Water-permeable scour protection device of the spoiler type and method for evaluating same

Abstract

The application provides a water-permeable disturbance flow type scour protection device and an evaluation method thereof, and relates to the scour protection field.The protection device comprises a protection base and a water-permeable baffle.The protection base is a conical shell with a high middle and a low periphery.The protection base is provided with a central hole for positioning and cooperation with a foundation pile body.A plurality of first water-permeable holes are arranged on the outer side of the protection base and are circumferentially spaced apart about the central hole.The water-permeable baffle is fixed to the outer periphery of the protection base and is provided with a plurality of second water-permeable holes.The water-permeable baffle is further provided with a plurality of grooves in which bionic grass is installed.The protection base and the water-permeable baffle are fixedly connected through a steel truss structure.The steel truss structure is further provided with bionic grass.A plurality of breeding ropes are connected between the upper part of the protection base and the water-permeable baffle.The water-permeable baffle and the protection base play a two-stage energy dissipation role on the water flow, achieve the scour protection effect, and realize the micro-ecological breeding purpose under the combined action of the breeding ropes and the bionic grass.

Description

Technical Field

[0001] This invention relates to the field of scour protection technology, and in particular to a permeable scour protection device and its evaluation method. Background Technology

[0002] Offshore wind turbine foundations in the marine environment cause changes in the surrounding local flow field. Under the combined effects of horseshoe vortex in front of the pile, wake vortex shedding behind the pile, and streamline contraction on both sides, sediment around the foundation is stirred up, resulting in local scouring.

[0003] Scouring reduces the bearing capacity of the foundation. Furthermore, scouring increases the cantilever length, leading to greater horizontal deformation of the wind turbine and increasing the risk of pile foundation overturning. Additionally, the reduced lateral constraint of the pile foundation lowers the natural frequency of the wind turbine structure, making it more susceptible to resonance and affecting turbine stability, thus reducing the fatigue life of the wind turbine unit. Therefore, scouring protection measures are crucial.

[0004] Currently, erosion protection measures are mainly divided into two types: passive protection and active protection. Passive protection aims to improve the seabed's resistance to erosion, generally achieved by laying protective layers, such as riprap protection and protective films, to enhance the seabed's shear resistance. Active protection aims to reduce the erosive power of water flow and decrease the formation of downflow and horseshoe vortices to suppress erosion, such as measures like pile drilling and sacrificial piles. However, existing erosion protection measures, such as riprap, sandbags, and biomimetic grass, are not always effective and still carry the risk of secondary erosion. Furthermore, with the continuous advancement of grid parity for wind power, traditional protection measures involve complex construction procedures, high costs, and high maintenance costs, requiring regular inspections. They also easily impact the surrounding ecological environment, which is not conducive to long-term development.

[0005] In summary, existing protective measures involve complicated procedures, long construction cycles, and are difficult to implement quickly in a short period of time, resulting in high economic costs. Moreover, as the protective effect gradually diminishes over long-term operation, there is a risk of secondary erosion, and the anti-erosion function is unstable, which can easily have adverse effects on the marine ecological environment. Summary of the Invention

[0006] To address the aforementioned problems, the present invention aims to provide a permeable, turbulent scour protection device and its evaluation method, thereby solving the problems of existing protection measures being cumbersome in procedure, long in construction period, difficult to construct quickly in a short time, and high in economic cost; moreover, the protective effect gradually diminishes with long-term operation, there is a risk of secondary scour, the anti-scour function is unstable, and it is easy to cause adverse effects on the marine ecological environment.

[0007] The technical solution of the permeable turbulence-type scour protection device of the present invention is as follows:

[0008] The permeable turbulence-type scour protection device includes a protective base and a permeable baffle. The protective base is a frustoconical shell that is high in the middle and low around the edges. A central hole is provided in the middle of the protective base, which is used for positioning and matching with the foundation pile.

[0009] The outer side of the protective base is provided with a plurality of first water-permeable holes, which are arranged circumferentially about the central hole, and the first water-permeable holes are arranged in multiple layers at intervals along the axial direction of the protective base.

[0010] The permeable baffle is fixedly installed on the outer periphery of the protective base. The permeable baffle has a plurality of second permeable holes, which are arranged at intervals around the protective base. The permeable baffle also has a plurality of grooves, in which bionic grass is installed.

[0011] A steel truss structure is fixedly connected between the protective base and the permeable baffle. Bionic grass is fixed on the steel truss structure. Multiple aquaculture ropes are connected between the upper part of the protective base and the permeable baffle.

[0012] Furthermore, the protective base is a truncated cone shell, the first water-permeable hole is an arc-shaped elongated hole, the length of the first water-permeable hole extends along the circumferential direction of the protective base, and the first water-permeable holes in the same layer are distributed in a radial plane of the protective base.

[0013] Furthermore, multiple permeable baffles are provided, and the multiple permeable baffles are circumferentially spaced on the outer periphery of the protective base, and the interval between two adjacent permeable baffles forms the groove.

[0014] Furthermore, the permeable baffle is an arc-shaped baffle, and multiple permeable baffles are located on the concentric circle of the protective base. The second permeable hole is a vertical elongated hole, and multiple second permeable holes are distributed at intervals on the arc-shaped surface of the permeable baffle.

[0015] Furthermore, the lower interior of the protective base is provided with multiple polyester blocks, each of which is fitted with biomimetic grass.

[0016] Furthermore, fiber ropes are connected between the plurality of polyester blocks, and the fiber ropes form a ring around the inner side of the protective base.

[0017] Furthermore, the height of the protective base is greater than the height of the permeable baffle, and the plurality of aquaculture ropes are arranged radially from the top of the protective base to the upper edge of the permeable baffle.

[0018] The technical solution of the evaluation method for a permeable turbulence-type scour protection device of the present invention is as follows:

[0019] The evaluation method for permeable turbulence protection devices includes the following steps:

[0020] S1. First, determine the permeability P1 of the permeable baffle plate and the permeability P2 of the protective base:

[0021] Based on the permeable area A of the permeable baffle in the direction of the flow. 1-0 The total surface area A of the permeable baffle facing the flow. 1-1 The permeability P1 of the permeable baffle was obtained.

[0022] Based on the permeable area A of the protective base in the direction of the incoming flow. 2-0 The total frontal area A of the protective base 2-2 The water permeability P2 of the protective base was obtained.

[0023] S2. Calculate the influence coefficients f1 and f3 of structural factors on the local scour depth:

[0024] Based on the arc spacing e of the permeable baffle, the circumference diameter D1 of the permeable baffle, the height H1 of the permeable baffle, the bottom diameter D2 of the protective base, the height H2 of the protective base, and the fitting parameters η1 and η2 associated with the structural features, the influence coefficients f1 and f3 are obtained.

[0025]

[0026]

[0027] S3. Calculate the influence coefficient f2 of flow field factors and biomimetic grass factors on local scour depth;

[0028] The coefficient of variation of the flow field is β.

[0029]

[0030] The characteristic parameter of the biomimetic grass is θ, which is related to the length L of the biomimetic grass.

[0031]

[0032] The influence coefficient f2 is obtained.

[0033] f2=β θ ·ε 0.5 ;

[0034] S4. Based on the above influence coefficients f1, f2, and f3, calculate the scour depth reduction efficiency Δ.

[0035]

[0036] Among them, S max S0 represents the maximum local scour depth of the wind turbine foundation under the protected state, while S0 represents the local scour depth of the wind turbine foundation under the unprotected state.

[0037] Beneficial Effects: This permeable, turbulent scour protection device employs a design consisting of a protective base, permeable baffles, a steel truss structure, bionic grass, and aquaculture ropes. The protective base is installed at the foundation piles through a central hole, the permeable baffles are fixed to the outer perimeter of the protective base, and the steel truss structure is fixedly connected between the protective base and the permeable baffles. As the outermost energy dissipation structure, the permeable baffles, through multiple secondary permeable holes and the bionic grass installed in the grooves, provide primary energy dissipation for the water flow.

[0038] The protective base is a frustoconical shell, higher in the middle and lower around the edges. Multiple primary permeable holes on its outer surface disrupt the horseshoe vortex and downward flow in front of the pile, providing secondary energy dissipation for the water flow near the foundation pile. Furthermore, a steel truss structure securely connects the protective base and the permeable baffle, forming a reliable integrated structure. This increases the self-weight of the scour protection device and improves the overall stability of the structure. The biomimetic grass on the steel truss structure further dissipates energy from the water flow between the protective base and the permeable baffle. Additionally, multiple aquaculture ropes connect the upper part of the protective base to the permeable baffle. These ropes can be used for rope-cultured products such as shellfish and algae, and their combined effect with the biomimetic grass achieves the goal of micro-ecological aquaculture within the overall structure.

[0039] This permeable, flow-disrupting scour protection device can be prefabricated at the dock, transported to the designated location by tow, and then hoisted and lowered onto the seabed for rapid assembly. The installation process is simple, the construction period is short, and economic costs are reduced. Moreover, in the initial stage of installation, scour protection mainly relies on permeable baffles and protective bases to dissipate energy from the water flow. As a local ecosystem forms near the pile foundation, barnacles and other organisms can be used to attach and increase the water-blocking area during later operation and maintenance, enhancing the scour protection effect and preventing the device from failing later. This achieves a long-term, stable protective effect and prevents adverse impacts on the marine ecological environment. Attached Figure Description

[0040] Figure 1 This is a three-dimensional schematic diagram of a permeable turbulence-type scour protection device according to a specific embodiment of the present invention;

[0041] Figure 2 This is a schematic diagram of the assembly of the protective base, permeable baffle and steel truss structure in a specific embodiment of the permeable turbulence-type scour protection device of the present invention.

[0042] Figure 3This is a three-dimensional schematic diagram of a permeable baffle in a specific embodiment of the permeable turbulence-type scour protection device of the present invention;

[0043] Figure 4 This is a schematic diagram of the internal structure of the permeable turbulence-type scour protection device in a specific embodiment of the present invention.

[0044] In the diagram: 1-protective base, 10-first water-permeable hole, 11-center hole, 12-polyester block, 2-water-permeable baffle, 20-second water-permeable hole, 21-groove, 3-bionic grass, 4-steel truss structure, 5-breeding rope. Detailed Implementation

[0045] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0046] Specific embodiment 1 of the permeable turbulence-induced scour protection device of the present invention, as follows: Figures 1 to 4 As shown, the permeable turbulence-type scour protection device includes a protective base 1 and a permeable baffle 2. The protective base 1 is a frustoconical shell with a high center and low periphery. A central hole 11 is provided in the center of the protective base 1, which is used for positioning and matching with the foundation pile. Multiple first permeable holes 10 are provided on the outer side of the protective base 1. The multiple first permeable holes 10 are arranged circumferentially around the central hole 11, and the first permeable holes 10 are arranged in multiple layers at intervals along the axial direction of the protective base 1.

[0047] A permeable baffle 2 is fixedly installed on the outer periphery of the protective base 1. The permeable baffle 2 has multiple second permeable holes 20, which are arranged at intervals around the protective base 1. The permeable baffle 2 also has multiple grooves 21, in which bionic grass 3 is installed. A steel truss structure 4 is fixedly connected between the protective base 1 and the permeable baffle 2. The steel truss structure 4 is used to increase the self-weight of the device. Bionic grass 3 is also installed on the steel truss structure 4. Multiple breeding ropes 5 are connected between the upper part of the protective base 1 and the permeable baffle 2.

[0048] This permeable, turbulent scour protection device employs a design consisting of a protective base 1, a permeable baffle 2, a steel truss structure 4, bionic grass 3, and aquaculture rope 5. The protective base 1 is installed at the foundation pile through a central hole 11. The permeable baffle 2 is fixed to the outer periphery of the protective base 1, and the steel truss structure 4 is fixedly connected between the protective base 1 and the permeable baffle 2. As the outermost energy dissipation structure, the permeable baffle 2, through multiple secondary permeable holes 20 on its surface and the bionic grass 3 installed in the groove 21, plays a primary role in dissipating energy from the water flow.

[0049] The protective base 1 is a frustoconical shell, high in the middle and low around the edges. Multiple first permeable holes 10 on its outer side disrupt the horseshoe vortex and downward flow in front of the pile, providing secondary energy dissipation for the water flow near the foundation pile. Furthermore, the steel truss structure 4 is fixedly connected to the protective base 1 and the permeable baffle 2, forming a reliable integral structure. This increases the self-weight of the scour protection device and improves the overall stability of the structure. The biomimetic grass 3 on the steel truss structure 4 further dissipates energy from the water flow between the protective base 1 and the permeable baffle 2. Additionally, multiple aquaculture ropes 5 are connected between the upper part of the protective base 1 and the permeable baffle 2. These ropes can be used for rope-cultured products such as shellfish and algae, and their combined effect with the biomimetic grass 3 achieves the ecological aquaculture purpose of the overall structure.

[0050] This permeable, scour protection device can be prefabricated at the dock, transported to the designated location by tow, and then hoisted and lowered onto the seabed for rapid assembly. The installation process is simple, the construction period is short, and economic costs are reduced. Moreover, in the initial stage of installation, the scour protection mainly relies on the permeable baffle 2 and the protective base 1 to dissipate energy from the water flow. As a local ecosystem forms near the pile foundation, barnacles and other organisms can be used to attach and increase the water-blocking area during later operation and maintenance, thereby enhancing the scour protection effect and preventing the device from failing later. This achieves a long-term and stable protective effect and prevents adverse impacts on the marine ecological environment.

[0051] In this embodiment, the protective base 1 is a frustum conical shell, and the first water-permeable hole 10 is an arc-shaped elongated hole. The length of the first water-permeable hole 10 extends along the circumference of the protective base 1, and the first water-permeable holes 10 in the same layer are distributed in a radial plane of the protective base 1. The protective base 1 adopts the structure of a frustum conical shell, which provides good stability after installation. The first water-permeable hole 10 of the protective base 1 can effectively play a secondary role in turbulence and energy dissipation of water flow.

[0052] The system includes multiple permeable baffles 2, which are circumferentially spaced around the outer periphery of the protective base 1, with the gaps between adjacent permeable baffles 2 forming grooves 21. The permeable baffles 2 are arc-shaped, and are located on concentric circles of the protective base 1. The second permeable holes 20 are vertical elongated holes, and are spaced apart on the arc-shaped surface of the permeable baffles 2.

[0053] The first permeable hole 10 of the protective base 1 is an arc-shaped elongated hole that extends in the circumferential direction of the protective base 1. The second permeable hole 20 of the permeable baffle 2 is a vertical elongated hole that extends in the vertical direction. The extension directions of the first permeable hole 10 and the second permeable hole 20 are perpendicular to each other, which can have different turbulence effects on the water flow. The energy dissipation effect is better after the two permeable structures are superimposed.

[0054] In addition, multiple polyester blocks 12 are provided on the lower inner side of the protective base 1, and biomimetic grass 3 is fixed on each of the multiple polyester blocks 12. Fiber ropes (not shown in the figure) are also connected between the multiple polyester blocks 12, and the fiber ropes form a ring around the inner side of the protective base 1. The biomimetic grass 3 placed inside the protective base 1 can reduce the flow velocity when water flows through it, thus playing a role in sediment deposition and settling, and disrupting the generation of the tail vortex behind the pile.

[0055] The height of the protective base 1 is greater than the height of the permeable baffle 2. Multiple aquaculture ropes 5 are arranged radially from the top of the protective base 1 to the upper edge of the permeable baffle 2. The aquaculture ropes 5 are made of high-strength polyethylene, which has chemical corrosion resistance and is suitable for aquaculture of shellfish and algae. In addition, when water flows over the aquaculture ropes 5, the aquatic organisms affect the development of the wake, thus achieving the purpose of water flow energy dissipation.

[0056] The evaluation method for the above-mentioned permeable turbulence-resistant scour protection device includes the following steps:

[0057] S1. First, determine the permeability P1 of the permeable baffle plate and the permeability P2 of the protective base:

[0058] Based on the permeable area A of the permeable baffle in the direction of the flow. 1-0 The total surface area A of the permeable baffle facing the flow. 1-1 The permeability P1 of the permeable baffle was obtained.

[0059] Based on the permeable area A of the protective base in the direction of the incoming flow. 2-0 The total frontal area A of the protective base 2-2 The water permeability P2 of the protective base was obtained.

[0060] S2. Calculate the influence coefficients f1 and f3 of structural factors on the local scour depth:

[0061] Based on the arc spacing e of the permeable baffle, the circumference diameter D1 of the permeable baffle, the height H1 of the permeable baffle, the bottom diameter D2 of the protective base, the height H2 of the protective base, and the fitting parameters η1 and η2 associated with the structural features, the influence coefficients f1 and f3 are obtained.

[0062]

[0063]

[0064] S3. Calculate the influence coefficient f2 of flow field factors and biomimetic grass factors on local scour depth;

[0065] The coefficient of variation of the flow field is β.

[0066]

[0067] The characteristic parameter of the biomimetic grass is θ, which is related to the length L of the biomimetic grass.

[0068]

[0069] The influence coefficient f2 is obtained.

[0070] f2=β θ ·ε 0.5 ;

[0071] S4. Based on the above influence coefficients f1, f2, and f3, calculate the scour depth reduction efficiency Δ.

[0072]

[0073] Among them, S max S0 represents the maximum local scour depth of the wind turbine foundation under the protected state, while S0 represents the local scour depth of the wind turbine foundation under the unprotected state.

[0074] In this embodiment, taking a conventional large-diameter monopile foundation scour protection device as an example: Substituting the known parameters P1=0.5, P2=0.5, η1=0.75, η2=0.63, D1=10m, D2=6m, H1=12m, H2=8m, e=2m, β=0.8, θ=1.2, ε=0.11 into the scour depth reduction efficiency formula, we obtain Δ=32.7%, that is, the scour depth reduction rate is 32.7%.

[0075] The specific embodiments of the evaluation method for the permeable turbulence-type scour protection device of the present invention are the same as the specific embodiments of the evaluation method for the permeable turbulence-type scour protection device in the specific embodiments of the present invention, and will not be repeated here.

[0076] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of the present invention, and these improvements and substitutions should also be considered within the scope of protection of the present invention.

Claims

1. An evaluation method for a permeable, turbulent scour protection device, characterized in that, The permeable turbulence-type scour protection device includes a protective base and a permeable baffle. The protective base is a frustoconical shell that is high in the middle and low around the edges. A central hole is provided in the middle of the protective base, which is used for positioning and matching with the foundation pile. The outer side of the protective base is provided with a plurality of first water-permeable holes, which are arranged circumferentially about the central hole, and the first water-permeable holes are arranged in multiple layers at intervals along the axial direction of the protective base. The permeable baffle is fixedly installed on the outer periphery of the protective base. The permeable baffle has a plurality of second permeable holes, which are arranged at intervals around the protective base. The permeable baffle also has a plurality of grooves, in which bionic grass is installed. A steel truss structure is fixedly connected between the protective base and the permeable baffle. Bionic grass is fixed on the steel truss structure. Multiple aquaculture ropes are connected between the upper part of the protective base and the permeable baffle. The evaluation method includes the following steps: S1. First, determine the permeability P1 of the permeable baffle plate and the permeability P2 of the protective base: Based on the permeable area A of the permeable baffle in the direction of the flow. 1-0 The total surface area A of the permeable baffle facing the flow. 1-1 The permeability P1 of the permeable baffle was obtained. ; Based on the permeable area A of the protective base in the direction of the incoming flow. 2-0 The total frontal area A of the protective base 2-2 The water permeability P2 of the protective base was obtained. ; S2, Calculate the influence coefficient of structural factors on local scour depth. , : Based on the arc-shaped spacing of the permeable baffle The permeable baffle's circumference diameter D1, the permeable baffle's height H1, the protective base's bottom diameter D2, the protective base's height H2, and the fitting parameters associated with the structural features. , The influence coefficient is obtained. , ; S3. Calculate the influence coefficients of flow field factors and biomimetic grass factors on local scour depth. ; The coefficient of variation of the flow field is , ； The characteristic parameters of biomimetic grass are Its length compared to that of bionic grass Related, Obtain the influence coefficient , ； S4. Based on the above influence coefficients , , The scour depth reduction efficiency was calculated. ; in, This refers to the maximum local scour depth of the wind turbine foundation under protective conditions. This refers to the local scouring depth of the wind turbine foundation caused by water flow in an unprotected state.

2. The evaluation method for the permeable turbulence-type scour protection device according to claim 1, characterized in that, The protective base is a truncated cone shell, the first water-permeable hole is an arc-shaped elongated hole, the length of the first water-permeable hole extends along the circumferential direction of the protective base, and the first water-permeable holes in the same layer are distributed in a radial plane of the protective base.

3. The evaluation method for the permeable turbulence-type scour protection device according to claim 2, characterized in that, The permeable baffle is provided in multiple ways, and the multiple permeable baffles are arranged circumferentially at intervals on the outer periphery of the protective base, and the interval between two adjacent permeable baffles forms the groove.

4. The evaluation method for the permeable turbulence-type scour protection device according to claim 3, characterized in that, The permeable baffle is an arc-shaped baffle, and multiple permeable baffles are located on the concentric circle of the protective base. The second permeable hole is a vertical elongated hole, and multiple second permeable holes are distributed at intervals on the arc-shaped surface of the permeable baffle.

5. The evaluation method for the permeable turbulence-type scour protection device according to claim 1, characterized in that, The lower interior of the protective base is provided with multiple polyester blocks, each of which is fitted with biomimetic grass.

6. The evaluation method for the permeable turbulence-prone scour protection device according to claim 5, characterized in that, Fiber ropes are also connected between the plurality of polyester blocks, and the fiber ropes form a ring around the inner side of the protective base.

7. The evaluation method for the permeable turbulence-prone scour protection device according to claim 1, characterized in that, The height of the protective base is greater than the height of the permeable baffle, and the plurality of aquaculture ropes are arranged radially from the top of the protective base to the upper edge of the permeable baffle.

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