Predicting Frictionless Flows

Nearly drag-free flow through carbon nanotubes (CNTs) was recently demonstrated.\footnote{ M. Majumder et al. \textit{Nature} \textbf{438}: 44 (2005), J. K. Holt et al. \textit{Science} \textbf{312}: 1034 (2006) \par \par } Flow rates orders of magnitude above that predicted by applying the no-slip boundary condition were measured. We formulate an analytical model which reproduces the high-speed flow observed. As inferred from the experiments, we find extremely large slip lengths. Unlike the no-slip condition which applies equally to all materials, the amount of slip is dependent on material parameters. CNTs can be made with different diameters and lattice structure. We show how CNT properties affect the amount of slip. The properties of the liquid also affect the amount of slip, and we show how the orientation of water molecules affects the amount of slip. We also show how to design CNT flows with the maximum amount of slip.