In a recent computational investigation, Yazdani et al. [Phys. Rev. E 83, 046305 (2011)] reported an exponential (logarithmic) dependence of the tank-treading frequency $F_{tt}$ with the viscosity ratio $\lambda$ at low (moderate) viscosity ratios for erythrocytes in shear flows. We argue that the authors misinterpreted the inverse linear dependence on $\lambda$ of the tank-treading frequency $F_{tt}$, as found by Wodson and Dimitrakopoulos [Biophys. J. 99, 2906 (2010)], owing to the fact that Yazdani et al. plotted their frequency-versus-$\lambda$ results in a log-log plot.

• Received 12 June 2011

DOI:https://doi.org/10.1103/PhysRevE.84.058301