Adaptive noise mitigation

Abstract

A noise abatement system for offshore construction may include a foundational pile configured for disposition in a floor of a body of water, an array of piles configured for disposition in the floor of the body of water around the foundational pile, and an array of inflatable balloons coupled to the array of piles and disposed in the body of water. The array of piles may be configured to attenuate sound in the floor of the body of water and the array of inflatable balloons may be configured for disposition around the foundational pile and configured to attenuate sound in the body of water.

Description

Atty. Docket No. 10110-24021 AADAPTIVE NOISE MITIGATIONField of the Disclosure

[0001] The disclosure relates generally to noise abatement systems.Brief Description of Related Technology

[0002] The swift expansion of offshore wind energy installations has escalated concerns regarding underwater noise pollution, which may disrupt marine ecosystems, especially marine mammals like whales. The process of driving foundational piles into the seabed is a significant contributor to this noise, with a considerable portion of the energy radiating through the surrounding seabed and water, adversely affecting marine life. Various noise abatement systems (NAS) have been explored and implemented in offshore wind to mitigate these effects. These range from techniques such as pile casting and force-limiting hammers, designed to prevent noise from emanating from the pile into the water. Another approach involves the deployment of curtain systems, like air bubbles or resonator curtains, which act as barriers to enclose the noise source. However, existing solutions exhibit multiple fundamental problems.

[0003] Without mitigation measures, pile driving generates sound pressure levels which exceed the limit values for the sound exposure and the peak level at distance 750m or 1000m. Generally, the noise is in the range of 10-2000Hz, with the maximum between 100 Hz and 500 Hz. The air bubble curtain was widely used for underwater noise abatement, however, it suffers from a significant drawback for targeting low frequency (<500Hz) cases because the sizes of air bubbles are very hard to control from small to large dimensions. Therefore, hydro sound damper (HSD) was proposed by using encapsulated bubbles. However, its deployment faced significant challenges, because the total dry weight of HSD system can exceed 150 tons, surpassing the load capacity of standard pile grippers used for deployment.

[0004] Existing solutions do not address a low frequency noise and soil propagation path. Recent analysis indicates that while a substantial amount of primary noise radiates directly into the water, a critical low-frequency noise component travels along the seabed-water interface. Mitigating this low-frequency noise through both water and substrate paths is useful to protect marine species like baleen whales. Current strategies such as bubble curtains and hydro-sound damper, focus on addressing noises above 500Hz in the primary (waterborne) noise path, leaving the secondary (soilborne) path and low-frequency noise in both paths insufficiently mitigated.Atty. Docket No. 10110-24021 A

[0005] Existing solutions use static designs for diverse underwater environments. The complexity of commercial pile driving, with its varying pile types, configurations, depths, and seabed conditions, renders one-design-fits-all passive noise abatement designs inadequate. Furthermore, the diverse acoustic needs of marine species in these environments call for a Noise Abatement System (NAS) capable of adjusting to a wide range of auditory sensitivities and frequencies. Such a system would offer bespoke protection to each marine species, ensuring that noise mitigation is as effective and as considerate of marine life as possible.SUMMARY OF THE DISCLOSURE

[0006] In accordance with one aspect of the prese disclosure, a noise abatement system for offshore construction may include a foundational pile configured for disposition in a floor of a body of water, an array of piles configured for disposition in the floor of the body of water around the foundational pile, and an array of inflatable balloons coupled to the array of piles and disposed in the body of water. The array of piles may be configured to attenuate sound in the floor of the body of water and the array of inflatable balloons may be configured for disposition around the foundational pile and configured to attenuate sound in the body of water.

[0007] In accordance with another aspect of the present disclosure, a method of installing a noise abatement system for offshore construction may include driving a plurality of piles in a floor of a body of water such that the plurality of piles are disposed around a foundational pile, anchoring a plurality of balloons to respective ones of the plurality of piles, and inflating the plurality of balloons.

[0008] In accordance with yet another aspect of the present disclosure, a method of controlling a noise abatement system for offshore construction including a foundational pile, a plurality of piles disposed in a floor of a body of water around the foundational pile, and a plurality of balloons disposed in the body of water and anchored to the plurality of piles, may include sensing, by a hydrophone, noise in the body of water, and inflating, by a compressor, one or more of the plurality of balloons to a predetermined pressure based on the noise sensed by the hydrophone.

[0009] In connection with any of the aforementioned aspects, the devices, methods, and systems described herein may alternatively or additionally include any combination of one or more of the following features. The array of piles may be disposed concentrically around the foundational pile. The array of piles may include a plurality of rings of piles disposed around the foundational pile. The array of piles may include in a range of 10 to 150 piles. The array of piles may extend less than 20 feet into the floor of the body of water. A diameter of eachAtty. Docket No. 10110-24021 A of the array of piles may be less than 1 foot. One or more piles included in the array of piles may include a cylindrical body and at least one helical flight extending from the body. The array of inflatable balloons may extend vertically between the floor of the body of water and a surface of the body of water. The array of inflatable balloons may circumscribe the foundational pile. The array of inflatable balloons may include a plurality of horizontal levels disposed vertically between the floor of the body of water and a surface of the body of water. At least one of the plurality of horizontal levels may include a plurality of rings of inflatable balloons circumscribing the foundational pile. The array of inflatable balloons may include a plurality of inflatable balloons including an inflatable body defining an interior and a resonator disposed in the interior. The resonator may include a body defining a resonator cavity and an opening connecting the resonator cavity to the interior of the inflatable balloon. Driving the plurality of piles in the floor of the body of water may comprise driving the plurality of piles such that the plurality of piles are disposed concentrically around the foundational pile. Each of the plurality of piles may comprises a cylindrical body, and a helical flight extending from the cylindrical body. Driving the plurality of piles in the floor of the body of water may comprise rotating the plurality of piles, such that the helical flights of the plurality of piles engage the floor of the body of water. Driving the plurality of piles in the floor of the body of water may comprise driving in a range of 10 to 150 in the floor of the body of water. Inflating the plurality of balloons may comprise inflating the plurality of balloons such that the plurality of balloons circumscribe the foundational pile. Inflating the plurality of inflatable balloons may comprise inflating the plurality of balloons such that the plurality of balloons extend vertically between the floor of the body of water and a surface of the body of water.BRIEF DESCRIPTION OF THE DRAWING FIGURES

[0010] For a more complete understanding of the disclosure, reference should be made to the following detailed description and accompanying drawing figures, in which like reference numerals identify like elements in the figures.

[0011] Figure 1 illustrates a hybrid noise abatement system in accordance with one example of the present disclosure.

[0012] Figure 2 depicts noise abatement via underwater noise transmission reduction in accordance with one example of the present disclosure.

[0013] Figure 3 illustrates a noise abatement system in accordance with one example of the present disclosure.

[0014] Figure 4 depicts inflatable balloon metamaterial attenuation of low-frequency hydro noise in accordance with one example.Atty. Docket No. 10110-24021 A

[0015] Figure 5 depicts a metamaterial-based array of piles in accordance with one example of the present disclosure.

[0016] Figure 6 depicts a mini-pile array attenuating low-frequency vibration in accordance with one example of the present disclosure.

[0017] Figure 7 depicts installation of a hybrid noise abatement system including an array of balloons and an array of piles in accordance with one example of the present disclosure.

[0018] Figure 8 illustrates a method of installing a noise abatement system in accordance with one example of the present disclosure.

[0019] Figure 9 illustrates a method of controlling a noise abatement system in accordance with one example of the present disclosure.

[0020] While the disclosed noise abatement devices, systems, and methods are susceptible of embodiments in various forms, there are illustrated in the drawing (and will hereafter be described) specific embodiments of the invention, with the understanding that the disclosure is intended to be illustrative and is not intended to limit the invention to the specific embodiments described and illustrated herein.DETAILED DESCRIPTION OF THE DISCLOSURE

[0021] Hybrid noise abatement systems that use acoustic metamaterials are described. The disclosed systems are suitable for commercial application during offshore construction of various structures, for example, wind farm construction, bridge construction, building construction, and the like. The disclosed systems leverage a multi-layer inflatable balloon array or curtain as tunable metamaterial resonators to attenuate primary-path noises, complemented by an array of metamaterial piles in the seabed for altering wave propagation to suppress secondary-path noises — a function useful to the protection of marine life. Using vibration feedback from each ring of balloons at various depths, the system targets tunable noise mitigation in a broad frequency band, ensuring adaptive mitigation across different pile conditions and marine habitats. The disclosed systems may provide marine ecosystem protection during offshore wind farm construction. The disclosed systems significantly reduce noise stress and harm to marine life, especially to species that are sensitive to low- frequency sounds, leading to healthier marine ecosystems.

[0022] Both water and seabed noise paths are addressed. The Adaptive Hybrid Noise Mitigation System is configured to simultaneously diminish waterborne and soilborne noises during offshore wind farm installations. The multi-layer balloon curtain may diminish primaryAtty. Docket No. 10110-24021 A noise transmission by up to 15-20 dB (97-99%), and for the metamaterial piles to lessen secondary noise by a minimum of 10 dB (90%).

[0023] The disclosed systems implement an innovative approach to mitigating pile-driving noise during offshore wind farm construction, addressing both waterborne and soilborne acoustic challenges. The disclosed systems utilize acoustic metamaterials or metastructures, which include periodic structures with acoustic properties not found in nature.

[0024] The disclosed noise abatement systems include metamaterial mini-piles and inflatable balloons. The metamaterial mini-piles may be utilized as seafloor anchors for the balloon curtain. The balloons are configured to remain collapsed within the framed structure. The balloons are inflated to an ideal or desired volume for low frequency noise reduction once installed, in which the buoyancy force is held by the metamaterial mini-piles, instead of 100-200 tons of heavy clump weight as in HSD. The inflatable aspect of the disclosed systems also minimizes the system's initial volume and improves the efficiency of both deployment and retrieval operations.

[0025] By harnessing the utility of metamaterials in both the balloon design and pile construction, a unified, efficient noise abatement system is provided. The innovative solution simultaneously mitigates noise transmission through both the waterborne path and the substrate, thereby providing noise abatement in the field of offshore wind farm construction.

[0026] Noise abatement systems for offshore construction, methods of installing noise abatement systems, and methods of controlling noise abatement systems are described. The systems and methods described herein may include an array of piles disposed in the floor of a body of water around a foundational pile and an array of inflatable coupled to the array of piles. The foundational pile may be a vertical support structure that is driven or drilled into the floor of the body of water. For example, the foundational pile may be a monopile configured to support a wind turbine, or may support a bridge, oil rig, building, or any other offshore structure.

[0027] The array of piles may be configured to attenuate sound traveling through the floor (e.g., seabed, lakebed). According to some examples, the array of piles may include in a range of 10 to 110 piles. The array of piles may be disposed around the foundational pile, so as to attenuate noise generated as the foundational pile is driven or drilled into the floor of the body of water. The array of piles may be disposed concentrically around the foundational pile. The array of piles may include a plurality of rings of piles disposed around the foundational pile. The plurality of rings of piles may be staggered or offset from one another.Atty. Docket No. 10110-24021 AThe array of piles may extend less than 20 feet into the floor of the body of water. A diameter of each of the plurality of piles comprising the array of piles may be less than 1 foot.

[0028] In addition to attenuating noise traveling through the earth (e.g., soil) disposed below the body of water, the plurality of piles may anchor the array of inflatable balloons to the floor of the body of water. According to some examples, one or more of the plurality of piles may include a helical flight configured to screw into the floor of the body of water increasing a buoyant force the pile is capable of anchoring. Additionally, or alternatively, the array of piles may act as scour protecting, preventing the earth or floor of the body of water from eroding around the foundational pile.

[0029] The array of balloons may be configured to attenuate sound traveling through the body of water. According to some examples, plurality of balloons may extend vertically between the floor of the body of water and a surface of the body of water. Additionally, or alternatively, the array of balloons may circumscribe the foundational pile. For example, when the array of balloons circumscribe the foundational pile and extend between the floor of the body of water and the surface of the body of water, noise generated during driving or drilling of the foundational pile may be effectively trapped within the array or curtain of balloons and dissipated by the array of balloons.

[0030] According to some examples, the array of balloons may include a plurality of horizontal levels disposed vertically between the floor of the body of water and the surface of the body of water. According to some examples, balloons disposed in different horizontal levels may be inflated to different pressures to attenuate noise or sound having the same or different frequencies. According to some examples, one or more horizontal levels of balloons may include a plurality of rings of balloons circumscribing the foundational pile.

[0031] According to some examples, one or more balloons comprising the array of balloons may include a resonator disposed therein. For example, the balloon may include a body defining a (e.g., hollow) interior and a resonator may be disposed in the interior of the balloon. The resonator may be configured to further attenuate sound generated as the foundational pile is driven or drilled into the floor of the body of water.

[0032] Figure 1 depicts a hybrid noise mitigation or noise abatement system 100 in accordance with one example of the present disclosure. As shown in Figure 1 , the noise abatement system 100 may include an inflatable balloon curtain or an array of inflatable balloons 200 in the body of water 110 and metamaterial mini-piles or an array of piles 300 in the floor 120 of the body of water 110 (e.g., seabed, lakebed) in accordance with one example.Atty. Docket No. 10110-24021 A

[0033] In accordance with one aspect of the disclosure, an integrated hybrid noise abatement system integrates a multi-layer inflatable balloon curtain or an array of inflatable balloons 200 (e.g., metamaterial) in the body of water 110 paired with a mini-pile array or an array of piles 300 (e.g., metamaterial) in the substrate soil of a floor 120 of the body of water . The system is configured to attenuate primary path noise through resonance and suppress secondary path noise through seabed-pile dynamic interaction, which together form an effective noise barrier against noise transmission.

[0034] The disclosed systems may utilize mechanical metamaterials to control low- frequency vibrations induced by ground transportation. The disclosed systems integrate two subsystems with a shared structure that reduces costs and environmental impact. For example, the metamaterial mini-piles or array of piles 300 may serve as anchors in the floor 120 of the body of water 110 (e.g., seafloor, lakefloor) to facilitate the installation of the metamaterial balloon curtain or array of balloons 200, which eliminates or significantly reduces the necessity for heavy clump weights, allowing the array of balloons 200 to maintain the volume needed for effective sub-500 Hz noise reduction. By harnessing the potential of metamaterials in both the array of balloons 200 and the array of piles 300 subsystems, a unified, efficient noise abatement system is provided.

[0035] As shown in Figure 1 , the array of inflatable balloons 200 may be disposed around a foundational pile 150. The foundational pile 150 may be a (e.g., vertical) support structure that is driven or drilled into the floor 120 of the body of water 110. For example, the foundational pile may be configured to support a wind turbine, a bridge, a platform (e.g., for an oil rig or another structure), or any other offshore structure. As described above, the array of balloons 200 may be configured to attenuate noise in the body of water generated as the foundational pile 150 is driven or drilled into the floor 120 of the body of water 110. For example, the array of balloons 200 may use resonance to attenuate and dissipate sounds traveling through the body of water 110. Further, as noted above, the array of piles 300 may be configured to attenuate sound traveling through the floor 120 of the body of water 110 (e.g., soil or earth disposed below the body of water 110. According to some examples, as shown in Figure 1 , a hammer 155 may be used to drive the foundational pile 150 into the floor 120 of the body of water 110.

[0036] The array of balloons 200 may include a plurality of inflatable balloons 210. The array of balloons 200 may form a curtain surrounding the foundational pile 150. For example, as shown in Figure 1 , the array of balloons 200 may extend between the floor 120 of the body of water 110 and a surface 130 of the body of water 110. Additionally, or alternatively, the array of balloons 200 may circumscribe the foundational pile 150. Accordingly, the arrayAtty. Docket No. 10110-24021 A of balloons 200 may form a curtain disposed around the foundational pile 150 configured to dissipate noise generated when the foundational pile is driven or drilled into the floor 120 of the body of water 110. According to some examples, the balloons 210 may be (e.g., substantially) circular and may include may have diameters ranging between 0.05 and 1 meter. For example, the balloons 210 may have diameters ranging between .05 and 0.25 meters.

[0037] According to some examples, as shown in Figure 1 , the array of balloons 200 may include a plurality of horizontal levels of balloons 210 disposed vertically between the floor 120 of the body of water 110 and the surface 130 of the body of water 110. For example, as shown, the plurality horizontal levels of balloons 210 may include a first horizontal level 220 and a second horizontal level 230. The array of balloons may include any number of horizontal levels of balloons 210. As shown the first level 220 of balloons 210 may be disposed above (e.g., closer to the surface 130 of the body of water 110) than the second level 230 of balloons 210. According to some examples, the balloons 210 disposed in the first level 220 and the balloons 210 disposed in the second level 230 may be inflated to different pressures. According to some examples, the balloons 210 disposed in the first level 220 and the balloons 210 disposed in the second level 230 may be inflated to the same pressure.

[0038] Additionally, or alternatively, one or more (e.g., each) horizontal level of balloons, for example, the first level 220 and / or second level 230, may include a plurality of rings of balloons 210 circumscribing the foundational pile 150. For example, as shown, a horizontal layer of balloons 210 may include a first ring 240 of balloons 210, a second ring 245 of balloons, and a third ring 250 of balloons 210. A horizontal level of balloons 210, for example, the first level 220 and / or second level 230 of ballons 210 may include additional or fewer rings circumscribing the foundational pile 150. As shown the first ring 240 of balloons 210 may be an innermost ring of balloons 210. Further, the third ring 250 may be an outermost ring of balloons 210. The second ring 245 of balloons may be disposed between the first ring 240 of balloons 210 and the third ring 250 of balloons 210. According to some examples, a thickness of the array of balloons 200 (e.g., on one side of the foundational pile 150) formed by a plurality of rings included in the horizontal level may have a thickness in a range of 1 meter to 2 meters, for example, in a range of 1 .3 to 1 .5 meters.

[0039] According to some examples of the present disclosure, different rings of balloons 210, for example, disposed in the same horizontal level of balloons 210 may be inflated to different pressures. For example, balloons disposed in different rings of the same horizontalAtty. Docket No. 10110-24021 A level of balloons may be inflated to different pressures so as to attenuate noise at different frequencies or in different ranges of frequencies.

[0040] According to some examples, the noise abatement system 100 may further include one or more air supply conduits 160 coupled to one or more balloons 210 of the array of balloons 200 configured to supply air to an interior of the balloons 210, inflating the balloons 210. According to some examples, as shown, an air supply conduit 160 may be coupled to a plurality of ballons included in a horizontal level of the array of balloons 200. For example, the air supply conduit 160 may fluidly couple one or more balloons 210 to a pressure source, for example, a compressor or a tank containing compressed air for inflating the one or more balloons 210. Further, the noise abatement system may include a controller and / or a valve configured to control a pressure to which the one or more balloons 210 are inflated.

[0041] Figure 2 depicts noise abatement via underwater noise transmission reduction with multi-layer or multiple rings of inflatable balloons 210 in accordance with one example of the present disclosure. As shown in Figure 2, one or more (e.g., each of) the balloons 210 included in an array of balloons, for example, array of balloons 200 described above with respect to Figure 1 , may include an (e.g., inflatable) body 211 defining a (e.g., hollow) interior 212. The hollow interior 212 may be configured to receive air, for example, from air supply conduit 160 for inflating the balloon 210.

[0042] The body 211 of the balloon 210 may be composed of an elastic material. Additionally, or alternatively, the body 211 of the balloon may be comprised of a durable material configured to withstand the harsh marine environment and fatigue from continuous inflation cycles. For example, body 211 may be composed of urethane, hypalon, or PVC synthetic rubbers. According to some examples, each of the balloons 210 may further include a mouth portion of mouth 213 coupled to an air supply conduit 160 and configured to convey air from the air supply conduit 160 to the interior 212 of the balloon 210.

[0043] According to some examples, as shown, one or more of the plurality of balloons 210 may include one or more resonators 215 disposed in the interior 212 of the balloon 210. For example, as shown, two resonators 215 may be disposed in the interior 212 of the balloon 210; however, the present disclosure is not limited thereto, and any number of resonators 215 may be disposed in the interior 212 of the balloon 210. For example, a single resonator 215, three resonators 215, or four resonators 215 may be disposed in the interior 212. The one or more resonators 215 may use resonance to attenuate noise in a body of water.

[0044] As shown in Figure 2, the one or more resonators 215 may include a body 216 defining a (e.g., hollow) resonator cavity, hollow interior of the body 216, and a neck orAtty. Docket No. 10110-24021 A opening 217 connecting the resonator cavity to the (e.g., hollow) interior 212 of the balloon 210. The one or more resonators 215 may be configured to resonate at a specific frequency due to interaction of the given medium (e.g., air) disposed within the cavity of the resonator 215 and the neck or opening 217 connecting the cavity to the interior 212 of the balloon 210. Additionally, the resonant frequency of the resonator 215 may change as a function of the pressure within the balloon 210. According to some examples, the one or more resonators 215 may be Helmholtz resonators.

[0045] In accordance with another aspect of the disclosure, the disclosed systems include robust inflatable balloon resonators 215 based on biospecies-specific acoustics. This aspect involves self-tuning balloons 210 equipped with built-in inflating control to optimize the resonance. For example, the noise abatement system may further include one or more hydrophones 161 configured to sense noise traveling through the body of water and a compressor 162 configured to inflate one or more of the plurality of balloons to one of various predetermined pressures based on the noise sensed by the hydrophone 161 . According to some examples, the noise abatement system may include two or more hydrophones 161 disposed at different depths, for example, coupled to different horizontal levels of the plurality of balloons 210. Each of the hydrophones 161 may be configured to sense a frequency of underwater noise at different depths. The frequency of underwater noise detected by the two or more hydrophones may be used to control the pressures to which one or more balloons 210 disposed in the respective horizontal level at which the hydrophone is disposed are inflated. The balloon curtain or array of balloons, which includes multiple rings of interconnected balloons, may be dynamically inflated to adjust and maintain optimal size to resonate across varying pile driving depths. For example, the noise abatement system may include two or more compressors or one or more valves, such that balloons 210 disposed at different depths, e.g., balloons 210 disposed in different horizontal levels of the balloon array may be inflated to different pressures.

[0046] According to some examples, two or more resonators 215 having different body 216 and / or opening 217 shapes and / or sizes may be encapsulated in the interior 212 of each balloon 210 for superposition of multiple resonances, such that the two or more resonators 215 resonate at different frequencies. Thus, the differently sized resonators 215 may each dissipate noise having different frequencies or wavelengths. This aspect ensures effective noise shielding by maximizing the resonant vibration amplitude and frequency bandwidth.

[0047] Further, in some examples, the resonate frequencies of the one or more resonators 215 may be tailored in real-time to the pile driving process. For example, a pressure of the air in a balloon 210 including one or more resonators 215 may be adjusted or set to one ofAtty. Docket No. 10110-24021 A one or more predetermined pressures based on the noise sensed by the one or more hydrophones 161 , such that the one or more resonators 215 resonate at desired frequencies. Further, the noise abatement system may be configured to adapt to a range of operational variables, such as foundational pile diameter, hammer size, strike frequency, characteristics of the floor of the body or water, for example, soil properties, and the specific type of foundational pile being installed, enhancing its versatility and effectiveness in diverse construction scenarios. Furthermore, acoustic feedback sensors, such as hydrophone(s) 161 may be attached to the deployment structures, for example, the air supply conduit 160, or one or more balloons 210 included in a horizontal level of balloons. This feedback allows for adjusting the pressure and / or sizes of inflatable balloons 210 to the unique acoustic profiles of local marine species, thereby optimizing environmental protection efforts. This aspect may include or involve acoustic telemetry, environmental sensing, and risk assessment for renewable energy.

[0048] Further, in some examples, the noise abatement system may further include a controller 165 in communication with the one or more hydrophones 161 and a pressure source, for example, compressor 162. The controller 165 may include a processor and memory. The memory may be configured to store one or more sets of rules or algorithms for controlling the pressure source and one or more actuators, for example, valves in communication with the pressure source.

[0049] For example, the controller may be configured to control the pressure source and / or one or more actuators or valves coupled to the pressure source to inflate the balloons to a specific pressure or pressures. According to some examples, the controller may control the pressure source to inflate the balloons to a set point based on any one, any combination, or all of: (1) a depth or level of the balloon 210; (2) a ring in which the balloon is disposed; (3) noise sensed by a hydrophone (e.g., a hydrophone disposed at a depth or level corresponding to the balloon; (4) the blow rate of a hammer for driving the foundational pile; or (5) a foundational pile penetration depth (e.g., below the floor of the body of water). According to some examples, the controller 165 may control the pressure or set point of the one or more balloons based on closed loop feedback from the one or more hydrophones 161.

[0050] As shown in Figure 2, the plurality of balloons 210 may be configured to attenuate or dissipate high intensity noise 141 generated when the foundational pile is driven or drilled into the floor of the body of water. Particularly, as shown, high intensity noise 141 incident on the plurality of balloons 210 may be attenuate or dissipated, such that low intensity noise 142 is emitted from the plurality of balloons.Atty. Docket No. 10110-24021 A

[0051] Figure 3 illustrates a noise abatement system 100 in accordance with an example of the present disclosure. According to some examples, the array of balloons 200 may further include one or more cages 260. To mitigate issues such as entanglement in currents and balloon fatigue from continuous inflation cycles, one or more of the plurality of balloons 210 may be enclosed in a cage 260. According to some examples, an air supply line 160 may be coupled to the balloons 210 disposed in a respective one of the cages 260. Additionally, or alternatively, the plurality of balloons 210 disposed in a cage 260 may be inflated so as to have the same pressure. Balloons 210 in different cages 260 may be inflated to have different pressures. As shown in Figure 3, a plurality of cages 260 may be disposed around the foundational pile 150 so as to circumscribe the foundational pile 150. Additionally, or alternatively, the a plurality of cages may be disposed vertically along the foundational pile 150, for example, between the floor of the body of water and the surface 130 of the body of water. Monitoring systems may be used to deliver instant data on ocean currents, underwater noise, and the structural integrity of the balloons, allowing for anticipatory operational adjustments or emergency deflation protocol. Figure 4 depicts inflatable balloon metamaterial attenuation of low-frequency hydro noise in accordance with one example.

[0052] The multi-layered balloon curtain or array of balloons of the disclosed systems exhibits broad control bandwidth. Numerical simulations established the effectiveness of a multi-layered inflatable balloon curtain submerged in water for the attenuation of broadband noise spanning from 300 to 600 Hz. Through the intricate interplay of multiple resonances, depicted in Figure 4, this innovative solution proved adept at significantly reducing noise levels. The simulation involved balloons with diameters ranging from 0.05 to 0.25 meters, and a curtain thickness of approximately 1 .3-1 .5 meters. Notably, a remarkable wave attenuation exceeding 20 dB was observed, underscoring the promising potential of this approach in noise mitigation applications.

[0053] The disclosed systems include two metamaterial-based aspects: (i) a multi-layer inflatable balloon curtain as metamaterial resonators to attenuate the primary-path (waterborne) noise; and (ii) an array of mini-piles (metamaterial) in the seabed for altering wave propagation to suppress secondary-path (soilborne) noise.

[0054] The balloon-based aspect may be configured or optimized for underwater noise mitigation of the primary noise path. The attenuation of underwater sound with various balloon diameters may be simulated to address working mechanisms at various frequencies by using Multiphysics software COMSOL (Figure 4). The resonance frequency for a single bubble of radius a at water depth z can be approximated by fr(z, a) = ^(i+^)05- This modelAtty. Docket No. 10110-24021 A may be supplemented with consideration of balloon thickness and damping properties. Through simulation, the balloon sizes may be configured to reduce piling noise in the target frequency range under different water depths. Moreover, multiple Helmholtz resonators may be encapsulated in a balloon.

[0055] In some cases, a balloon curtain including gradient balloon sizes for underwater sound mitigation effects may be used. The effective impedance change and reflectivity properties associated with the balloon curtain may be numerically determined. The noise mitigation ability may be attributed to low effective impedance and enhanced damping of the balloons in the desired frequency range.

[0056] Multi-layered balloon curtains or balloon arrays may be used for broadband control. The multi-layered inflatable balloon curtain in the water may be used to efficiently attenuate broadband noise from 200-400 Hz through superposition of multiple resonances internally. The sizes of the balloon and internal resonators, the volume of the air content and pressure, the thickness of the balloon curtain and its position relative to the pile on the predicted sound levels are factors or parameters that may be established. The noise reduction may be attributed to acoustic scattering and absorption produced by the mismatch of the acoustic impedances between the seawater and the balloon curtain.

[0057] Figure 5 depicts a metamaterial-based array of piles 300 in accordance with one example of the present disclosure. In accordance with another aspect of the disclosure, the disclosed systems may include a triple-functional mini-pile meta-structure or array of piles 300 for noise abatement, scour protection, and balloon curtain or balloon array anchoring. The metamaterial-based array of piles 300 may be a periodic lattice including for example, concentric and / or staggered rings of piles with lattice pitch, pile diameter, and embedment depth selected to create a phononic band gap that attenuates waves. For example, metamaterial-based array of piles may attenuate Rayleigh-type waves in the 200-500 Hz frequency band. For example, a plurality of mini-piles or piles 310 may be installed around the foundational pile 150. According to some examples, as shown, the plurality of piles 310 may form a concentric array of piles 300 around the foundational pile 150. This intrinsic periodic array of piles 300 may be configured as a metastructure on or in the floor of the body of water (e.g., seabed, lakebed) leading to phonon dispersion with unique band structures, thus confining mechanical sound energy in the metastructure mini-piles.According to some examples, the array of piles 300 may include about 100 piles 310. For example, the array of piles 300 may include in the range of 10 to 150 piles, in the range of 25 to 125 piles, or in the range of 50 to 125 piles. In some embodiments, each of the piles 310 may be composed of metal or a metal alloy. In accordance with other examples, one orAtty. Docket No. 10110-24021 A more (e.g., each of) the piles 310 may be composed on another material, for example, concrete. According to some examples, the piles 310 may be hollow concrete piles, which preserve band-gap performance while requiring less material. The arrangement or orientation of the plurality of piles, for example, the dimensions and / or spacing of the piles may be determined, at least in part, based on a material comprising the plurality of piles.

[0058] The layout pattern, depth, and diameter of the array of piles 300 may be configured and optimized based on the soil types, enabling a controllable formation of omnidirectional band gaps in the desired sub-500 Hz range. For example, a target frequency band-gap (e.g., for attenuation) may be adjusted by varying the offset of stagger of two or more rings of piles 210 included in the array of piles 300. Additionally, the array of piles may be designed in consideration of soil-layer properties at an installation location to achieve improved (e.g., optimal) frequency tuning. According to some examples, a diameter of the plurality of piles 310 may be less than 12 inches, for example, a diameter of the plurality of piles may be between 2 inches and 12 inches, between 4 inches and 12 inches, or between 6 inches and 10 inches. Additionally, or alternatively, a depth (e.g., into the floor of the body of water) which the plurality of piles extend may be less than 25 feet, less than 20 feet, or less than 15 feet. These metamaterial mini-piles may also serve as seafloor anchors to facilitate the installation of the balloon curtain or balloon array.

[0059] According to some examples, as shown in Figure 5, the plurality of piles 310 may be disposed in a plurality of (e.g., concentric) rings around the foundational pile 150. For example, as shown, the array of piles 300 may include a first ring 320 of piles 310, a second ring 330 of piles 310, and a third ring 340 of piles 310. As shown, the first ring 320 may be a ring of piles 310 closest to the foundational pile 150. As shown, the second ring 330 may be a ring disposed outside of and (e.g., directly) adjacent to the first ring 320. Further, the third ring 340 may be a ring disposed outside of and (e.g., directly) adjacent to the second ring 330. Additional or fewer rings of piles 310 may be included in the array of piles 300.

[0060] According to some examples, as shown in Figure 5, the plurality of rings of piles may be offset or staggered relative to one another. For example, a pile 310 in a first ring of piles may be disposed in a gap between piles 310 in a (e.g., directly) adjacent ring of piles 310. The size and orientation of omni-directional games between piles disposed in the same ring and adjacent rings may be varied, so as to tune the array of piles to mitigate noise of a particular frequency or range of frequencies.

[0061] Beyond noise abatement, the disclosed metamaterial pile arrays 300 may be configured to be permanent after installation, aiming for the benefit of scour protectionAtty. Docket No. 10110-24021 A similar to the rock armor layer for the foundational pile of a fixed-bottom wind turbine or another structural support. This scouring phenomenon occurs around the foundation of the foundational pile 150 due to the vortexes by current flow. For example, several offshore wind farms in Europe such as Scroby Sands and Arklow Bank OWFs with monopiles suffered scouring problems that caused structural instability due to the delay of scour protection installation.

[0062] The disclosed permanent pile array 300, due to its coherent deployment as a noise abatement measure with the foundational pile 150, is able to function as a scour protection layer at the outset. Because of its non-intrusion geometry buried in the floor of a body of water (e.g., seafloor, lakebed), it will hold the soil in place and avoid sediment transport, yielding an enhanced structural integrity, just like the root systems surrounding the trees help with reducing the risk of sediment transportation.

[0063] Figure 6 depicts a mini-pile array attenuating low-frequency vibration in accordance with one example of the present disclosure.

[0064] The metamaterial mini-piles of the disclosed systems are useful for addressing low frequency band gaps in the seabed. The use of a solid metamaterial mini-pile array 380 for mitigating low-frequency surface waves has been tested. Mechanical metamaterials have the capability to attenuate surface waves below 500 Hz by optimizing the arrangement of periodic metal piles 385 while taking advantage of the acoustic properties of the multilayered soil. Lab-scale experiments validated numerical models, showcasing transmission reduction up to 15 dB in a wide band gap from 250 to 400 Hz. This data highlights metamaterial ability to confine wave energy and create wide cut-off band gaps, tunable by adjusting the mini-piles' size and layout. These findings support effective low-frequency noise abatement systems for offshore wind farm constructions, along with the development of efficient scalable noise abatement technologies, including a focus on frequencies below 500 Hz to protect marine ecosystems.

[0065] The metamaterial array of piles are directed to noise mitigation in the substrate soil. The array of piles may be configured to address non-homogeneous soil composition. Based on surveys of soil composition and layer thickness at the various construction sites, for example, wind farm sites, the diverse acoustic properties of the multi-layered soil may be taken into account when determining the size (e.g., diameter), depth, and arrangement of the plurality of piles. Phononic dispersion relations in the vicinity of the mini-pile may be determined through frequency analysis of a single mini-pile unit encased within rectangular or trapezoid substrate layers. This unit cell may be discretized with 4-node tetrahedralAtty. Docket No. 10110-24021 A elements to calculate the eigenfrequencies, enabling the analysis of wave propagation for the attenuation. Optimal dimensions for single piles may be assessed for resonance efficiency, tension capacity, and installability. Following this, the arrangement of the array of piles may be simulated to confine low-frequency sound waves effectively. Wave transmission through soil may be compared with metamaterial mini-piles under surveyed and under homogeneous soil conditions, assessing soil-specific optimization's impact on underwater noise paths.

[0066] Figure 7 depicts installation of the disclosed hybrid abatement system including an inflatable balloon curtain or array of ballons and an array of piles in accordance with one example of the present disclosure. According to some examples, as shown in Figure 7, one or more (e.g., each of) the plurality of piles 310 may include a body 311 and one or more helical flights 312 extending from the body 311 . As noted above, the body 311 and or the helical flight 312 may be composed of a metal or metal alloy. Depending on soil conditions in the floor of the body of water it may not be easy to drive the plurality of piles 310 into the floor of the body of water (e.g., seabed, lakebed). Additionally, or alternatively, it may be difficult to overcome the large buoyant force of the array of balloons. Accordingly, instead of excavation and hammering, piles 310 including the outward-extending helical flights 312 may be screwed into the floor of the body or water (e.g., lakebed, seabed). The one or more helical flights 312 extending from the body 311 of the piles 310 may also engage soil in the floor of the body of water, increasing a buoyant force the pile 310 and the array of piles 300, collectively, are capable of anchoring to the floor of the body of water.

[0067] Further, as shown in Figure 7, the noise abatement system 100 may further include a connecting or intermediate structure 350 disposed between the array of piles 300 and the array of balloons 200. The intermediate structure 350 may be configured to connect or couple the array of piles 300 and the array of balloons 200 to one another. According to some examples, the intermediate structure 350 may include one or more linkages 351 extending between respective ones of the plurality of piles 310 and the plurality of balloons 210. According to some examples, the one or more linkages may be solid (e.g., metal, plastic) rods extending between one or more piles 310 and one or more balloons 210. Alternatively, the one or more linkages may be cables extending between one or more piles 310 and one or more balloons 210. According to some examples, when one or more balloons 210 of the array of balloons 200 are disposed in cages, the one or more linkages may extend between one or more piles 310 and a cage enclosing the one or more balloons 210. The intermediate structure 350, including the one or more linkages, may be tensionAtty. Docket No. 10110-24021 A members configured to transmit buoyant uplift (e.g., from inflated balloons) to the array of piles.

[0068] Deployment of a noise abatement system according to the present disclosure may include multiple steps as illustrated in Fig. 7. Initially, a driving rig, commercially available may be used to install one or more piles 310 with balanced torque, is used to screw the piles 310 into the floor of the body of water (e.g., seabed, lakebed). Next, the pre-folded array of balloons 200 may be laid on the floor of the body of water and secured to the array of piles 300. For example, the intermediate structure 350 may be installed between the array of piles 300 and the array of balloons 200. According to some examples, the intermediate structure 350 may be coupled to the array of piles 300 and the array or balloons 200 using a Remotely Operated Vehicle (ROV). Next, the plurality of balloons 310 may be inflated to raise the array of balloons 200 to its operational position. The array of balloons 200 supported by the significant buoyancy force they generate, for example, between 100 and 200 tons, may be anchored by the array of piles 300. Unlike conventional friction piles, the unique design of the piles 310 described herein including helical flights 312 offers superior tension capacity, for example, 10 tons per pile 310 in most floors of the body of water, underscoring the metamaterial piles' triple functions as a noise dampener, a balloon array 200 anchor, and a scour protection for inhibiting soil transport.

[0069] Referring to Figure 8, a method of installing a noise abatement system is illustrated in accordance with one example of the present disclosure. For example, the method of Figure 8 may be used to install the noise abatement system 100 illustrated and described above with respect to Figures 1 and 7. Additional, different, or fewer acts may be provided.

[0070] In an act 810, a plurality of piles comprising the array of piles may be driven into the floor of a body of water. According to some examples, as noted above, a torque may be applied to the plurality of piles as they are driven into the floor of the body of water, such that one or more helical flights extending from a respective one of the plurality of piles is rotated into the floor of the body of water. According to some examples, a hammer may be used to drive the one or more piles into the floor of the body of water. According to some examples of the present disclosure, the plurality of piles may be driven into the floor of the body of water, such that the plurality of piles are disposed concentrically around a foundational pile. According to some examples, in the range of 10 to 150 piles may be driven into the floor of the body of water.

[0071] In an act 820, an array of balloons (e.g., the plurality of balloons) may be anchored to the array of piles (e.g., the plurality of piles). According to some examples, theAtty. Docket No. 10110-24021 A intermediate structure may be installed to anchor the plurality of piles and the plurality of balloons to one another. According to some examples, anchoring the plurality of balloons to the plurality of piles may include coupling one or more linkages, for example, rods or cords, to respective ones of the plurality of piles and the plurality of balloons. According to some examples, the array of balloons may be anchored to the array of piles while the balloons are in an uninflated state.

[0072] In an act 830, the array of balloons (e.g., plurality of balloons) may be inflated. The array of balloons may move to their operational or functional position as they are inflated. For example, the array of balloons may be inflated so as to circumscribe a foundational pile and / or extend between the floor of a body of water and a surface of the body of water. According to some examples, inflating the plurality of balloons may include inflating two or more balloons to different pressures. For example, balloons disposed in different horizontal levels may be inflated to different pressures and / or to be different sizes.

[0073] Referring Figure 9, a method of controlling a noise abatement system is illustrated in accordance with one example of the present disclosure. For example, the method of Figure 9 may be used to control the noise abatement system 100 described above with respect to Figure 1 and 7. Additional, different, or fewer acts may be provided.

[0074] In an act 910, noise in a body of water may be sensed. For example, one or more hydrophones included in the noise abatement system may sense the intensity and or frequency of sound disposed in the body of water. As noted above, according to some examples, two or more hydrophones may be coupled to the noise abatement system at different depths. For example, a hydrophone may be coupled to each of two or more different horizontal levels of balloons included in the array of balloons. According to some examples, the noise abatement system may further include a controller, for example, a processor and / or memory. According to some examples, an intensity and / or a frequency of noise sensed by the one or more hydrophones may be received by the processor and / or stored in the memory.

[0075] In an act 920, one or more ballons included in the array of balloons may be inflated to a predetermined pressure based on the sensed noise. For example, one or more ballons may be inflated to a predetermined pressure based on the frequency of noise sensed by the hydrophone. As described above, the resonant frequency of one or more resonators disposed within a balloon may be varied by varying the pressure of air disposed in the interior of the balloon. Accordingly, the resonant frequency of the one or more resonates may be varied or tuned, by changing the pressure inside the balloon, so as to correspond toAtty. Docket No. 10110-24021 A a frequency of noise sensed by the hydrophone. Accordingly, by inflating the balloon to one or more predetermined pressures, the resonator(s) disposed within the balloon may be tuned to a specific frequency or range of frequencies, so as to more efficiently dissipate noise of that frequency or range of frequencies.

[0076] According to some examples, two or more balloons disposed in different horizontal levels of the array of balloons may be inflated to different predetermined pressures, for example, a first balloon disposed in a first horizontal level of the array of balloons may be inflated to a first predetermined pressure, and a second balloon disposed in a second horizontal level of the array of balloons may be inflated to a second pressure. According to some example, one or more balloons may be inflated to one of a plurality of predetermined pressures based on a depth of the balloon (e.g., below the surface of a body of water) and a frequency of noise detected by a hydrophone. Each of the plurality of predetermined pressures may correspond to a specific resonant frequency or a specific range of frequencies to be mitigated by a resonator disposed in the balloon. For example, the controller may control a compressor to inflate the first level balloons to a first pressure and inflate the second level balloons to a second, different pressure in response to hydrophone signals at the depths corresponding to the first and second levels, respectively.

[0077] Described above are examples of systems for adaptive hybrid noise mitigation in offshore wind turbine construction using metamaterials. The disclosed systems use acoustic metamaterials (artificially designed periodic structures) to provide a multi-layer inflatable balloon curtain as tunable metamaterial resonators to attenuate primary noise paths, as well as an array of metamaterial mini-piles in the seabed for altering wave propagation to suppress the secondary noise path. As described above, the multi-layer inflatable balloon curtain is capable of effectively mitigating the low frequency noised below 500 Hz with a tunable band gap. The metamaterial mini-piles, arrayed concentrically around the monopiles, are capable of confining mechanical sound energy, while also providing permanent scour protection and acting as the anchors for the balloon curtains, thereby eliminating the heavy clump weight of large balloon array.

[0078] The term "about" is used herein in a manner to include deviations from a specified value that would be understood by one of ordinary skill in the art to effectively be the same as the specified value due to, for instance, the absence of appreciable, detectable, or otherwise effective difference in operation, outcome, characteristic, or other aspect of the disclosed methods and devices.Atty. Docket No. 10110-24021 A

[0079] The present disclosure has been described with reference to specific examples that are intended to be illustrative only and not to be limiting of the disclosure. Changes, additions and / or deletions may be made to the examples without departing from the spirit and scope of the disclosure.

[0080] The foregoing description is given for clearness of understanding only, and no unnecessary limitations should be understood therefrom.

Claims

Atty. Docket No. 10110-24021 AWhat is claimed is:1 . A noise abatement system for offshore construction, the system comprising: a foundational pile configured for disposition in a floor of a body of water; an array of piles configured for disposition in the floor of the body of water around the foundational pile, the array of piles further configured to attenuate sound in the floor of the body of water; and an array of inflatable balloons coupled to the array of piles and disposed in the body of water, the array of inflatable balloons configured for disposition around the foundational pile and configured to attenuate sound in the body of water.

2. The system of claim 1 , wherein the array of piles is disposed concentrically around the foundational pile.

3. The system of claim 1 , wherein the array of piles includes a plurality of rings of piles disposed around the foundational pile.

4. The system of claim 1 , wherein the array of piles includes in a range of 10 to 150 piles.

5. The system of claim 1 , wherein the array of piles extend less than 20 feet into the floor of the body of water.

6. The system of claim 1 , wherein a diameter of each of the array of piles is less than 1 foot.

7. The system of claim 1 , wherein one or more piles included in the array of piles includes a cylindrical body and at least one helical flight extending from the body.

8. The system of claim 1 , wherein the array of inflatable balloons extends vertically between the floor of the body of water and a surface of the body of water.

9. The system of claim 1 , wherein the array of inflatable balloons circumscribes the foundational pile.

10. The system of claim 9, wherein the array of inflatable balloons includes a plurality of horizontal levels disposed vertically between the floor of the body of water and a surface of the body of water.Atty. Docket No. 10110-24021 A11 . The system of claim 10, wherein at least one of the plurality of horizontal levels includes a plurality of rings of inflatable balloons circumscribing the foundational pile.

12. The system of claim 1 , wherein the array of inflatable balloons includes a plurality of inflatable balloons including an inflatable body defining an interior and a resonator disposed in the interior.

13. The system of claim 12, wherein the resonator includes a body defining a resonator cavity and an opening connecting the resonator cavity to the interior of the inflatable balloon.

14. A method of installing a noise abatement system for offshore construction, the method comprising: driving a plurality of piles in a floor of a body of water such that the plurality of piles are disposed around a foundational pile; anchoring a plurality of balloons to respective ones of the plurality of piles; and inflating the plurality of balloons.

15. The method of claim 14, wherein driving the plurality of piles in the floor of the body of water comprises driving the plurality of piles such that the plurality of piles are disposed concentrically around the foundational pile.

16. The method of claim 14, wherein each of the plurality of piles comprises: a cylindrical body; and a helical flight extending from the cylindrical body, wherein driving the plurality of piles in the floor of the body of water comprises rotating the plurality of piles, such that the helical flights of the plurality of piles engage the floor of the body of water.

17. The method of claim 14, wherein driving the plurality of piles in the floor of the body of water comprises driving in a range of 10 to 150 in the floor of the body of water.

18. The method of claim 14, wherein inflating the plurality of balloons comprises inflating the plurality of balloons such that the plurality of balloons circumscribe the foundational pile.

19. The method of claim 18, wherein inflating the plurality of inflatable balloons comprises inflating the plurality of balloons such that the plurality of balloons extend vertically between the floor of the body of water and a surface of the body of water.Atty. Docket No. 10110-24021 A20. A method of controlling a noise abatement system for offshore construction including a foundational pile, a plurality of piles disposed in a floor of a body of water around the foundational pile, and a plurality of balloons disposed in the body of water and anchored to the plurality of piles, the method comprising: sensing, by a hydrophone, noise in the body of water; inflating, by a compressor, one or more of the plurality of balloons to a predetermined pressure based on the noise sensed by the hydrophone.21 . The method of claim 20, wherein the plurality of balloons includes a plurality of horizontal levels disposed vertically between the floor of the body of water and a surface of the body of water, and wherein inflating one or more of the plurality of balloons includes inflating a first balloon disposed in a first horizontal level to a first predetermined pressure and inflating a second balloon disposed in a second horizontal level to a second predetermined pressure.

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