A new method for direct simulations of flexible filament suspensions in non‐zero Reynolds number flows

A new method for direct simulations of flexible filament suspensions in a non‐zero Reynolds number flow is developed. For fluid domain, simulations are based on a lattice Boltzmann equation. For solid domain, a slender solid body is discretized into a chain of consecutive spherical segments contacting each other. A constraint force algorithm is proposed to warrant constant bonding distance between two neighbouring segments and non‐slip velocity conditions at the contacting points so that the flexible filament moves and rotates as a whole body. The fibre could be bent and twisted in the model. Non‐linear inertial interactions between fluid and flexible filament can be naturally studied by using this model embedded in the lattice Boltzmann scheme. The present flexible fibre method is tested by using a rigid particle method when the fibre stiffness is very large and by comparing the present results with theoretical and experimental results. It is demonstrated that the present results have a reasonable accuracy and that the computational results are consistent with the existed experimental results at non‐zero Reynolds number flows. Copyright © 2006 John Wiley & Sons, Ltd.