Effect of dissipative coupling parameter in a computational model on the inclination angle of red blood cells in a shear flow

Red blood cells immersed in a shear flow exhibit several stable states including tumbling, swinging and tank treading. With higher values of shear rate above a certain threshold, the cells undergo purely tank treading motion characterised by the motion of the cell membrane around the inner fluid of the cell. In this state of motion, the cells appear to be slender bodies, similar to ellipsoids. Their orientation can be quantified by an angle of inclination. of the major axis with respect to the flow direction. Experimental studies measured this angle and computational models may be validated against this data. We consider a computational model of red blood cell immersed in a flow composed of two parts: fluid is discretised by a fixed grid with underlying evolution equations known as the lattice-Boltzmann method, while the cell membrane is approximated by a triangular spring network. Both meshes are coupled via dissipative coupling mimicking the natural no-slip boundary conditions on the interface between the fluid and the structure. The strength of this coupling is determined by the friction coefficient.. In this work we focus on validating the correct values of friction coefficient against the biological experiments involving the measurements of inclination angle of red blood cells immersed in a shear flow. We validate the previously derived relation for computation of.. Furthermore we provide analysis of the inclination angles for simulated cells for different values of shear rate.