Viscous flow around spherical particles in different arrangements

Sofia University, Department of Mathematics and Informatics, James Boucher blvd. No. 5, 1014 Sofia, Bulgaria

^* Corresponding author: tkotsev@fmi.uni-sofia.bg

Abstract

Viscous flow past two or more spherical particles in direction parallel or perpendicular to the line connecting the body centers is studied numerically at Reynolds number up to 200. The FEM is used to simulate the flow structure for different arrangements and diameters of the spheres. The drag and lift coefficients are calculated as functions of the flow velocity and the distance between the spheres. The results show the downstream spheres face a reduced drag compared to a single sphere and that the upstream one changes its drag coefficient according to the distance between the bodies. In the case of side by side arranged spheres, an effect of repulsion exists up to a certain separation distance and after that a weak pulling effect appears. A configuration of three (or more) spherical particles arranged in „V“ formation was examined where one body is set to be a leading and the others are located symmetrically up and down behind it. The flow characteristics are studied when the angle behind the leading sphere vary from 40° to 180°. This configuration supposes stronger interaction between the bodies due to the influence of the wakes behind the first sphere to the downstream ones and to the lift forces appeared.