Harness Sea Wave Energy: Focus Waves w/ Diffraction & Floating Breakwaters

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Discussion Overview

The discussion explores the potential of using diffraction to focus sea wave energy through an array of wave-opaque objects, such as floating breakwaters, particularly in coastal areas with uniform wave wavelengths. The implications for wave power generation and surfing are also considered.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • Some participants propose using diffraction principles similar to a zone plate to focus sea wave energy with floating breakwaters.
  • Others suggest that the effectiveness of this approach may depend on the uniformity of wave wavelengths and the ability to adjust grid spacing for diffraction.
  • There is a viewpoint that floating breakwaters may be less effective than more rigid structures that extend below the water surface.
  • One participant expresses skepticism about the feasibility of diffraction due to the incoherence of sea waves across a wide front, suggesting that a curved reflector might be more effective.
  • A later reply questions the definition of "fronts" in the context of wave coherence and proposes measuring coherence at specific beachfront locations.

Areas of Agreement / Disagreement

Participants express a mix of fascination with the idea and skepticism about its practical implementation. Multiple competing views exist regarding the effectiveness of diffraction versus other methods, and the discussion remains unresolved.

Contextual Notes

Participants note limitations regarding the uniformity of wave wavelengths and the coherence of sea waves, which may affect the proposed methods. There are unresolved questions about the specific conditions under which diffraction might be effective.

Rayner
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Would it be possible to use diffraction to focus the energy of sea waves, on the principle of the zone plate (https://en.wikipedia.org/wiki/Zone_plate) but reduced to 2 dimensions? This could be done by an array of wave-opaque objects such as floating breakwaters, particularly along coasts exposed to ocean swells of fairly uniform wavelengths. Tweakable of course by changing the spacing.

Not only might this save the planet by improving the economic feasibility of wave power electrical generation devices, but more importantly could also make surfing possible on days and in places where otherwise it wouldn't be.
 
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Facinating idea. I think the workability will depend strongly on how uniform the wavelengths are and how hard it is to change the grid spacing to adjust the diffraction.

I also think that floating breakwaters may not work as well as more rigid structures extending well below the surface.
 
Dr. Courtney said:
Facinating idea. I think the workability will depend strongly on how uniform the wavelengths are and how hard it is to change the grid spacing to adjust the diffraction.

I also think that floating breakwaters may not work as well as more rigid structures extending well below the surface.

I agree. This is a fascinating idea.

google google google

Drats!

Wave energy gets to the point (Nature)
Water lens' might help to harness the ocean's energy.
11 October 2005
...
Xinhua Hu and Che Ting Chan of the Hong Kong University of Science and Technology say that a forest of pillars standing in orderly rows in shallow water can bend ocean waves by refraction...

google google google

Sweet!

The world’s most terrifying 'SWIMMING POOL'
Ocean simulator replicates enormous storm waves to study tidal power (dailymail.co.uk)
16 July 2014
Fancy a swim in a pool that has waves nine-stories high and currents four times faster than an Olympic swimmer?
That’s what awaits you if you stumble into the state-of-the-art wave pool named FloWave at the University of Edinburgh.
Of course it’s actually designed for engineers to test new technologies for wave turbines, rather than giving confident swimmers a run for their money.
...
 
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OmCheeto said:
I agree. This is a fascinating idea.

google google google

Drats!
google google google

Sweet!
I don't think diffraction will work because the sea waves are not coherent across a wide front. But a curved reflector would work. Similar action can be seen wherever two walls form a corner, giving rough conditions in between.
 
tech99 said:
... sea waves are not coherent across a wide front. ...
How wide is your front?
Are there "fronts" where sea waves are generally coherent?
I may have to abscond with some friends' and relatives' beachfront homes next summer, and measure that for myself. :wink:
 

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