Direct simulations of sedimentation of flexible cylindrical fiber suspensions in a finite Reynolds number flow are reported. The simulation method is based on a lattice Boltzmann equation and a flexible fiber model. The results show that at a high Reynolds number the fiber settling velocity increases to a maximum, then decreases, and final reaches a constant terminal speed. There is a large overshooting in the velocity curve. The over shooting increases as the Reynolds number increases. Most fibers will turn to horizontal direction during settling due to inertial effect and form clusters, each with different numbers of fibers. The clusters are randomly distributed and dominated. It confirmed that coagulation or flocculation effect drives muiltfibers to have a larger settling velocity than a single fiber
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