Modelling of the Dynamics of an immersed body in a microchannel with stenosis using the immersed boundary method

In the present study, the combination of lattice Boltzmann and immersed boundary methods is used to simulate the motion and deformation of a flexible body. Deformation of the body is studied in microchannel with stenosis and the effect of the flexibility changes on its deformation is investigated. The obtained results in the present manuscript show that by increasing the elasticity modulus, the deformation of the body and its speed decrease. In this case, the flow pressure around the body increase. When the body is initially located outside the microchannel center, tank-treading motion occurs due to the difference in velocity of the shear layers. In addition, with a decrease in the size of microchannel stenosis, the body is less deformed and goes faster and reaches to the end of the microchannel in less time. The faster or slower movement of the biological membranes than the normal state causes the proper exchange of materials between the membrane wall and the surrounding flow and that disturbs its most important duty i.e. the exchange of materials with tissues. The analysis in this study shows that the results of the simulation are in good agreement with the available results and demonstrates the efficiency of the combination of lattice Boltzmann and immersed boundary methods to simulate the dynamic behavior of biological membranes, red blood cells and deformable particles inside the flow.