Drag on a nanotube in uniform liquid argon flow
Abstract
In this work, nonequilibrium molecular dynamics (MD) simulations were performed to investigate uniform liquid argon flow past a carbon nanotube. In the simulation, nanotubes were modeled as rigid cylinders of carbon atoms. Both argonargon and argoncarbon interactions were calculated based on LennardJones potential. Simulated drag coefficients were compared with (i) published empirical equation which was based on experiments conducted with macroscale cylinders and (ii) finite element (FE) analyses based on NavierStokes equation for flow past a circular cylinder using the same dimensionless parameters used in MD simulations. Results show that classical continuum mechanics cannot be used to calculate drag on a nanotube. In slow flows, the drag coefficients on a singlewalled nanotube calculated from MD simulations were larger than those from the empirical equation or FE analysis. The difference increased as the flow velocity decreased. For higher velocity flows, slippage on the surface of the nanotube was identified which resulted in lower drag coefficient from MD simulation. This explains why the drag coefficient from MD dropped faster than those from the empirical equation or FE simulation as the flow velocity increased. It was also found that the drag forces are almost equal for single and doublewalled nanotubes with the same outer diameter, implying that inner tubes do not interact with fluid molecules.
 Publication:

Journal of Chemical Physics
 Pub Date:
 November 2006
 DOI:
 10.1063/1.2363981
 Bibcode:
 2006JChPh.125q4706T
 Keywords:

 47.27.i;
 47.10.ad;
 47.11.Fg;
 Turbulent flows;
 NavierStokes equations;
 Finite element methods