Flow past a single stationary sphere, 2. Regime mapping and effect of external disturbances

Abstract

This review presents a systematic analysis of the published literature on flow regime mapping and effects of external disturbances for flow past a single stationary sphere. Various experimental and numerical investigations have been performed over the past years on such flows over a wide range of Re. The first part of this review (Tiwari et al. [1]) explained the methodologies to carry out these investigations and the statistical tools used for analyzing the flow behavior. This part presents the findings on the flow parameters such as pressure and force coefficients, Reynolds stresses, velocity and vorticity. Also, the physical significance of wake structures and their contribution in enhancing/ reducing the turbulence and mixing in the flow has been elaborated. According to the available findings from the published literature a regime map has been presented to categorize the flow into eight different regimes. The effect of disturbances such as the presence of walls, surrounding particles, free surface, stratification and external perturbations on these flow regimes have also been covered in brief. In this review a coherent presentation has been made on transitional journey of flow past an isolated stationary single sphere from creeping flow to highly turbulent regimes. In addition to this, a short section has been included to show the significance of detailed knowledge of a rather fundamental issue of flow past a sphere in designing and optimizing some process equipment such as a packed bed and a fluidized bed reactor.