Open Access

Xue Ao

• Under the current interests of artificial active particles diffusing in the microscopic geometries, we numerically study the transport and diffusion of Janus micro-swimmers along a narrow periodically corrugated channel. With the motivation of the recent experimental development of the active particles with or without chirality, we introduce the Langevin approach to describe 2D model of the bulk diffusion of active particles proposed in previous literature. Regarding the extreme difficulty of analytically solving the FJ equations of active diffusion in confinement, in this thesis we investigate the confined active transport numerically. We transfer the Langevin equations into finite difference equations, and introduce the algorithm of sliding boundary condition for the investigation of confined active diffusion. For the purpose of quantitative characterization, we define two key transport quantifiers: the rectification power and channel diffusivity at the steady state. The simulationUnder the current interests of artificial active particles diffusing in the microscopic geometries, we numerically study the transport and diffusion of Janus micro-swimmers along a narrow periodically corrugated channel. With the motivation of the recent experimental development of the active particles with or without chirality, we introduce the Langevin approach to describe 2D model of the bulk diffusion of active particles proposed in previous literature. Regarding the extreme difficulty of analytically solving the FJ equations of active diffusion in confinement, in this thesis we investigate the confined active transport numerically. We transfer the Langevin equations into finite difference equations, and introduce the algorithm of sliding boundary condition for the investigation of confined active diffusion. For the purpose of quantitative characterization, we define two key transport quantifiers: the rectification power and channel diffusivity at the steady state. The simulation results and analysis of the autonomous transport and diffusivity are displayed, and it is found that characterization functions strongly depend on the self-propulsion mechanism and chirality of the JP, as well as the channel geometry. This simplified model so-far discussed in this thesis can be considered as a stepping stone for more challenging generalizations and a useful reference for the real applications of control techniques.…