Rectified transport of chiral active particles in the two-dimensional channel with varied upper wall

Rectified transport of chiral self-propelled particles is numerically investigated in a two-dimensional channel with varied upper wall. Due to the chirality of active particles, the transversal asymmetry can break the symmetry of the system and induce a longitudinal net transport. It is found that the variation of the channel walls can strongly affect the rectified transport. There exist optimal values of the parameters (the variation parameter, the self-propelled velocity, the angular velocity, and the translational diffusion) at which the scaled average velocity takes its maximal value.