高レイノルズ数の乱流中における慣性粒子群の空間分布の流体加速度場による記述

抄録

We propose that the Stokes-number dependence of inertial-particle clustering in turbulence is explained in terms of the structures extracted from the coarse-grained fluid acceleration. To verify this proposal, we conduct direct numerical simulations of small heavy particles subjected to the linear Stokes drag in homogeneous isotropic turbulence. We investigate the surfaces, in three-dimensional space, satisfying the condition for the fluid acceleration which was introduced by Goto and Vassilicos [“Sweep-stick mechanism of heavy particle clustering in fluid turbulence”, Physical Review Letters, Vol. 100 (2008), 054503] and we apply the condition to the coarse-grained fluid acceleration. Our DNS results show that the surfaces thus extracted from the fluid acceleration coarse-grained at different lengths well correlate with the clusters of particles at different Stokes numbers.