Hydrodynamic interaction of elastic membranes in a stenosed microchannel

In this research, the dynamics of elastic membrane(s) having different elastic modulus in a microchannel with stenosis is simulated numerically using a combined lattice Boltzmann-immersed boundary (LB-IB) method. The membranes are considered as elastic boundaries immersed in the fluid flow. In IBM, the immersed boundary is represented in Lagrangian coordinates, while the fluid flow field is discretized by a uniform and fixed Eulerian mesh. Interaction between the fluid and the membranes is modeled using an appropriate Dirac delta function. The results were found to be in good agreement with available numerical data. First, the motion and deformation of a single elastic membrane in a microchannel with stenosis is studied and the influences of shear elastic modulus and bending resistance on the membrane deformation are evaluated. It was found that by increasing the elastic modulus, the deformation and velocity of the membrane decrease and a greater drag force is imposed on the membrane with greater hardness. Finally, the effects of simultaneous presence of three membranes on the flow velocity profile and pressure field are investigated. The results showed that the more rigid the membranes become, the flatter velocity profile and the higher pressure occur in the stenosis section. This increased pressure is thought to be the reason of many serious diseases including cardiovascular diseases if circular membranes are considered as red blood cell.