A computational fluid dynamic study of intense cephalopod-like motions

The complexity in structure and locomotion of cephalopods, such as the octopus, poses difficulties in modeling and simulation. Their slender arms, being highly agile and dexterous, often involve intense deformations that are hard to simulate accurately, while ensuring numerical stability and low diffusion of the transient motion results. Within the immersed-boundary and the finite-volume frameworks, this paper focuses on geometries performing prescribed motions that reflect cephalopod locomotion. Both numerical approaches are used to determine the mesh requirements that must be employed for sufficiently capturing not only the near wall viscous flow but also the off-body vortical flow field in intense forced motions. The objective is to demonstrate and exploit the generality of the immersed boundary approach to complex numerical simulations of deforming geometries. Incorporation of arm deformation appears to increase the output thrust of a single-arm system. It was further found that sculling motion combined with arm undulation is an effective propulsive scheme for a cephalopod-like arm.