The fluid flow in the cochlea is driven by a periodic oscillation of a given frequency at the stapes on the upper right side boundary. This excites oscillations on the basilar membrane (BM), which lies horizontally in the center of the domain. Over time, the displacement of the cochlea clearly localizes at a specific BM location which shows that the immersed boundary model captures the frequency selectivity in the cochlea. The fluid velocity field is shown on the left. The fluid velocity is shown on the right, while the BM vertical displacement (magnified) is on the right.