Abstract
By performing numerical simulations of the governing fluids and odorant transport equations, this study identified a relationship between the hydrodynamic interactions and olfactory chemoreception in a fish-like school. Simulations were performed using an in-house developed immersed-boundary method based incompressible Navier-Stokes flow solver coupled with the odorant advection-diffusion equation. From a hydrodynamic performance perspective, it was found that the drag of a trailing fish in a synchronous school could be reduced by up to 18% (relative to an in-line school) by introducing a lateral spacing (L) of 0.2 or 0.4 BL relative to the leader. Detrimental wake interactions in the form of strong high velocity regions produced by the leader intercepting the follower head were eliminated at these larger lateral spacings. However, large lateral spacing also led to suppressed surface odor concentration on the trailing fish hence reducing the trailing fish’s ability to detect the presence of the leading fish through chemoreception. At a moderate lateral spacing of L = 0.2BL, the drag induced by the follower is still lower than for the in-line follower (but slightly higher than for L = 0.4BL) and provides a high odor concentration on the body surface. Thus, the moderate lateral spacing serves as a balance between avoiding the detrimental high velocity regions behind the leader and increasing the odor interaction in an in-line synchronous school.
