Parallel Simulation of Fluid Slip in a Microchannel

Fluid flow in channels has traditionally been assumed to satisfy a no-slip condition along the channel walls. However, it has recently been found experimentally that the flow in microchannels can slip along hydrophobic (repelling water) walls. The slip can have important physical consequences for such flows. The physical mechanism underlying this phenomena is not well understood. An accurate, physically realistic model that can be simulated rapidly is critical for obtaining a better understanding of these results, and ultimately for modeling and for optimizing the flow in microdevices to achieve desired objectives. This paper investigates the parallel simulation of fluid slip along microchannel walls using the multicomponent lattice Boltzmann method (LBM) with domain decomposition. Because of the high complexity for microscale simulation, even a parallel computation of fluid slip can take days or weeks. Any slowness in the participating nodes in a cluster can drag the entire computation substantially, due to frequent node synchronization involved in each computational phase of the algorithm. We augment the parallel LBM algorithm with filtered dynamic remapping for lattice points. This filtered scheme uses lazy remapping and overredistribution strategies to 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 can greatly speed up fluid slip simulation on a non-dedicated cluster over a long period of execution time.

Abstract Parallel Simulation of Fluid Slip in a Microchannel

Fluid flow in channels has traditionally been assumed to satisfy a no-slip condition along the channel walls. However, it has recently been found experimentally that the flow in microchannels can slip along hydrophobic (repelling water) walls. The slip can have important physical consequences for such flows. The physical mechanism underlying this phenomena is not well understood. An accurate, physically realistic model that can be simulated rapidly is critical for obtaining a better understanding of these results, and ultimately for modeling and for optimizing the flow in microdevices to achieve desired objectives. This paper investigates the parallel simulation of fluid slip along microchannel walls using the multicomponent lattice Boltzmann method (LBM) with domain decomposition. Because of the high complexity for microscale simulation, even a parallel computation of fluid slip can take days or weeks. Any slowness in the participating nodes in a cluster can drag the entire computation substantially, due to frequent node synchronization involved in each computational phase of the algorithm. We augment the parallel LBM algorithm with filtered dynamic remapping for lattice points. This filtered scheme uses lazy remapping and over-redistribution strategies to 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 tech-£ This work was supported by NSF/ITR ACI-0086061 ¡ jzhou, zhuld, petzold, tyang