Sound waves could support wave energy generation

New research from Cardiff University finds that acoustic waves could support energy generation from waves. The work recognises that waves on the surface of the ocean are often created by a combination of wind raising up water and gravity pulling it back down – sometimes referred to as surface-gravity waves. On the other hand, waves underwater are sound waves produced by phenomena like earthquakes or volcanic eruptions, sometimes thousands of metres below the surface. These acoustic waves travel by compressing and expanding the water, similar to how sound moves through the air, and travel across oceans at the speed of sound in the water before eventually dissipating, while surface waves travel at much lower speeds. This new research looks at the interaction of these two types of wave and the phenomenon of triad resonance.  This is where two acoustic waves transfer energy to a surface wave by matching its frequency, which in turn causes the surface wave to get larger and more powerful (by increasing its amplitude). This opens up the possibility of using an acoustic wave generator to generate sound waves tuned to a particular size and frequency that would enhance (or equally suppress) surface waves. Enhanced waves would enable today’s wave turbines and oscillating water columns (which use wave power to force air through a turbine) to produce more electricity, effectively overcoming their efficiency problem.

More: Wave energy’s huge potential could finally be unlocked by the power of sound – new research

Research paper: Resonant triad interactions of two acoustic modes and a gravity wave | Journal of Fluid Mechanics | Cambridge Core