A computational fluid dynamics study of suction feeding fish using chimera overset grids

Suction feeding is one of the most common forms of aquatic prey capture. During a suction feeding event a fish rapidly expands its buccal cavity to create a pressure drop which forces a fluid fiow into the fish mouth. The fluid flow field created during a suction feeding event interacts with prey via hydrodynamic forces and draws the prey into the fish mouth. A knowledge of this fluid flow field and the forces exerted on the prey are crucial to understanding suction feeding. Experiments involving high speed filming have increased this understanding but have limitations. We investigate suction feeding through computational fluid dynamics (CFD) experiments utilizing Chimera overset grids. We validate this approach through comparisons with experiments and previous models and explore how ram swimming affects the fluid flow field. A relationship between ram and the importance of strike accuracy in suction feeding events is found. We explore why most species of suction feeders have flat circular mouths and show these attributes are important for maximizing fluid flow rates and minimizing prey capture times.