Antipov Anatoly E, Barzykin Alexander V, Berezhkovskii Alexander M, Makhnovskii Yurii A, Zitserman Vladimir Yu, Aldoshin Sergei M
Moscow State University, Faculty of Fundamental Physical and Chemical Engineering, GSP-1, 1-51 Leninskie Gory, Moscow 119991, Russia.
The Royal Bank of Scotland, 250 Bishopsgate, London EC2M 4AA, United Kingdom.
Phys Rev E Stat Nonlin Soft Matter Phys. 2013 Nov;88(5):054101. doi: 10.1103/PhysRevE.88.054101. Epub 2013 Nov 7.
Diffusion in a tube of periodically varying diameter occurs slower than that in a cylindrical tube because diffusing particles get trapped in wells of the periodic entropy potential which is due to variation of the tube cross-section area. To quantify the slowdown one has to establish a relation between the effective diffusion coefficient of the particle and the tube geometry, which is a very complicated problem. Here we show how to overcome the difficulties in the case of a periodically expanded conical tube, where we find an approximate solution for the effective diffusion coefficient as a function of the parameters determining the tube geometry.
在直径周期性变化的管道中,扩散比在圆柱形管道中发生得慢,这是因为扩散粒子被困在由管道横截面积变化所导致的周期性熵势阱中。为了量化这种减速,必须建立粒子的有效扩散系数与管道几何形状之间的关系,这是一个非常复杂的问题。在这里,我们展示了如何在周期性扩张的锥形管道的情况下克服这些困难,在这种情况下,我们找到了有效扩散系数作为确定管道几何形状的参数的函数的近似解。