On the twoway interaction between homogeneous turbulence and dispersed solid particles
Abstract
The twoway interaction between decaying isotropic turbulence and dispersed solid particles is studied numerically using the method of direct numerical simulation (DNS). Here we discuss the effects of the twoway interaction on particle dispersion. The results indicate that in zero gravity, the twoway coupling enhances the alignment of the surrounding fluid velocity with the direction of the solid particle trajectory. Consequently, the meansquare relative velocity is reduced as compared to its value in the oneway coupling regime. This alignment increases the Lagrangian velocity autocorrelation coefficient of the particle, the fluid point, and the surrounding fluid. The meansquare displacement of the solid particles increases as a result. However, the fluid point meansquare displacement decreases because the larger the inertia of the solid particles the faster is the decay of turbulence energy. In gravity environment, as the solid particles descend through the fluid, they continuously convert their potential energy to kinetic energy, thus augmenting the component of turbulence energy in the gravity direction. The result is an increase the meansquare displacement of the solid particles and fluid points in that direction. However, their dispersion in the lateral directions is reduced due to the crossing trajectories effect.
 Publication:

Joint Propulsion Conference and Exhibit
 Pub Date:
 June 1993
 Bibcode:
 1993jpmc.confR....E
 Keywords:

 Computerized Simulation;
 Dispersions;
 Isotropic Turbulence;
 Suspending (Mixing);
 Weightlessness;
 Autocorrelation;
 Gravitational Effects;
 Fluid Mechanics and Heat Transfer