We present the formulation of a kinetic mapping scheme between the Direct
Simulation Monte Carlo (DSMC) and the Lattice Boltzmann Method (LBM) which is
at the basis of the hybrid model used to couple the two methods in view of
efficiently and accurately simulate isothermal flows characterized by variable
rarefaction effects. Owing to the kinetic nature of the LBM, the procedure we
propose ensures to accurately couple DSMC and LBM at a larger Kn number than
usually done in traditional hybrid DSMC-Navier-Stokes equation models. We show
the main steps of the mapping algorithm and illustrate details of the
implementation. Good agreement is found between the moments of the single
particle distribution function as obtained from the mapping scheme and from
independent LBM or DSMC simulations at the grid nodes where the coupling is
imposed. We also show results on the application of the hybrid scheme based on
a simpler mapping scheme for plane Poiseuille flow at finite Kn number.
Potential gains in the computational efficiency assured by the application of
the coupling scheme are estimated for the same flow.Comment: Submitted to Journal of Computational Scienc