Pressure center determination for regularly shaped non-spherical particles at intermediate Reynolds number range

Abstract

The present contribution aims to determine the dependence of the location of the non-dimensional center of pressure (λ) with orientation (β) for non-spherical particles of regular shape. Prolate and oblate ellipsoids as well as cylinders of various aspect ratios (AR) at several Reynolds numbers (Rep) have been considered. The required flow coefficients (drag, lift and pitching torque) were determined through DNS and validated with recently published results. The strategy for determining the center of pressure consisted in the evaluation of the pitching torque acting on the non-spherical particles resulting from the fluid-dynamic forces (i.e. drag and lift) and its comparison with the torque directly determined from DNS. The performed analysis did not only allow determining the shape of the curve λ(β), but also revealed that the location of the center of pressure depends additionally on particle aspect ratio and Reynolds number. It is found that for all the particles considered, the position of the center of pressure at a fixed incidence angle displaces upstream of the geometrical center with increasing Reynolds number; additionally, it exhibits a non-monotonic behavior in dependence of the aspect ratio.