Shen Jie, Lu Zhiming, Wang Lian-Ping, Peng Cheng
School of Mechanics and Engineering Science, Shanghai Institute of Applied Mathematics and Mechanics, Shanghai University, Shanghai 200072, China.
Guangdong Provincial Key Laboratory of Turbulence Research and Applications, Center for Complex Flows and Soft Matter Research and Department of Mechanics and Aerospace Engineering, Southern University of Science and Technology, Shenzhen 518055, Guangdong, China and Department of Mechanical Engineering, 126 Spencer Laboratory, University of Delaware, Newark, Delaware 19716-3140, USA.
Phys Rev E. 2021 Aug;104(2-2):025109. doi: 10.1103/PhysRevE.104.025109.
In this paper, direct numerical simulations of particle-laden homogeneous isotropic turbulence are performed using lattice Boltzmann method incorporating interpolated bounce-back scheme. Four different particle-fluid density ratios are considered to explore how particles with different particle-fluid density ratios respond to the turbulence. Overall particle dynamics in the homogeneous isotropic turbulence such as the Lagrangian statistics of single particle and the preferential concentration of particles are investigated. Results show that particle acceleration and angular acceleration are more intermittent than velocity and angular velocity for finite-size particles with different particle-fluid density ratios. The preferential concentration of particles is investigated using radial distribution function and Voronoï tessellation, and the preferential concentration is more profound for particles with two intermediate particle-fluid density ratios. The Voronoï analysis indicates that the distribution of Voronoï cells satisfy the log-normal distribution better than the gamma distribution. The mechanism of preferential concentration is analyzed using the sweep-stick mechanism and drift mechanism. Results show that although a higher probability of having particles located near the sticky points is found, the sticky mechanism is very weak for large density ratios. The particle clustering is then found to be better qualitatively described by the drift mechanism.
在本文中，采用结合插值反弹格式的格子玻尔兹曼方法对含颗粒均匀各向同性湍流进行了直接数值模拟。考虑了四种不同的颗粒 - 流体密度比，以探究具有不同颗粒 - 流体密度比的颗粒如何响应湍流。研究了均匀各向同性湍流中的整体颗粒动力学，如单个颗粒的拉格朗日统计和颗粒的优先聚集。结果表明，对于具有不同颗粒 - 流体密度比的有限尺寸颗粒，颗粒加速度和角加速度比速度和角速度更具间歇性。使用径向分布函数和沃罗诺伊镶嵌法研究了颗粒的优先聚集，对于两种中等颗粒 - 流体密度比的颗粒，优先聚集更为显著。沃罗诺伊分析表明，沃罗诺伊单元的分布比伽马分布更符合对数正态分布。使用扫掠 - 黏附机制和漂移机制分析了优先聚集的机理。结果表明，尽管发现颗粒位于黏附点附近的概率较高，但对于大密度比，黏附机制非常微弱。然后发现颗粒聚集在定性上用漂移机制能更好地描述。
