Numerical simulations supported by previously published experimental data are used to compare the impact of the internal fluid viscosity and the membrane viscosity on a tank-treading red blood cell. The method used is based on a continuum framework both for the fluid and the membrane, their interaction being ensured thanks to the immersed boundary method. The finite-strain model implemented to account for membrane viscosity assumes a free energy form that leads to an additive decomposition of the equilibrium and nonequilibrium stresses. It also assumes that the stress tensor can be separated into a deviatoric part and a hydrostatic part, which are independent. Only the deviatoric part is accounted for in this study. Both the viscosities of the cytoplasm and of the membrane yield a decrease of the tank-treading frequency, with only moderate changes in the deformation of the red blood cell. However, it is shown that the values of tank-treading frequency from the literature cannot be explained by the internal fluid viscosity only. On the contrary, adding the membrane dissipation produces a good agreement with experimental results when using acceptable values of the internal fluid and membrane viscosities. In addition, this study proposes a direct inference of the value of the membrane viscosity as a function of the shear rate from the comparison between simulations and experiments and confirms experimental results that highlighted the shear-thinning behavior of the red blood cell membrane.

中文翻译：

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膜粘度对红血球横行行为的影响

先前发表的实验数据所支持的数值模拟用于比较内部液体粘度和膜粘度对行进坦克的红细胞的影响。所使用的方法基于流体和膜的连续框架，通过浸没边界法确保了它们之间的相互作用。用来解释膜粘度的有限应变模型假定一种自由能形式，该自由能形式导致平衡和非平衡应力的累加分解。还假设应力张量可以分为独立的偏斜部分和静压部分。在这项研究中仅占偏斜部分。细胞质和膜的粘度都会降低储罐踩踏频率，红细胞的变形只有适度的变化。然而，从文献中可以看出，储油箱踩踏频率的值不能仅由内部流体粘度来解释。相反，当使用内部流体和膜的粘度的可接受值时，增加膜的耗散与实验结果可以很好地吻合。此外，本研究通过模拟和实验之间的比较，直接推断出膜粘度值与剪切速率之间的函数关系，并证实了强调红细胞膜剪切稀化行为的实验结果。从文献中可以看出，油底壳踩踏频率的值不能仅由内部流体粘度来解释。相反，当使用内部流体和膜的粘度的可接受值时，增加膜的耗散与实验结果可以很好地吻合。此外，本研究通过模拟和实验之间的比较，直接推断出膜粘度值与剪切速率之间的函数关系，并证实了强调红细胞膜剪切稀化行为的实验结果。从文献中可以看出，油底壳踩踏频率的值不能仅由内部流体粘度来解释。相反，当使用内部流体和膜的粘度的可接受值时，增加膜的耗散与实验结果可以很好地吻合。此外，本研究通过模拟和实验之间的比较，直接推断出膜粘度值与剪切速率之间的函数关系，并证实了强调红细胞膜剪切稀化行为的实验结果。