In 2005, Professor Michael Bernitsas, of the Department of Naval Architecture and Marine Engineering at the University of Michigan - Ann Arbor, turned his research 180 degrees from what he and others had been working toward. He looked for ways to maximize the effects VIV and control its power rather than suppress its effects. His work resulted in the development of a device that is capable of harnessing the destructive power of VIV in a controllable manner, resulting in generation of clean and renewable electric power in an environmentally compatible way. VIVACE can be placed in a river or ocean current to extract energy from moving water. This converter is unlike any existing technology, as it does not use turbines, propellers, or dams.
The VIVACE Converter uses the well-known phenomenon of vortex induced vibrations (VIV) to convert hydrokinetic energy of underwater currents to electricity. VIV is commonly known as the cause of tremendous damage in aero, civil, mechanical, marine, offshore, and nuclear engineering applications. Ever since Leonardo da Vinci first observed VIV in 1504AD, in the form of “Aeolian Tones,” engineers have been trying to understand VIV and prevent it from damaging equipment and structures. The Tacoma Narrows Bridge collapse in Washington State in 1940 was due to VIV. VIV results from vortices forming and shedding on the downstream side of bluff bodies in a current. Vortex shedding alternates from one side to the other, inducing oscillations to elastic bodies (e.g. cylinders, spheres) or as in the case of the Tacoma Narrows Bridge, torsional vibrations. This fluid-structure interaction phenomenon occurs due to nonlinear resonance of cylinders (or spheres) through vortex shedding lock-in.