New method for harvesting energy from fluid flow based on undulatory motion

In nature, fish have gained wonderful swimming ability over the thousands of years of evolution. As the fish swims, its body, namely, it’s dorsal or tail fin undulates and then alternating waves are sent down the body towards the tip of the tail. These waves generate a jet in the wake and hence a forward force, namely thrust. Scientific studies have already shown that undulatory swimming is a highly effective means of continuous locomotion and has been successfully adopted in many kinds of robotic fishes currently being developed. However, our latest research found that if wave velocity that defines the undulatory motion of the body or the ‘fin’ is less than a specific value, the fishlike body with undulatory motion also has the capability to harvest kinetic energy from flowing fluid. This finding proposes a new energy-harvesting concept which could offer a new and promising solution to support the long-distance voyage of a biomimetic robotic fish.