Red blood cell motion: an intermittent behavior with one tumbling and one tank-treading.

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Red blood cell motion can have an intermittent behavior in simple shear flow due to the energy barrier associated with its membrane structure such as the one has a nonuniform spring network. During the tank-treading motion, the spring network rotates on the rbc boundary and then has the variation of the energy associated with the spring network at its position. The maximal value of the membrane energy is the energy barrier for the tank-treading motion. In shear flow, the fluid flow pushes the RBC membrane to tank-tread; but it may not be strong enough so that the membrane can overcome the energy barrier. Thus the RBC rotates instead of having tank-treading. But with previously stored energy and the next push from the fluid flow, the membrane can have a complete tank-treading motion. Therefore there is an intermittent behavior with one tumbling and one tank-treading (more detail can be found in Biomechanics and Modeling in Mechanobiology 14 (2015), 865-876).