Hydrodynamic pair diffusion in isotropic random velocity fields with application to turbulent coagulation
Hydrodynamic pair diffusion in isotropic random velocity fields with application to turbulent coagulation
复制标题
各向同性随机速度场中的流体动力学对扩散及其在湍流凝聚中的应用
DOI：
10.1063/1.869380
复制
发表时间：
1997
影响因子：
4.6
通讯作者：
L. W. Lion
中科院分区：
文献类型：
--
作者：
Brett K. Brunk;D. Koch;L. W. Lion
在随机、各向同性流动中，研究了流体动力学相互作用、粒子间力和布朗扩散的扩散和凝聚。不同的应变和旋转速率时间尺度表征了速度场，并且假设颗粒相对于流的特征长度较小，因此速度场在颗粒附近呈线性。两个粒子相对运动的对概率方程用扩散张量和漂移速度表示。该方法适用于小应变极限，即特征速度梯度与波动速度梯度时间尺度乘积较小的情况。漂移速度的结果是，在非凝固系统的稳态中，当流体动力相互作用包括在内时，粒子对的概率分布是不均匀的，并且粒子对靠近的概率更高。使用对概率守恒方程…
Diffusion and coagulation are investigated in a random, isotropic flow in the presence of hydrodynamic interactions, interparticle forces, and Brownian diffusion. Different strain and rotation rate time scales characterize the velocity field and the particles are assumed small compared with the characteristic length of the flow, so that the velocity field is linear in the vicinity of the particles. The pair probability equation for the relative motion of two particles is written in terms of a diffusion tensor and a drift velocity. This technique is valid in the limit of small strain, i.e., when the product of the characteristic velocity gradient and time scale of the fluctuating velocity gradient is small. A consequence of the drift velocity is that, at steady state in a noncoagulating system, the pair probability distribution is nonuniform when hydrodynamic interactions are included, and there is a higher probability of particle pairs at close proximity. The pair probability conservation equation is used...