Influence of dispersed particles on the flow structure in the two-phase wake behind a cylinder at a moderate Reynolds number

The effect of solid particles on the structure of the Karman vortex street in the wake of a circular cylinder is investigated numerically. Two-dimensional unsteady flow of compressible gas is described by the complete Navier–Stokes equations with the additional source terms modelling the effect of the particle phase. The dispersed phase is treated as a discrete media, and its motion is described by the kinetic equation. The inter-particle collisions are negligible under the flow conditions considered in the study. In the numerical algorithm, the dispersed phase is represented by a set of simulated particles. The DSMC method is used with assigning different weights to simulated particles depending on their locations in the calculational domain. The Navier–Stokes equations are solved numerically with the use of a finite-difference scheme splitted by physical processes. For visualization of the unsteady carrier gas flow, the massless particle-markers are used. Flow structures of both phases as well as the drag coefficient and the lift force coefficient of a cylinder are studied depending on the free stream particle concentration. It is found that the intensity of vortices in the wake tends to diminish with the particle concentration, the drag coefficient increases and the amplitude of the lift coefficient decreases.