Coarse-grained area-difference-elasticity membrane model coupled with IB-LB method for simulation of red blood cell morphology

The morphologies of red blood cells (RBCs) in fluid environment have attracted many research interests. We propose a coarse-grained membrane model based on the area-difference-elasticity (ADE) model, and integrate the immersed boundary (IB) method and lattice Boltzmann (LB) method for the simulations of vesicles and RBCs. The membrane's energy is composed of bending energy, ADE energy, area energy, volume energy and the elastic energy of the membrane skeleton. The fluid environment is solved by the LB method, and the membrane and fluid models are coupled by the IB method. With only bending energy and area energy, the cells show the prolate-oblate-stomatocyte transition with decreasing volume. If all energy components are included, the stomatocyte-discocyte-acanthocyte transition of the cell morphology is recovered with increasing area difference between the two leaflets of the membrane. Therefore, the proposed numerical model is capable to simulate the morphology of the RBC in various scenarios. This model can be further employed to study the deformation of cells in blood flows.