Statistical Law of Turbulence in Granular Gas

Abstract

A novel description of granular gases from the viewpoint of “fluid turbulence” is presented. In the large-scale simulation by event-driven molecular dynamics simulations, we obtained clear evidence for the energy and enstrophy (square of vorticity) cascade, in which we found −5/3 (3D) and −3 (2D) exponents predicted by the Kolmogorov and Kraichnan-Leith-Bachelor energy spectrum, respectively. The growth of the Reynolds number based on the Taylor microscale confirmed that the cascade regimes were that of fully developed turbulence. During the evolving process of the regime in fully developed turbulent inhomogeneous state, we discovered a new regime arose from the collision between “clusters”, in which the previous theoretical predictions of the energy decay in this regime collapse.