Reference frame influence on transport phenomena in gases. A direct simulations approach

In this paper, the effects of the observation frame on momentum transport and energy transfer in gases are considered. A numerical method of direct simulation is adopted for evaluating the shear stress distribution and the heat flux in the fluid-dynamic field between two rotating walls in a range of Knudsen numbers from free molecular flow to compressible continuum. The numerical solutions are compared with the analytical results where existing. It is shown that the effects of the reference frame increase either with the gas rarefaction or with the angular speed of the frame. With respect to the theoretical debate on the material frame indifference of the transport characteristics in a gaseous continuum, the simulations confirm that the frame dependence vanishes (below the numerical error) as the Knudsen number tends to zero.