壁湍流等动量区对惯性颗粒分布的影响

对摩擦雷诺数为1000、颗粒Stokes数为1.0的含颗粒槽道湍流进行了直接数值模拟,采用高斯函数叠加法提取了等动量区的模态速度,对各等动量区内的颗粒分布进行了分析。发现在高动量的核心区,颗粒平均浓度高于非核心区,而浓度脉动低于非核心区。在等动量区界面上,流体速度和颗粒浓度变化剧烈,展向涡结构的出现导致了局部颗粒浓度较低。在等动量区的界面以下,在较高的壁面法向位置,存在大尺度的浓度幅值低而浓度脉动高的结构,其等值线分布与核心区/非核心区界面一致。

Influence of uniform momentum zone on inertial particle distribution in wall turbulence

Direct numerical simulation was performed to particle-laden turbulent channel flow at the friction Reynolds number of 1000 and particle Stokes number of 1.0.Superposed Gaussian functions were adopted to extract the modal velocity of uniform momentum zone(UMZ).The particle distributions in each UMZ were studied.In the quiescent core region with large fluid momentum,the particle concentration is higher and the concentration fluctuation is lower than those in the non-core region.Distinct abrupt change of velocity and particle concentration exists at the UMZ interface.The presence of spanwise vortical structures leads to the local minimum value of particle concentration.Beneath the UMZ interface at high wall-normal position,there exists large-scale regions with low concentration magnitude and high concentration fluctuation.The contour of the concentration is in consistent with the shape of the turbulent/non-turbulent interface.