Influence of particle inertia on scalar mixing

The influence of partial inertia on scalar mixing in homogeneous isotropic turbulent flows was studied using a direct numerical simulation (DNS) method. The results show that, compared with the case without particle, micro-particle increases the high wavenumber values of scalar variance spectrum and most of 25% scalar dissipation; larger particle decreases scalar variance at the initial stage of simulation remarkably, and accelerates the decay rate of scalar dissipation, the scalar variance and dissipation was mostly lower than that of the case without particle 15% and 5% respectively; critical particle, however, has not obvious influence on scalar mixing in our simulation, the deviation of the scalar fluctuation and dissipation rate was less than 5%. Also with the increasing of particle inertia, probability density distributions of scalar dissipation shift toward left, but the characteristics of these PDFs were of few changes.