Molecular dynamics simulation of Couette and Poiseuille Water-Copper nanofluid flows in rough and smooth nanochannels with different roughness configurations

In this study, molecular dynamics simulation of Couette and Poiseuille Water-Copper nanofluid flows in rough and smooth nanochannels was performed. The Lennard-Jones equation is considered as Water-Water intermolecular interaction, while Hamaker's equation is considered to be the interaction between Water-Copper and Copper-Copper particles. PPPM algorithm is used to calculate the electric potential. It is concluded that increasing the channel height reduces the effect of the surface on the fluid and reduces the flow rate of the nanofluid. Also, the slip velocities on the bottom and top walls remain almost the same. Furthermore, nanoparticles have caused fluctuations in the middle area, which are due to the effects of the surface of the nanoparticles relative to the base fluid of the Water. As expected, the presence of nanoparticles in the middle area and the interaction between the surface and the fluid in this area has caused abnormal fluctuations.