Arrangement for concentrating sea waves

Abstract

An arrangement for concentrating sea waves, includes a grid-like structure of stopping and/or delaying elements adapted to influence the amplitude and/or phase of the waves and located in such positions in the water that the elements in interaction with the incident sea waves form an interference pattern which gives a concentration of the wave energy in a limited area (concentration area). When the wave energy is to be utilized for power production, the grid-like element structure is designed to give a concentration of the wave energy in a concentration area located in the short-range field of the element structure. Preferably the elements in the structure are mainly situated in front of the concentration area with respect to the dominant wave incident directions. Moreover, the element structure may have an extension (aperture) which is substantially larger than the wave length of the dominant waves at the location.

I claim: .[.1. A system for concentrating water wave energy, said system comprising an off-shore grid-like means for transforming substantially rectilinear fronts of incident water waves into substantially arch-like water wave fronts with concentrated wave energy in a common central area spaced from said grid-like means, said grid-like means comprising a structure formed of a series of interacting water wave stopping and/or delaying elements arranged substantially transversely of a primary direction of propagation of said incident water waves and said elements being relatively dimensioned such that elements and spacings therebetween in a central portion of said series of elements have larger dimensions in the longitudinal direction of said series than elements and spacings therebetween remote from said central portion..]. .[.2. A system as claimed in claim 1, wherein said common central area is situated behind said grid-like means, as viewed in said primary direction of propagation of said incident water waves..]. .[.3. A system as claimed in claim 2, wherein said concentrated wave energy is to be utilized for power production, and wherein said common central area is located within a sector defined by: ##EQU2## wherein: D max  =the largest dimension of said series of stopping and/or delaying elements; and 
     
        elements..]. .[.4.  A system as claimed in claim 2, wherein said grid-like means further comprises wave-diverging means positioned between said series of elements and said common central area..]. .[.5. A system as claimed in claim 2, further comprising wave reflection means positioned behind said grid-like means and behind said common central area, as viewed in said primary direction of propagation of said incident water waves..]. .[.6. A system as claimed in claim 1, wherein the width of said grid-like means, as measured along said incident water waves, exceeds the largest wave lengths of said waves..]. .[.7. A system as claimed in claim 1, wherein said grid-like means comprises at least one said element in the form of an interacting natural formation, for instance a rock, that may have been artificially shaped to improve interaction with neighboring said elements, for instance by blasting..]. .[.8. A system as claimed in claim 1, wherein at least one of said elements is located below the water surface..]. .[.9. A system as claimed in claim 8, wherein at least one of said elements is resilient to said incident water waves..]. .[.10. A system as claimed in claim 8, wherein at least one of said elements comprises a plate-shaped member which is substantially horizontally oriented in the water at a depth therein that said incident water waves do not break on the member..]. .[.11. A system as claimed in claim 1, wherein at least one of said elements is adjustable in size and shape in a controlled manner..]. .[.12. A system as claimed in claim 1, further comprising means, associated with at least one of said elements, for displacing said at least one element with respect to position and/or 
     
     
        orientation in a controlled manner..]. .Iadd.13.  A lens system for concentrating water wave energy, said system comprising an off-shore grid-like means for transforming substantially rectilinear incident water wave fronts into curved water wave fronts which converge toward a common focal area spaced beyond said grid-like means, said grid-like means comprising a structure extending in a longitudinal direction generally transversely of a primary direction of propagation of said incident water wave fronts, said structure comprising means for changing the phase of said incident water wave fronts by effecting a delaying action on a water wave front passing over said structure, said phase changing means comprising a plurality of delaying elements aligned in said longitudinal direction and completely submerged at a depth such that the water waves do not break on passing over said elements, each said delaying element being shaped and positioned in said longitudinal direction such that said delaying action on a water wave front passing over said element is greater above locations of each said element nearer a central portion of said structure than above locations thereof more remote therefrom, said plurality of delaying elements being shaped and mutually positioned in said longitudinal direction such that said delaying elements form interacting means for creating a greater delaying action nearer said central portion of said structure than remote therefrom, whereby said curved water wave fronts are formed and roll beyond said structure toward said focal area..Iaddend. .Iadd.14. A system as claimed in claim 13, further comprising wave diverging means positioned between said plurality of delaying elements and said focal area. .Iaddend. .Iadd.15. A system as claimed in claim 13, further comprising water wave reflection means positioned behind said structure and behind said focal area, as viewed in said primary direction of propagation of said incident water wave fronts. .Iaddend. .Iadd.16. A system as claimed in claim 13, wherein at least one said delaying element comprises an interacting natural formation, for instance a rock, that may have been artificially shaped to improve 
     
     
        interaction with neighboring said delaying elements..Iaddend. .Iadd.17.  A system as claimed in claim 13, wherein at least one of said delaying elements is resilient to said water waves. .Iaddend. .Iadd.18. A system as claimed in claim 13, wherein at least one of said delaying elements comprising a plate-shaped member extending generally horizontally in the water, portions of said member toward said central portion of said structure extending upwardly in the water to a greater height than portions of said member more remote from said central portion of said structure. .Iaddend. .Iadd.19. A system as claimed in claim 13, wherein the size of at least one of said delaying elements is adjustable. .Iaddend. .Iadd.20. A system as claimed in claim 13, wherein the shape of at least one of said delaying elements is adjustable..Iaddend.