Optimized hydrodynamic interactions in phalanx school arrays of accelerated thunniform swimmers

Abstract

Optimal fish array hydrodynamics in accelerating phalanx schools are investigated through a computational framework which combines high fidelity Computational Fluid Dynamics (CFD) simulations with a gradient free surrogate-based optimization algorithm. Critical parameters relevant to a phalanx fish school, such as midline kinematics, separation distance and phase synchronization, are investigated in light of efficient propulsion during an accelerating fish motion. Results show that the optimal midline kinematics in accelerating phalanx schools resemble those of accelerating solitary swimmers. The optimal separation distance in a phalanx school for thunniform biologically-inspired swimmers is shown to be around $2L$ (where $L$ is the swimmer's total length). Furthermore, separation distance is shown to have a stronger effect, \textit{ceteris paribus}, on the propulsion efficiency of a school when compared to phase synchronization.