Power in motion: transforming energy harvesting with gyroscopes

(Press-News.org) Osaka, Japan – Ocean waves are one of the most abundant and predictable renewable energy sources on the planet, yet efficiently harnessing their power remains a major challenge. Traditional devices typically operate efficiently only within a narrow range of wave conditions, highlighting the need for more novel, constructive converters.

Now, one researcher from The University of Osaka has analyzed the feasibility of a novel device for generating wave power. The device, called a gyroscopic wave energy converter (GWEC), was assessed for its potential in providing practical, large-scale energy generation. The findings were published last month in the Journal of Fluid Mechanics.

The GWEC device is capable of generating electricity using the complex motion of a spinning flywheel mounted inside a floating structure. It is this gyroscopic flywheel system that can be tuned to absorb energy efficiently over a broad range of wave frequencies.

The key to absorbing energy lies in gyroscopic precession, which is the motion that occurs when a spinning object is subjected to an external force. As waves cause the floating structure to pitch (move up and down), the rotating flywheel responds by precessing (changing the direction it is spinning in), which drives a generator and consequently produces electricity.

“Wave energy devices often struggle because ocean conditions are constantly changing,” says Takahito Iida, author of the study. “However, a gyroscopic system can be controlled in a way that maintains high energy absorption, even as wave frequencies vary.”

Using linear wave theory, the coupled interactions between ocean waves, the floating body, and the gyroscope were modeled. By carefully analyzing these interactions, the researchers were able to identify optimal control parameters for both the flywheel’s rotational speed and the generator settings. Remarkably, the results demonstrated that the GWEC can achieve the maximum energy absorption efficiency of one half at any wave frequency, providing the system is properly tuned.

“This efficiency limit is a fundamental constraint in wave energy theory,” explains Iida. “What is exciting is that we now know that it can be reached across broadband frequencies, not just at a single resonant condition.”

To validate the linear theory, numerical simulations in both the frequency and time domains were performed. In addition, further time-domain simulations that accounted for nonlinear gyroscopic behavior were also conducted to account for any potential limitations of the device. These simulations showed that the GWEC maintains high efficiency near its resonance frequency, meaning the frequency at which it absorbed wave energy matched the natural pattern of the ocean.

By showing how gyroscopic parameters can be tuned to maximize performance, the study provides a roadmap for developing adaptable and efficient wave energy converters. As scientists search for reliable renewable energy sources to meet climate goals, advances like this one could help unlock the vast, untapped power of the oceans.

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The article, “Linear analysis of a gyroscopic wave energy converter: absorbing half of the wave energy over broadband frequencies,” will be published in the Journal of Fluid Mechanics at https://doi.org/10.1017/jfm.2026.11172

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