2019 Volume 75 Issue 2 Pages I_509-I_518
Self-similar clustering of inertial particles in homogeneous isotropic turbulence has been suggested both by numerically and theoretically. The self-similar clustering may be explained by the co-existing self-similar multi-scale coherent eddies in the turbulence. However, such self-similar relationship between particle clustering and multi-scale eddies has not been directly extracted yet. In this paper, we analyze the data from direct numerical simulation of incompressible homogeneous turbulence, by sampling high vorticity regions in coarse-grained fields and by taking their average using the frame of eigenvectors of the coarse-grained rate-of-strain tensor. The results show that the high vorticity regions make a low particle density region whose size and shape depend on the coarse-grained level and the particle inertia. By tracking the motion of the inertial particles in the averaged velocity field, we find that the particles orbit an elliptical region whose size depends on the coarse-grained level and the particle inertia.
