Centripetal focusing of gyrotactic phytoplankton in solid-body rotation

Autor:	Cencini, M., Franchino, M., Santamaria, F., Boffetta, G.
Rok vydání:	2015
Předmět:	Physics - Fluid Dynamics Physics - Biological Physics Quantitative Biology - Quantitative Methods
Druh dokumentu:	Working Paper
Popis:	A suspension of gyrotactic microalgae Chlamydomonas augustae swimming in a cylindrical water vessel in solid-body rotation is studied. Our experiments show that swimming algae form an aggregate around the axis of rotation, whose intensity increases with the rotation speed. We explain this phenomenon by the centripetal orientation of the swimming direction towards the axis of rotation. This centripetal focusing is contrasted by diffusive fluxes due to stochastic reorientation of the cells. The competition of the two effects lead to a stationary distribution, which we analytically derive from a refined mathematical model of gyrotactic swimmers. The temporal evolution of the cell distribution, obtained via numerical simulations of the stochastic model, is in quantitative agreement with the experimental measurements in the range of parameters explored. Comment: 16 pages, 5 figures
Databáze:	arXiv
Externí odkaz:	http://arxiv.org/abs/1511.01255 Zobrazit plný text záznamu View this record from Arxiv