Influence of gravity on collisions of monodispersed droplets in homogeneous isotropic turbulence
Influence of gravity on collisions of monodispersed droplets in homogeneous isotropic turbulence
复制标题
重力对均匀各向同性湍流中单分散液滴碰撞的影响
DOI：
10.1063/1.3276906
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发表时间：
2009
影响因子：
4.6
通讯作者：
S. Komori
中科院分区：
文献类型：
--
作者：
R. Onishi;Keiko Takahashi;S. Komori
本文通过直接数值模拟（DNS）研究了重力对均匀各向同性湍流中单分散液滴碰撞的影响。 DNS 结果表明，在某些斯托克斯和雷诺条件下，在存在重力的情况下，碰撞频率会显着降低。这些下降主要归因于液滴相对速度的下降，因为径向分布函数（通常称为优先浓度）的变化很小。进一步分析结果表明，重力引起的液滴沉降缩短了液滴与流体的相互作用时间，从而削弱了液滴之间的相对运动。这些观察结果得出了一个分析模型，可用于估计重力下沉积颗粒的速度波动。利用这个模型，我们构建了一个进一步的分析模型来估计重力对碰撞的影响。给定流量和颗粒参数，该模型计算速率...
This paper studies the gravity influence on collisions of monodispersed droplets in homogeneous isotropic turbulence by means of direct numerical simulations (DNSs). The DNS results show that, in certain Stokes and Reynolds regimes, collision frequencies are significantly reduced in the presence of gravity. Those decreases are mainly attributable to the decrease in the droplet relative velocity, since the change in radial distribution function—often referred to preferential concentration—is small. Further analysis of the results reveals that droplet sedimentation due to gravity shortens the droplet-fluid interaction time, consequently weakening the relative motions between droplets. These observations lead to an analytical model that can be used to estimate the velocity fluctuations of sedimenting particles under gravity. Utilizing this model, we constructed a further analytical model for estimating the gravitational influence on collisions. Given flow and particle parameters, the model calculates the rat...