Coarse-grained simulation of chaotic mixing in laminar flows

A model for chaotic mixing has been formulated and tested. The advection of a passive scalar by laminar flows with high Peclet numbers is modeled by a finite-volume method on a coarse grid. The scales which are smaller than the increment of the grid are modeled by an approximate subgrid model. The artificial diffusivity of the finite-difference method plays a twofold role. It prevents the formation of spurious oscillations of the solution and also models the transport of the variation of the scalar from the large to subgrid modes.