Wake structures of a particle in straight and curved flows

Abstract

To investigate the effect of non-axisymmetric shear on the wake structure of a particle, the flows around a single spherical particle in the following two kinds of shear flows are simulated: parallel (streamwise) shear and curved (crossstreamwise) shear flows. The ranges of the particle Reynolds number and the shear Reynolds number are determined by assuming that the particle size is comparable to the Kolmogorov length scale in a turbulent flow. The effect of the parallel shear on the perturbation velocity is small. For the curved shear, the wake region is deflected in space. However, the width of the wake is almost unchanged near the particle. For the fixed and translating particle cases, even if the streamlines of the undisturbed flow relative to the particle translation are similar to each other, the difference of the ambient pressure gradient makes the difference of the velocity distributions.