Direct simulation of roughness effects on rarefied and compressible flow at slip flow regime

Numerical Simulation of Roughness in Microchannels by Using the Second-Order Slip Boundary Condition

“…Different peak densities for both compressible and incompressible models were used. The Poiseuille number was obtained by applying the second-order slip boundary condition and was compared to similar results of Shams et al [29]. It was found that the greater the roughness elements per length, the greater the average f Re was.…”

“…Ji et al [5] applied a second-order boundary condition to rectangular elements of roughness and studied the Nusselt number. A study by Shams et al [29] also showed the effects of roughness on Poiseuille and Nusselt numbers using first-order slip and temperature jump boundary conditions. The focus of this study was on the slip flow regime, especially the area close to the transitional regime where the use of the second-order slip boundary conditions becomes necessary.…”

Slip Flow of Nanofluids between Parallel Plates Heated with a Constant Heat Flux

“…The results showed that as the permeability is decreased, velocity distribution tends to be more uniform and therefore Nusselt number increases. (Shams et al, 2009) studied slip flow in rhombus microchannels and concluded that aspect ratio and Knudsen number have important effect on Poiseuille number and Nusselt number. The results also showed that Reynolds number has also considerable influence on Nu number at low Re numbers.…”

“…They also concluded that gaseous rarefaction and compressibility increase with the increase of the wall heat flux. (Shams et al, 2009) performed a numerical simulation for incompressible and compressible fluid flows through microchannels in slip flow regime and found that the effect of compressibility ise more noticeable when relative roughness increases. (Zhang et al, 2010) studied the effect of viscous heating on heat transfer performance in microchannel slip flow region and found that the viscous heating causes severely distortions on the temperature profile.…”

Slip at Fluid-Solid Interface

“…Other simulation and numerical methods have also been employed to investigate slip and slip-related issues. 13,41,42,61,63,73,85,92,96,98,110,146,[183][184][185][186][187][188][189][190][191] Some of these methods have been used to overcome stated limitations in molecular dynamics (MD) simulations of not being able to reach low shear rates and large system sizes 98 because MD simulations are usually limited in size to systems on molecular scale (or a few multiples larger) due to practical restrictions on the computational resources. It is noteworthy that nonslip condition may be relaxed in some numerical simulations to avoid singularities.…”