Modelling anguilliform swimming at intermediate Reynolds number: A review and a novel extension of immersed boundary method applications

There is a considerable body of research literature addressing questions surrounding the biomechanics, internal hydrodynamics, external fluid dynamics and neuronal control behind anguilliform swimming, or swimming with whole body undulations. This research spans experimental studies and a host of modelling efforts from the very simple to the enormously complex. In this paper we focus on models of anguilliform swimming at intermediate Reynolds number. The challenge inherent in these modelling efforts, is the unavoidable inextricability of the three components of the swim-system: neural control, muscle mechanics and fluid dynamics. These components all provide input and feedback one to each other in a nonlinear way. Thus, questions about the kinematics, dynamics or functioning of any part of the swim-system can only be truly answered if the entire swim-system is modeled. This is a formidable task, and so modelling efforts to date have restricted themselves to various aspects of the swim-system. We review current models of anguilliform swimming at intermediate Reynolds number and present a promising new modelling approach using the immersed boundary method. This computational method makes it possible to model the entire swim-system while keeping the computational load within manageable limits.