Novel flow behaviors induced by a solid particle in nanochannels: Poiseuille and Couette

We conducted a molecular dynamics (MD) simulation to address the novel flow behaviors induced by a solid particle in nanochannels. Two basic flows, i.e., Poiseuille and Couette, are involved in this study. For Poiseuille flow, the distribution of number density exhibits fluctuations in the center of channel and near the walls, which are caused by the strong interactions from the atoms of particle and walls. For stronger external driving forces, the fluid atoms move toward the center of channel and some cavities appear in the fluidic zone. Greater external driving forces and bigger particles make the fluid moving quickly in nanochannels. For Couette flow, the particle rotates under the velocity difference among particle atoms in the shear flows. The fluid atoms near the walls become infrequent and move to the center of channel. The velocities of the centrally-located fluid atoms decrease owing to the particle, resulting in an untypical non-linear Couette flow. In summary, the solid particle brings new fluid-solid interface and interactions, which induce several novel behaviors in nanochannel flows.