Computational analysis of body shape effect in diamond fish schools*

The propulsive performance of fish like swimmers in schools and individually has been studied thoroughly to understand hydrodynamic interactions found in nature. In this research, we parametrically study the effects of varying the body shape of four carangiform swimmers, schooling in a diamond shape, on their hydrodynamic performance. This study uses a class shape transformation parametrization method to create fish body shapes, independently varying the maximum thickness, location of maximum thickness along the body, leading edge radius, and boattail angle. An in-house immersed boundary method-based incompressible flow solver is then used to compute the performance coefficients and wake structure of the school. Schooling performance is defined in terms of thrust increase, drag reduction, and power consumption relative to a solo swimmer. Our results show how varying body shapes of undulating swimmers causes distinct changes in its performance and wake interactions while in a school. These results will contribute to understanding body shapes in schooling scenarios as well as adding to information used to design bio-inspired underwater robot swarms.