Fully resolved simulations of colliding monodisperse spheres in forced isotropic turbulence
Fully resolved simulations of colliding monodisperse spheres in forced isotropic turbulence
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DOI：
10.1017/s0022112004001326
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发表时间：
2004-10
影响因子：
3.7
通讯作者：
A. T. Cate;J. Derksen;L. Portela;H. V. D. Akker
中科院分区：
文献类型：
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作者：
A. T. Cate;J. Derksen;L. Portela;H. V. D. Akker
提出了悬浮在持续湍流场中的颗粒的完全解析模拟。为了求解纳维-斯托克斯方程，使用了格子-玻尔兹曼方案。应用谱强迫方案将湍流条件维持在泰勒微尺度雷诺数为 61 的情况下。模拟包含 2 至 10 vol% 的颗粒，固体与流体的密度比为 1.15 至 1.73。润滑力用于解释接近颗粒之间的亚网格流体动力相互作用。结果显示了颗粒相对湍流谱和颗粒碰撞的影响。模拟的能谱表明，颗粒在颗粒尺寸量级的长度尺度上产生流体运动。这导致在这些长度尺度上能量耗散率大幅增加，并且在更大长度尺度上动能减少。观察到由于不相关的粒子运动引起的碰撞（初级碰撞），并且碰撞频率与惯性粒子碰撞理论一致。除此之外，还会遇到大量的高频碰撞。这些二次碰撞是由于短程流体动力相互作用和短距离湍流速度场的空间相关性引起的粒子相关运动造成的。这一观点得到了相对粒子速度分布、粒子速度相关函数和粒子径向分布函数的支持。
Fully resolved simulations of particles suspended in a sustained turbulent flow field are presented. To solve the Navier–Stokes equations a lattice-Boltzmann scheme was used. A spectral forcing scheme is applied to maintain turbulent conditions at a Taylor microscale Reynolds number of 61. The simulations contained between 2 and 10 vol % particles with a solid to fluid density ratio between 1.15 and 1.73. A lubrication force is used to account for subgrid hydrodynamic interaction between approaching particles. Results are presented on the influence of the particle phase on the turbulence spectrum and on particle collisions. Energy spectra of the simulations show that the particles generate fluid motion at length scales of the order of the particle size. This results in a strong increase in the rate of energy dissipation at these length scales and a decrease of kinetic energy at larger length scales. Collisions due to uncorrelated particle motion are observed (primary collisions), and collision frequencies are in agreement with theory on inertial particle collisions. In addition to this, a large number of collisions at high frequencies is encountered. These secondary collisions are due to the correlated motion of particles resulting from short-range hydrodynamic interactions and spatial correlation of the turbulent velocity field at short distances. This view is supported by the distribution of relative particle velocities, the particle velocity correlation functions and the particle radial distribution function.