Orientational behaviors of a carbon nanotube in shear flow

Orientation of a carbon nanotube in fluid under linear shear flow is investigated by molecular dynamics simulations. Argon, described by Lennard-Jones potential, is selected as the surrounding fluid. The nanotube prefers to orient itself around the flow direction with a small angle. Three forms of time-varying orientational behaviors are observed: (i) "Perfect orientation" (the nanotube oscillates around a particular direction); (ii) "Interrupted orientation" (the oscillation is interrupted by a 360° rotation now and then); (iii) "Failed orientation" (the 360° rotations dominate). The shear rate, density and temperature of fluid, length and diameter of nanotube determine the orientational behaviors.