A Flow-Physics-Informed Dynamic Model of Collective Swimming in Fish

            The collective movement of fish in schools is driven not just by behavioral imperatives (such as safety from predators, improved foraging, etc.) and propulsive forces, but also by the hydrodynamic forces induced by the complex flow field encountered by fish swimming in a school. Hydrodynamics also plays a key role in enabling a fish to sense the position/velocity of neighbors and to control its own velocity and heading. Finally, hydrodynamic interactions can be exploited by fish in schools to improve swimming performance. A model of collective swimming that allows the investigation of behavior, as well as hydrodynamic sensing and energetics, could help answer questions related to the behavioral ecology of fish as well as the design of bioinspired swimming systems. In the current study, we present a new model of collective swimming of fish that has three key features: (a) the model is based on the balance of forces and moments on the fish; (b) the model includes interaction with the vortex wakes of fish; (c) the model is parametrized via data from direct numerical simulations (DNS) of a swimming fish. The complex collective swimming patterns that emerge from this model are analyzed and recapitulated against observations. The implications of model predictions for hydrodynamic sensing, control, and hydrodynamic efficiency are also explored.