayed Detached-Eddy Simulations (SADDES). The ribs are subjected to a boundary layer flow with a thickness of δ/H=0.73 at Re=1∗106(Re=U∞H/ν), where U∞ is the free stream velocity, H is the rib height and ν is the fluid kinematic viscosity. Mesh and time step convergence studies are conducted to determine the grid and time step resolution. The numerical model is validated against the previous published experimental data and numerical results. The effects of different ribs geometries on drag and lift coefficients, the wake flow structures, and the dominant frequencies are discussed. Dominant flow features are investigated by carrying out Proper Orthogonal Decomposition (POD) and quadrant analysis of velocities and pressure in the wake flow.

摘要

使用三维（3D）Spalart-Allmaras延迟分离涡流模拟（SADDES）研究了底部安装肋骨上的湍流。肋在Re = 1 * 106（Re =U∞H/ν）时经受厚度为δ/ H = 0.73的边界层流，其中U∞为自由流速度，H为肋高度，ν是流体运动粘度。进行网格和时间步收敛研究以确定网格和时间步分辨率。数值模型已针对先前发布的实验数据和数值结果进行了验证。讨论了不同的肋骨几何形状对阻力和升力系数，尾流结构和主导频率的影响。通过进行适当的正交分解（POD）以及尾流中的速度和压力的象限分析，研究了主要流动特征。