存在热浮力的剪切湍流中颗粒近壁运动的大涡模拟

采用基于动力学亚格子模型和热通量模型的大涡模拟方法，结合Lagrange粒子追踪技术，数值研究了存在热浮力作用的剪切湍流中细颗粒群的输运特性.一方面探讨在槽道剪切湍流中不同热分层效应与粒子输运的动态关联性，以及不同Stokes数的细颗粒在同一分层湍流环境下的浓度分布；另一方面探讨动量和热量耦合作用下影响粒子迁移、扩散和沉积的不同因素.此外，基于一些典型计算结果，探讨了稳定和不稳定分层对颗粒运动各向异性程度的影响，研究了不同颗粒的平均速度、脉动强度的统计特征量以及与湍流流场之间的相关性，并对颗粒在槽道不同区域的体积浓度分布和局部积聚现象进行了分析.

Large Eddy Simulation of Particle Motion in Shear Turbulent Flow Due to Thermal Buoyancy

The behavior of dilute dispersion of particles in a stratified channel flow is investigated with large eddy simulation.The three-dimensional Navier-Stokes and energy equations under the Boussinesq approximation are numerically solved using a fractional-step method based on high-order accurate temporal schemes.The Lagrangian tracking approach is used to describe the dynamics of particles.The objectives of this study are to deal with the effect of the thermal buoyancy on the behavior of particles in the thermally stratified turbulent channel flow and examine particle concentrations under the stratified turbulent environment.In the present study,some typical cases are computed.To depict the effect of the thermal stratification on the particles transport,the mean value and fluctuation of resolved velocities of pafiicles,as well as some typical instantaneous velocity fluctuation patterns are analyzed.Numerical results provide the characteristics of particle concentrations under different Stokes numbers.