Numerical investigation of rarefied gaseous flows in an oblique wavy sided walls square cavity

This paper intends to analyze computationally the rarefied gaseous flow and performance of heat transfer for a steady-state laminar 2D free convection within tilted enclosures where the sided walls are of wavy shape. Lowpressure or rarefied flows are flows with Knudsen number greater than zero. These kinds of flows are of incredible significance in different applications. Boussinesq estimation is adopted to represent the buoyancy effects. Grid independence tests are carried out to ensure accuracy. Moreover, the current code is verified with numerical and experimental results existing in the literature. Flow and thermal fields for simulated cases are presented. The outcome of this research indicates that there is a direct relationship between the average Nusselt number and the Rayleigh number, and a converse relationship between the average Nusselt number and Knudsen number. Additionally, the numerical simulations reveal that increasing the amplitude of the two-sided wavy walls of the enclosure slightly mends the transfer of heat. Besides, it is determined that the tilt angle slightly affects the heat transfer performance of such flows; and it is evident from the simulations that horizontal or nearly horizontal orientations of such cavities give the maximum transfer of heat. Finally, a correlation representing the relationship of the average Nusselt number in terms of all the examined parameters is introduced.