Harnessing the efficiency and maneuverability of multi-fin bio-inspired vehicles
Abstract
Swimming animals use networks of coordinated fins to cruise, accelerate, pivot, and swim backwards. To realize the full potential of bio-inspired autonomous vehicles, more work needs to be done to improve maneuverability and autonomy in three-dimensional multi-fin systems. Much previous work has focused on the steady swimming of one fin in isolation, and some recent work has considered the thrust and efficiency of two-dimensional multi-hydrofoil configurations. It remains unclear, however, how to design three-dimensional multi-fin systems that are optimized for both efficiency and maneuverability. For example, a recent study revealed that two rigid hydrofoils can improve their thrust and efficiency by operating in close proximity – either in the lateral or streamwise direction1. Numerical simulations suggest that these thrust/efficiency benefits can scale to complex geometries, such as dorsal-caudal fin interactions in jack fish2. However, no experiments have considered the flow physics of threedimensional multi-fin layouts, nor have any studies systematically investigated how multi-fin layout affects stability, maneuverability, and autonomy. Much of what is known about maneuverability comes from biological observations of swimming fish3 or from prototyped vehicles4, and the fundamental physical mechanisms of fish-like maneuvers – particularly in multi-fin settings – is vastly underexplored. Some multi-fin configurations may increase efficiency but decrease maneuverability, while others may maximize both efficiency and maneuverability. Understanding where and how these optima exist will require a deeper understanding of the unsteady three-dimensional boundary layers and wake structures within multi-fin systems. Exploring the flow physics of multi-fin systems and how they could improve vehicle autonomy is the goal of the research proposed here. In preparation, we have constructed a unique experimental facility to measure three-dimensional flowfields around untethered propulsors. Using our new setup, we will 1) explore the effects of dorsal-caudal fin interactions on both efficiency and maneuverability in fish-inspired vehicles, 2) measure threedimensional wakes and identity flow features that explain these dorsal-caudal fin interactions, 3) test optimal dorsal-caudal strategies on a bio-inspired vehicle prototype, and 4) publish design strategies for incorporating dorsal-caudal fin interactions into next-generation bioinspired vehicles.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jul 26, 2018
- Source ID
- N000141812537
Entities
People
- Daniel B. Quinn
Organizations
- Office of Naval Research
- United States Navy
- University of Virginia