Two-dimensional Stokes flows in porous medium composed of a large number of circular inclusions

摘要

A new approximate approach to solve the two-dimensional boundary-value problems for the Stokes flows in a porous medium composed of a set of circular inclusions is proposed. The idea of the approach, based on the boundary element method (BEM), lies in Fourier series representations of unknown functions on the surfaces of inclusions. It is shown that for small volume concentrations of inclusions, a good accuracy is achieved by taking into account only the first three terms in the Fourier decomposition. Simultaneously, the total number of unknowns, which is equal to the product of the number of inclusions and that of unknowns on every inclusion, is reduced dramatically in comparison with the traditional BEM. The approach is tested by investigating the flow around a circular cylinder in a rectangular periodic cell, the flow in a porous medium with a large number of uniformly or randomly located inclusions. To demonstrate the capacity of the approach, we have calculated the Stokes flows in the porous medium which is modelled by locating 5000 inclusions of two different radii. It is shown that the method can also be used to estimate the properties of the fluid flows in highly porous media formed by non-circular inclusions.