DNS Study Of Interactions Between Clouds OfParticle And Isotropic Homogeneous TurbulentFlow

Turbulence modulations of isotropic homogeneous turbulence by solid particles were investigated microscopically by means of direct numerical simulation (DNS) that take volume of particle into account. Our primary object is to investigate how turbulence structure is modified by particles, this may play an essential role in turbulence modulation, from microscopic view. Particle diameters were set considerably larger than Kolmogorov micro scale. To verify the fundamental processes that occur locally, particle locations and velocities were defined arbitrary. The modified flow micro-structure by the existence and motion of particles showed distinctions between two cases of particle Reynolds number. In Re, = 60 case, background vortex tubes were seemed to retain their dimensions by evading particles. In Re, = 300 case, on the other hand, higher inertia of particle enhances fragmentation of vortices, stretching and wake shedding. Higher dissipative region were formed around and tail of particles. Production of smaller eddies which have disproportioned high energy and localized high dissipative regions may contribute to the turbulence augmentations.