Dynamics of bacterial flagellum in a channel flow for design of artificial microrobot

摘要

Design of artificial microrobot based on the propulsion behavior of flagellated bacteria has got immense interest in the recent times due its potential in the field of biomedical applications. Such design will depend not only the structural features of the bacterial helical flagellum but also the fluid flow dynamics. Further, the size of the channel and the initial position of the flagellum in the channel under pressure driven fluid flow will also affect the swimming strategy of the flagellum based robot design. With this perspective, numerical study is carried out in this paper by constructing a computational model to investigate the dynamics of helical flagellum of a bacterium under fluid flow in a channel. The problem involves fluid-structure interaction with the structure being highly flexible and the fluid is flowing from inlet to outlet of the channel making the study complex and challenging. Accordingly, an immersed boundary method based numerical model is created in which flagellum is constructed using elastic link network and the flow is modeled using Stokes equations. Numerical simulations are done mainly to see the effect of channel size and the initial location of the flagellum in the channel on the propulsive dynamics of the flagellum. Forward and mean forward swimming speeds of the helical flagellum are computed to present a comparison for each case using the built model.