Analytical solution of plane Couette flow in the transition regime and comparison with Direct Simulation Monte Carlo data

• Quantitative solution for the steady-state Couette flow problem in the transition flow regime is provided.
• Various higher order continuum model results compare well against DSMC data, especially at high Knudsen numbers.
• A new slip relationship has been formulated and tested.

This paper provides analytical solution for the steady-state Couette flow problem in the transition flow regime, while capturing the non-linear Knudsen layer near the walls. Slope at the center obtained from Direct Simulation Monte Carlo (DSMC) data and inherent symmetry in the problem have been utilized for obtaining the solution. A detailed study of the solutions obtained from the linearized super-Burnett, augmented Burnett and R13 equations is presented. The analytical results are compared against DSMC data; good agreement between them is shown till Kn = 10. These are among the first set of analytical solutions in the transition regime. The results indicate that the solution tends to become linear as the Knudsen number increases. The results have allowed formulation of a slip relationship, which can potentially yield more accurate slip velocity than Maxwell’s slip model in the transition regime. Our analysis suggests that the Knudsen number envelope over which the R13 and higher-order continuum equations can be employed is substantially extendable.