Patent Application
20250223768
The present invention relates generally to wave attenuators for floating structures, and particularly, to a wave attenuation device for converting rotational wave energy of a water body to directional water flow, to promote natural growth of oyster reefs located in the water body.
A floating platform in a water body is generally intended to support a marine vessel or structure carrying a weight of equipment and living quarters for such purposes as fishing, satellite observation, offshore drilling, and landing stages. The floating platforms, such as docks, waterfront buildings or walkways, are required to be as immovable as possible despite movement of waves in the water body. Wave attenuators, also commonly referred to as wave dampeners, are conventionally used to stabilize the floating platforms by attenuating movement of the waves to dampen a vertical motion component of the floating platforms.
Such floating platforms are often located at banks of water bodies. Floating platforms are often supported by wave attenuators. However, high costs of such fixed structures in depths over a hundred feet becomes prohibitive and may affect safety of the floating platforms due to rotational wave energy generated by abrupt movement of the waves during high tide or low tide conditions. Also, floating platforms are prone to natural calamities, such as storms, hurricanes or cyclones.
Storm-resistant floating platforms and marinas exist through a combination of engineering and material mass. However, cost of both materials and installation at a large-scale is far out of reach of most customers, and the installation can fundamentally alter the ecology of the surrounding environment, thereby precluding any efforts to hybridize both the natural ecology and desired infrastructure. Moreover, installation of multiple wave attenuators to support a floating platform may severely affect natural growth of oyster reefs. This also leads to gradual accumulation of layers of sediment below floating platforms, which may lead to a reduction in safety and stability of the floating platforms in the long-term. Presence of water flow is critically important to survival of oyster reefs and the structural integrity of the floating platforms.
Efforts have been made in the past to develop wave dampeners to maintain the water flow below the floating platforms. However, such wave dampeners are typically designed to accrete sediments behind them by allowing water and entrained sediment passage, which significantly reduces water velocity and water flow behind the wave dampeners. This is not desirable for either growth of oyster reefs or small-scale floating platforms that require water flow to maintain depth. In addition, conventional wave dampeners tend to accrete entrained materials, which leads to loss in water flow and prevents sufficient coastal erosion necessary for optimal growth of the marine ecosystem.
Accordingly, there is need for a solution to at least one of the aforementioned problems. For instance, there is an established need for a wave attenuation device that efficiently converts rotational wave energy of a water body to directional water flow, so as to promote natural growth of oyster reefs and prevent sediment accretion, while improving safety parameters.
The present invention is directed to a wave attenuation device for converting rotational wave energy of a water body into directional laminar flow.
In an embodiment, a wave attenuation device includes one or more semi-flexible panels having a second portion inclined with respect to a first portion and a third portion thereof. The wave attenuation device may include a plurality of support pilings for supporting the one or more semi-flexible panels.
In an aspect, a highest point of the plurality of support pilings may be located at a mean low tide height of the water body.
In an aspect, the support pilings may be on a concrete bed positioned at a bottom of a water body.
In an aspect, the one or more panels may be made of an engineered marine board material.
In another embodiment, two or more semi-flexible panels may be spaced apart with respect to each other in a vertical direction. The panels may be suspended horizontally by support pilings.
In an aspect, the two or more semi-flexible panels may be parallel to one another.
In an aspect, the semi-flexible panels may have a total width as measured perpendicular to a general direction of a wave front of one average wavelength.
In an aspect, the panels may be made of a marine board material.
In an aspect, the support pilings may be supported by a concrete base.
In another aspect, each of the panels may include a first portion, a second portion and a third portion. A first end of the second portion may be inclined with respect to the first portion, and a second end thereof may be inclined with respect to the third portion. The first end of the second portion may be located at 20% of a total width of the panel. The second end of the second portion may be located at 80% of the total width of the panel.
In another aspect, the first portion may have a wave-facing edge which faces the direction of propagation of waves.
In yet another aspect, the first portion may be arranged in a horizontal direction. The second portion may be inclined with respect to the first portion with a downward inclination angle ranging from 20-40°. The third portion can extend from the second portion. The third portion may be parallel to the first portion.
In still another aspect, the downward inclination angle may be 30°.
In another aspect, the wave attenuation device may eliminate circular wave movement present within waves, while retaining as much forward water movement as possible, using an accelerated surface.
In another aspect, a space between the two or more semi-flexible panels may be open to flow of water, to enable delivery of food particles to the oyster reefs located in the water body. The wave attenuation device allows waves to flow through the gap between the panels.
In another aspect, the panels are arranged to meet the waves with the least possible resistance, to redirect wave energy into laminar flow. To this effect, a desired water flow is maintained, and a floating structure, such as a dock or a walkway, over the wave attenuation device is more likely to survive any unusual storm events.
In another aspect, the wave attenuation device may be self-adapting to both direction and magnitude of tidal and wave height, and may convert the rotational wave energy to directional laminar flow within predetermined flow velocity parameters. The wave attenuation device may be capable of surviving maximum wave forcing.
In another aspect, the wave attenuation device may be placed below a floating platform or structure located on a water body, such as a lake or sea, while allowing water flow behind it and preventing sediment accretion. This ensures natural growth as well restoration of oyster reef in surrounding areas and protection of a floating structure.
In another aspect, the wave attenuation device converts rotational wave energy of the water body that is not conducive to oyster growth and destroys the floating platform into directional laminar flow, while oysters require to feed and that may be survived by the floating structure at high tides.
In another aspect, the wave attenuation device generates the laminar flow of water within a narrow range to maintain water flow and not accrete sediments. In this way, formation and rehabilitation of oyster reefs is supported and protect of the floating structures is ensured.
In another embodiment, a method of making a wave attenuation device includes using one or more semi-flexible panels having a second portion inclined with respect to a first portion and a third portion thereof, and anchoring the one or more semi-flexible panels with a plurality of support pilings, wherein the support pilings are
These and other objects, features, and advantages of the present invention will become more readily apparent from the attached drawings and the detailed description of the preferred embodiments, which follow.
The preferred embodiments of the invention will hereinafter be described in conjunction with the appended drawings provided to illustrate and not to limit the invention, where like designations denote like elements, and in which:
Like reference numerals refer to like parts throughout the several views of the drawings.
The following detailed description is merely exemplary in nature and is not intended to limit the described embodiments or the application and uses of the described embodiments. As used herein, the word “exemplary” or “illustrative” means “serving as an example, instance, or illustration.” Any implementation described herein as “exemplary” or “illustrative” is not necessarily to be construed as preferred or advantageous over other implementations. All of the implementations described below are exemplary implementations provided to enable persons skilled in the art to make or use the embodiments of the disclosure and are not intended to limit the scope of the disclosure, which is defined by the claims. For purposes of description herein, the terms “upper”, “lower”, “left”, “rear”, “right”, “front”, “vertical”, “horizontal”, and derivatives thereof shall relate to the invention as oriented in
Furthermore, there is no intention to be bound by any expressed or implied theory presented in the preceding technical field, background, brief summary or the following detailed description. It is also to be understood that the specific devices and processes illustrated in the attached drawings, and described in the following specification, are simply exemplary embodiments of the inventive concepts defined in the appended claims. Hence, specific dimensions and other physical characteristics relating to the embodiments disclosed herein are not to be considered as limiting, unless the claims expressly state otherwise.
Shown throughout the figures, the present invention is directed toward a wave attenuation device which eliminates circular wave movement present within a water wave, which is detrimental to establishment of an oyster reef, while retaining as much forward water movement as possible using an accelerated surface.
Referring initially to
The panels 102 may include a first portion 152, a second portion 154 and a third portion 156. A first end of the second portion 154 may be inclined with respect to the first portion 152, with a second end inclined with respect to the third portion 156. The first end of the second portion 154 may be located at 20% of a total width of the panel 102, and the second end of the second portion 154 may be located at 80% of the total width of the panel 102.
The first portion 152 may include a wave-facing edge 158 which faces the direction of propagation of waves 120 of the water body. The first portion 152 of the panel 102 may be arranged in a horizontal direction. The second portion 154 may be inclined with respect to the first portion 152 with an inclination angle ranging from 20-40°. Preferably, the inclination angle is 30°. The third portion 156 extending from the second portion 154 may be parallel to the first portion 152. The panel 102 may include as little front-facing area as possible.
In another embodiment of the invention, the wave attenuation device may include two panels 102 vertically arranged with respect to each other, on the support pilings 104. The panels 102 may be spaced apart with respect to each other in a vertical direction. The space between the top and bottom panels 102 is open to flow of water, to enable delivery of food particles to the oyster reefs located in the water body. To this effect, the waves are allowed to flow through the open spaces between the top and bottom panels 102 which act as shearing plates.
If more than one of panel 102 are being used, they are arranged to meet the wave with the least possible resistance, so as to efficiently redirect the wave energy into laminar flow 122. In this way, a desired water flow can be maintained, and the floating structure installed over the wave attenuation device is more likely to survive unusual storm events. This requires that the wave attenuation device be self-adapting to both the direction and magnitude of waves and storm surge.
Waves generally cannot exceed 120° from peak to trough without breaking. Adjusting the wave attenuating device 100 as it intercepts the waves of different heights allows for the limitation of friction between the waves and the panels 102; thus acceleration of the wave is maintained to maximize exit velocity while eliminating orbiting energy.
In simplified environments with limited fetch, wave equations as provided below describe the physics of the waves the attenuation device 100.
Equation (1) is a form that, through simplifying assumptions, is relevant to shallow waves. Equation (1) describes wave velocity (C) as:
The assumptions yielding simplified form of Equation (1) are reasonable for describing storm waves, where either oyster restoration projects may be suited or where a dock may encounter storm produced wind waves.
By empirical evidence, wave height cannot be greater than 0.143 (L), at which point it will break and accelerate down the wave front. Here, L denotes wavelength. The property of the wave height is used in the design of the attenuation device 100 to shear an on-coming wave and in aggregate produce an accelerating laminar flow. Equation (2) describes the rate of on-coming wave energy:
The total energy over time (and in this way the potential destructiveness) may be predicted by knowing the maximum fetch, i.e., linear distance wind has to work on a water body, sustained wind speed, and the water depth. The maximum and mean wave heights where the fetch can be defined based on fixed parameters. However, these equations do not easily simplify, and wave height values are based on probability. Bottom contour and even small changes in wind speed and direction will affect maximum and mean wave heights. Because of changes, expected wave heights are approximate and based on empirical evidence. Design specifications may include a standard safety factor (Hmax) of 1.3.
Equation (3) describes total energy per unit length of a wave front as:
Those skilled in the art would appreciate that ρ (mass per unit volume of water) may change with temperature and salinity of the water. As H (height) doubles, E (energy) quadruples. This property has implication for the spacing of the lateral shear members of the wave attenuation device 100.
Oyster reefs are made of oyster shell (CaCO3) and floating structures, such as docks or walkways, are typically made of wood. Both oyster reefs and wood are not very dense and have relatively high surface areas. Therefore, the oyster reefs and the floating structures are made of materials that may be easily pushed towards a shore of the water body, or into lower energy areas of a water body. Sediment may be transported towards the shore, or lower energy states, from orbital currents (e.g., low steepness waves). Friction may prevent sediment entrained within a wave from completing the orbit, and thus net transport may be shoreward. Therefore, kelvin waves created by boat-waking, do not significantly affect the docks but prevent oyster restorations from surviving. High wave steepness creates high orbital energy that exceeds friction (or holdfast in the case of oysters) and material becomes suspended in the water column, e.g., waves generated by high wind and low fetch. Suspension of material along with high water during a storm surge destroys docks.
Munch-Petersen equation (4) describes the amount of material moved with a given wave type and size as:
As wave height of the water body increases, different parts of a wave encounters parts of the wave attenuation device 100 at different angles. Accordingly, the wave attenuation device 100 may adjust to the wave height, which is a function of fetch, wind speed, and tidal depth. The panels 102 of the wave attenuation device 100 may be provided in a rotatable manner and pivoted within a limited range to adapt to higher or lower flow regimes. The wave attenuation device 100 may be attached to a bottom surface of the floating structure, and may self-adjust during high tide and extreme weather events.
Oysters do not need protection from natural calamities, but the marine structures attached to the oysters require protection from the calamities. Marine structures like docks may be destroyed during hurricanes due to fixed position above water line and unsupported ‘stranding’ between wave heights, which creates a pressure differential that the docks are not designed to withstand. Therefore, the wave attenuation device 100 may be used to protect marine structures.
The wave attenuation device dampens waves into laminar flow while allowing large volumes of water flow through to feed oysters. The laminar flow additionally prevents sediment from being deposited. Water flows below the bottom panel and the open spaces between the top and the bottom panels of the wave attenuation device, which keeps a large volume of water flowing over the oysters without disruption. Having a high volume of water flow is important to ensure oysters receive sufficient nutrients.
The wave attenuation device 100 is designed to meet the wave with the least possible resistance and redirect the wave energy into directional laminar flow. The wave attenuation device 100 reduces the wave energy hitting oyster reefs while permitting sufficient flow of water which provides nutrients to the sedentary oyster reefs. The wave attenuation device 100 may be used as a specialized cover for protecting the oyster reefs from rotational wave energy of the water body. The wave attenuation device 100 may also be used to protect marinas or other marine structures by significantly reducing wave energy and orbiting energy of the wave particles, to prevent sediment accumulation behind the marine structures.
Since many modifications, variations, and changes in detail can be made to the described preferred embodiments of the invention, it is intended that all matters in the foregoing description and shown in the accompanying drawings be interpreted as illustrative and not in a limiting sense. Thus, the scope of the invention should be determined by the appended claims and their legal equivalents.
| Number | Date | Country | |
|---|---|---|---|
| 63603744 | Nov 2023 | US |
