Modeling of rarefied gas flows in streamwise periodic channels: Application of coupled constitutive relations and the method of fundamental solutions

Abstract

Periodic structures are ubiquitous in nature and engineering, offering unique properties that inspire a range of applications. This paper explores the mathematical modeling of periodic structures in rarefied gas flows using the coupled constitutive relations (CCR) model. The method of fundamental solutions (MFS), known for its meshfree nature and computational efficiency, is utilized as a numerical tool. The streamwise periodic boundary conditions are incorporated into the MFS for modeling two-dimensional flow in periodically patterned channels. We validate the developed CCR-MFS framework with analytical solutions for force-driven Poiseuille and Couette flow. The error analysis is also performed to determine the optimal singularity location. Furthermore, we simulate the flow in channels with periodic patterns by varying the accommodation coefficient. This allows us to analyze the effects of patterning and accommodation coefficients in the Maxwell model of boundary conditions. Effects of patterning on mass flux, energy flux, and average friction coefficients are also presented for the force-driven flow in patterned channels. Our simulations demonstrate the potential of the mathematical and computational techniques to enhance the performance and functionality of a range of technological applications.