Gravity-Driven Enhancement of Heavy Particle Clustering in Turbulent Flow
Gravity-Driven Enhancement of Heavy Particle Clustering in Turbulent Flow
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DOI：
10.1103/physrevlett.112.184501
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发表时间：
2014-05-08
影响因子：
8.6
通讯作者：
Ray, Samriddhi Sankar
中科院分区：
文献类型：
--
作者：
Bec, Jeremie;Homann, Holger;Ray, Samriddhi Sankar
在湍流中悬浮的重颗粒比在静止流体中沉降得快。这种效应源于对流体向下流动的区域的优先采样，并在这里量化为湍流水平、粒子惯性和重力与湍流加速度之比的函数。通过分析方法和详细的、最先进的数值模拟，沉降显示出有效的水平二维动力学，增加聚类并降低颗粒之间的相对速度。这两种相互竞争的效应可以增加或减少相同大小的粒子之间的几何碰撞率，对于真实模拟聚结粒子是至关重要的。
Heavy particles suspended in a turbulent flow settle faster than in a still fluid. This effect stems from a preferential sampling of the regions where the fluid flows downward and is quantified here as a function of the level of turbulence, of particle inertia, and of the ratio between gravity and turbulent accelerations. By using analytical methods and detailed, state-of-the-art numerical simulations, settling is shown to induce an effective horizontal two-dimensional dynamics that increases clustering and reduce relative velocities between particles. These two competing effects can either increase or decrease the geometrical collision rates between same-size particles and are crucial for realistic modeling of coalescing particles.