Effect of membrane viscosity in dynamics of red blood cell in pulsatile flows*

We investigate the impact of membrane viscosity in the dynamics of Red Blood Cell (RBCs) in pulsatile flows using numerical simulations. Our computational approach employs a hybrid continuum-particle coupling. The Red Blood Cell model includes the cell membrane and cytosol fluid, which are modeled using the Dissipative Particle Dynamics (DPD) method. The blood plasma is modeled as an incompressible fluid via the Immersed Boundary Method (IBM). The hybrid continuum-particle coupling is carried out on the membrane surface by the continuity of the loading vector. Our numerical method provides an accurate description of RBC dynamics while the extracellular flow patterns around the RBCs are also captured in detail. Our coupling methodology is validated with available experimental and computational data in the literature and shows good agreement. Our simulation results show that a host of RBC morphological dynamics emerges depending on the value of membrane viscosity. Our results show that the RBC shape is strongly dependent on the membrane viscosity. Our results suggest that the controlling of membrane viscosity can be used to induce specific morphological shapes of RBCs and the surrounding fluid patterns in bio-engineering applications.