. 2012 Jan 20;6(1):014106–014106-14. doi: 10.1063/1.3676068

Figure 4.

Motion of particles with time: The field-of-view is the region between the oscillating end of cilia and top boundary of the unit-cell with the bottom left corner at $(x, y) = (0.5 L, 0.95 L)$ and the top right corner at $(x, y) = (1.55 L, 2 L)$ . The velocity in the channel direction is larger in the direction opposite to the wave than in the direction of the wave. The white curves represent the trajectory of particles and the black dots represent the particles. Particles near the cilia move unidirectionally and show larger displacement, whereas the particles near the top boundary do not show any displacement. An animation of the motion of the fluid particles is added as a supporting information (enhanced online) .