Parallel Simulation of Fluid Slip in a Microchannel

Fluid flow in channels has traditionally been assumed to satisfy ano-slip condition along the channel walls. However, it has recentlybeen found experimentally that the flow in microchannels can slipalong hydrophobic (repelling water) walls. The slip can haveimportant physical consequences for such flows. The physicalmechanism underlying this phenomena is not well understood. Anaccurate, physically realistic model that can be simulated rapidly iscritical for obtaining a better understanding of these results, andultimately for modeling and for optimizing the flow in microdevices toachieve desired objectives. This paper investigates the parallel simulation of fluid slip alongmicrochannel walls using the multicomponent lattice Boltzmann method(LBM) with domain decomposition. Because of the high complexity formicroscale simulation, even a parallel computation of fluid slip cantake days or weeks. Any slowness in the participating nodes in a clustercan drag the entire computation substantially, due to frequent nodesynchronization involved in each computational phase of thealgorithm. We augment the parallel LBM algorithm with filtered dynamicremapping for lattice points. This filtered scheme useslazy remapping and over-redistribution strategiesto balance the computational speed of participating nodes and to minimize the performance impact of slow nodes on synchronized phases.Our experimental results indicate that the proposed technique cangreatly speed up fluid slip simulation on a non-dedicated cluster overa long period of execution time.