Lattice Boltzmann Simulations On The Tumbling To Tank-Treading Transition: Effects Of Membrane Viscosity

The tumbling to tank-treading (TB-TT) transition for red blood cells (RBCs) has been widely investigated, with a main focus on the effects of the viscosity ratio gamma (i.e., the ratio between the viscosities of the fluids inside and outside the membrane) and the shear rate (gamma) over dot applied to the RBC. However, the membrane viscosity mu(m) plays a major role in a realistic description of RBC dynamics, and only a few works have systematically focused on its effects on the TB-IT transition. In this work, we provide a parametric investigation on the effect of membrane Viscosity mu(m) On the TB-TT transition for a single RBC. It is found that, at fixed viscosity ratios lambda, larger values of mu(m) lead to an increased range of values of capillary n u m her at which the TB-TT transition occurs; moreover, we round that increasing lambda or increasing mu(m) results in a qualitatively but not quantitatively similar behaviour. All results are obtained by means of mesoscale numerical simulations based on the lattice Boltzmann models.This article is part of the theme issue 'Progress in mesoscale methods for fluid dynamics simulation'. (C) 2021 The Author(s) Published by the Royal Society. All rights reserved.