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在湍流状态下,利用计算流体力学(CFD)技术,对一系列布置不同尺寸顺流向脊状结构的表面进行了数值模拟。模拟过程采用Reynolds应力方程湍流模型,并且编制程序设定了充分发展的湍流入口边界。通过与光滑表面比较发现,脊状结构附近产生的流向涡是脊状表面减阻或者增阻的重要原因。流向涡改变了近壁面流场结构,引起了边界层近壁区雷诺应力和壁面剪应力的变化,脊状表面也因此出现了减阻或者增阻的现象。
In the turbulent regime, a series of surfaces with different sizes of downflow to ridge structures were numerically simulated using Computational Fluid Dynamics (CFD) technique. The simulation process uses the Reynolds stress equation turbulence model and the programming procedure sets the well-developed turbulent inlet boundary. By comparing with the smooth surface, it is found that the flow vortex generated in the vicinity of the ridge structure is an important reason for the drag reduction or resistance increase of the ridge surface. The flow vortex changes the structure of the flow near the wall and causes the Reynolds stress and the wall shear stress in the near wall of the boundary layer. The ridge surface also has the phenomenon of drag reduction or resistance increase.