Description of Research Area

Hydrodynamic Effects in Collective Motion of Self-Driven Elements at Low Reynolds Number

Research Subject

Collective motion of self-driven elements in fluids is recently attracting attention as a model of swimming microorganisms. In this project, we focus on two systems which are (1) cilia and (2) self-driven colloidal particles, and investigate the potential of the long-range hydrodynamic interaction to generate collective motion. (1) Cilia are filamentous organelles that are used by single-cell organisms (such as Paramecium) to swim, and exhibit collective travelling waves called metachronal waves. Using a mathematical model that incorporates cilia's shape, elasticity and periodic modulation of the driving force, we study the condition for the metachronal waves to emerge and draw their dynamic phase diagram. (2) An example of self-driven colloidal particles are Janus particles that use catalytic reactions to create chemical gradients and move. Our goal here is to establish a multiscale simulation scheme that extends a hydrodynamic simulation method for conventional colloidal particles, and to clarify the hydrodynamic effects in the collective motion of Janus particles.