Abstract
This paper presents a fluid-particle interaction algorithm using the distributed Lagrange multiplier based fictitious domain method. The application of this method to the numerical investigation of motion and aggregation of red blood cells in two-dimensional microvessels is discussed. The cells are modelled as rigid biconcave-shaped neutrally buoyant particles. The aggregating force between two cells is derived from a Morse type potential function. The cell-cell interaction is coupled with the fluid-cell interaction through a time splitting scheme. Simulation results of multiple red blood cells in Poiseuille flow are presented. Because of its modular nature, this algorithm is applicable to a large class of problems involving the processes of particle aggregation and fluid-particle interaction.