Monte carlo simulation of nearly kinematic shock fronts in rarefied gases

The effect of inter particle collisions on a “kinematic" shock wave produced by a velocity gradient in a cold atomic gas is studied, to the end of establishing a connection between such kinematic shocks and the “traditional" fluid dynamic shock front. In order to include the collisional effects we use both a DSMC (Direct Simulation Monte Carlo) model and a Monte Carlo solution of the Bhatnagar-Gross-Krook equation (BGK/MC). The substantial agreement of DSMC and BGK/MC results for a suffciently high value of the collision frequency proves that the kinematic and thermodynamic descriptions of the shock front can be smoothly joined by scaling this parameter.