Fig. 2

Figure 2. (a) Definition of cilium tilt angle. The cilia are connected to the ground and the connection point is stationary during the ciliary beating. (b) The dimensions of the flow domain are used as 25 µm × 50 µm. The red line is the ground of the flow domain, which is modeled as a wall with no-slip condition. A non-zero mass flow rate is observed on the yellow line depending on the ciliary motion. (c) The geometric configuration of two cilia with no phase difference (Case 4, in phase). (d) The geometric configuration of two cilia with phase difference (Case 5, out of phase). For the out of phase configuration, the cilium at the right side completes its cycle, while the cilium at the left is at half of the cyclic motion.