Turbulent flow system for slowing down scouring erosion of seabed around offshore wind turbine pile foundation and construction method

Abstract

The invention relates to a turbulent flow system for slowing down scouring erosion of a seabed around an offshore wind turbine pile foundation and a construction method, in order to destroy an original downstream flow and a horseshoe vortex system, a wide-range turbulent flow plate is arranged at the position far away from a wind turbine pile foundation body, especially in the leading direction of a reciprocating flow. The more dense and higher spoilers are arranged in the range of one time of the pile diameter around the pile foundation body, and the bed surface around the pile foundation body is mainly protected. The spoilers are designed, the purpose of large-range anti-scouring is achieved in the arrangement mode that multiple measures are combined and multiple devices act jointly, universality is high, and the device can be used for different terrains and different environments and is especially effective for reciprocating flow.

Description

Technical Field

[0001] The invention relates to a flow disturbance system and a construction method for slowing down seabed scouring and erosion around an offshore wind turbine pile foundation, belonging to the technical field of marine engineering structures. Background Art

[0002] Offshore wind energy is a clean, energy-rich, renewable and predictable energy source. Its rational development and utilization are of great significance to alleviating the energy crisis and improving environmental pollution. Offshore wind turbines are widely used, but at the same time they face the risk of pile foundation safety caused by the erosion of the seabed by long-term sea currents.

[0003] After studying water erosion, it was found that the flow around the pile foundation as a marine structure is similar to the flow around a cylinder. The presence of the cylinder creates an adverse pressure gradient, which in turn has a strong impact on the distribution of upstream flow velocity and boundary layer separation. The vortex structure formed by the boundary layer separation caused by the adverse pressure gradient in front of the flow object is called a horseshoe vortex because of its horseshoe shape. Obviously, how to weaken the water flow energy of the horseshoe vortex is an important means to effectively protect the pile foundation. Application No.

[0004] The utility model of 202221854375.0 discloses an offshore wind turbine structure capable of coping with high-intensity scouring in severe weather, including a mounting tube and a pile foundation, wherein a top and a bottom plate are respectively arranged on one side of the mounting tube, wherein the top plate is connected to the outer wall of the mounting tube, and a plurality of connecting ribs are connected between the top plate and the bottom plate, wherein a plurality of step plates are connected between the bottom plate and the top plate on the connecting ribs, and through holes are provided on the top plate, the step plate and the bottom plate, and a buffer assembly for buffering the impact force of seawater is arranged on the base. The first step is to buffer the impact force received by the buffer plate by using the first elastic plate and the second elastic plate, and then the stepped structure of the top plate, the step plate and the floor is used to reduce the flow velocity of the bottom current, so as to prevent the bottom current from scouring the pile foundation, and the stepped structure is used to destroy the horseshoe vortex formed by the current near the pile foundation, so as to finally protect the pile foundation.

[0005] However, in actual working conditions, the formation of horseshoe vortices is very complex, and the impact erosion of water waves in the dominant water flow direction (reciprocating flow direction) needs to be considered. Therefore, the existing technology for preventing water flow from eroding the seabed around the pile foundation still needs to be improved. Summary of the invention

[0006] The present invention provides a spoiler system and a construction method for reducing seabed scour and erosion around offshore wind turbine pile foundations. The spoiler is designed and arranged in a manner that combines multiple measures and multiple devices to achieve the purpose of large-scale scour prevention.

[0007] The technical solution adopted by the present invention to solve its technical problem is:

[0008] A disturbance flow system for slowing down seabed scouring and erosion around an offshore wind turbine pile foundation comprises a pile foundation body, with the bottom center of the pile foundation body as the origin, its cross section is an XOY plane formed by an X-axis and a Y-axis, the central axis direction of the pile foundation body is the Z-axis, and a three-dimensional coordinate system is constructed, wherein the dominant water flow direction is defined as the positive direction of the X-axis;

[0009] Define the diameter of the pile foundation body as D. Around the central axis of the pile foundation body, several layers of concentric circles are distributed outward, which are defined as circle 1, circle 2...circle n, where circle n is the concentric circle farthest from the pile foundation body, and the distance between circle n and the pile foundation body is ≤ 2D;

[0010] Each concentric circle is provided with a number of spoilers along the circumference. On the X-axis, a spoiler is symmetrically provided at a position 4D away from the pile foundation body. Four tangents are drawn from the circle n. One end of each tangent is located at the circle n, and the other end is the spoiler at a position 4D away from the pile foundation body.

[0011] Located in the positive direction and the negative direction of the X-axis, a space composed of a tangent and the circumference of the circle n is formed respectively. In each space, a plurality of rows of spoilers are arranged parallel to the Y-axis direction, and the spacing between adjacent spoilers in the X-axis direction is the same;

[0012] The spoilers are located on several layers of concentric circles, and the height of the spoilers gradually decreases from the origin;

[0013] In the space formed by the tangent and the circumference of circle n, starting from the origin, the height of the spoiler gradually decreases;

[0014] The height of the spoiler is ≤1.5D;

[0015] Furthermore, the spoiler is in a semicircular arc shape, the central angle of the semicircular arc is 120°, the arc surface is arranged perpendicular to the XOY plane, and the concave surface faces the pile foundation body;

[0016] A fixing plate is arranged at the bottom of the spoiler, and a plurality of fixing screws are inserted into the seabed after passing through the fixing plate;

[0017] The fixing plate is a circular plate, and the midpoint of the line between the two sides of the semicircular arc of the spoiler parallel to the XOY plane coincides with the center of the fixing plate;

[0018] Furthermore, with the central axis of the pile foundation body as the center line, four layers of concentric circles are sequentially arranged, that is, n=4, and the distances of each layer of concentric circles from the pile foundation body are 0.5D, 1.0D, 1.5D and 2.0D respectively;

[0019] 12 spoilers are evenly arranged on each concentric circle, with the dominant water flow direction as 0° and the counterclockwise direction as positive. On circle 1 and circle 3, the layout directions of the 12 spoilers are 0°, 30°, 60°, 90°, 120°, 150°, 180°, 210°, 240°, 270°, 300°, and 330° respectively; on circle 2 and circle 4, the layout directions of the 12 spoilers are 15°, 45°, 75°, 105°, 135°, 165°, 195°, 225°, 255°, 285°, 315°, and 345° respectively;

[0020] Furthermore, starting from the pile foundation body, the heights of the spoilers of the four concentric circles are 1.5D, 1.25D, 1D, and 0.75D respectively, and the height of the spoiler closest to circle 4 in the tangent part is 0.5D;

[0021] Further, in the space formed by the tangent line and the circumference of the circle n, spoilers are arranged respectively along the three quartered points of the tangent line, and four rows of spoilers are arranged parallel to the Y-axis direction, and the spoiler at a position 4D away from the pile foundation body is defined as the first row, and the second row, the third row and the fourth row are arranged in sequence;

[0022] In the second column, a spoiler is arranged at the intersection of the Y axis and the X axis; in the third column, a spoiler is arranged at each of the three quarter points of the line between the two spoilers located on the tangent line along the Y axis direction;

[0023] Furthermore, for any disturbance flow plates distributed along the circle n, the center of the semicircular arc corresponding to the central angle coincides with the circumference of the circle n.

[0024] Furthermore, the spoilers located on circle 1 and circle 2 have 8 threaded holes on the fixing plate at the bottom thereof, and the remaining spoilers have 4 threaded holes on the fixing plate at the bottom thereof, and the threaded holes are evenly distributed along the circumference of the fixing plate;

[0025] A fixing screw is inserted into each threaded hole;

[0026] According to the construction method of the spoiler system for slowing down the scouring and erosion of the seabed around the offshore wind turbine pile foundation, the specific steps are as follows:

[0027] Step S1, design the installation points of the spoiler on the concentric circles, take the pile foundation body as the center, design four concentric circles at positions of 0.5D, 1.0D, 1.5D and 2.0D away from the pile foundation body, respectively, and define them as circle 1, circle 2, circle 3 and circle 4, each concentric circle is provided with 12 points along the circumference, the two points on the X-axis in circle 1 are 1-1, the two points on the Y-axis are 1-4, the two points at 30° to the X-axis are 1-2, the two points at 60° to the X-axis are 1-3, the two points on the X-axis in circle 3 are The points are 3-1, the two points on the Y axis are 3-4, the two points at 30° to the X axis are 3-2, the two points at 60° to the X axis are 3-3, the four points at 15° to the X axis in circle 2 are 2-1, the four points at 15° to the Y axis are 2-3, the points 2-2 are evenly distributed between 2-1 and 2-3, the four points at 15° to the X axis in circle 4 are 4-1, the four points at 15° to the Y axis are 4-3, the points 4-2 are evenly distributed between 4-1 and 4-3, and D is the diameter of the pile foundation body;

[0028] Step S2, design the installation point of the external part spoiler, design point 5-1 at two symmetrical points at a distance of 4D from the pile foundation body, the line connecting point 5-1 and point 4-2 is a tangent of circle 4, and points are respectively set at three quarter points of the tangent, starting from 5-1, 5-2, 5-3 and 5-4 are arranged in sequence, point 5-5 is arranged at the perpendicular intersection point of the line formed between the two points 5-2 and the X-axis, point 5-7 is arranged at the perpendicular intersection point of the line formed between the two points 5-3 and the X-axis, and the center position of the line formed by 5-3 and 5-7 is point 5-6;

[0029] Step S3, install the fixing plate in the order of points 4-3, 4-2, 5-4, 5-3, 5-2, 5-1, 3-4, 3-3, 3-2, 4-1, 5-6, and 5-5, and vertically fix the spoiler on the fixing plate, so that the center angle of the concave surface of the spoiler arc is located on the circumference of circle 1 or circle 2 or circle 3 or circle 4;

[0030] Step S4, continue to install the fixing plate in the order of points 2-3, 2-2, 2-1, 3-1, 1-4, 1-3, 1-2, and 1-1, vertically fix the spoiler on the fixing plate, and the center of the circle corresponding to the concave surface of the spoiler arc is located on the circumference of circle 1 or circle 2 or circle 3 or circle 4, completing the construction and installation of the spoiler system.

[0031] Through the above technical solution, compared with the prior art, the present invention has the following beneficial effects:

[0032] 1. The spoiler system for slowing down the scouring and erosion of the seabed around the pile foundation of an offshore wind turbine provided by the present invention is to arrange spoilers layer by layer with the center of the pile foundation body as the center of the circle, and at the same time, tangents are drawn through two symmetrical points outside the formed concentric circles, and spoilers are arranged layer by layer within the tangent range. Most of the water flow is guided to the outside of the tangent, and the internal water flow passes through the multi-layer spoilers, the water flow energy is greatly weakened, and the erosion effect on the seabed soil around the pile foundation is reduced;

[0033] 2. The spoiler system for slowing down the scouring and erosion of the seabed around the pile foundation of an offshore wind turbine provided by the present invention has a guide plate within the concentric circle or tangent range, and the height gradually increases from the outside to the pile foundation body, so that the water flow passes through the outermost spoiler plate, and the part of the water flow close to the seabed loses energy to form a small local horseshoe vortex. In the process of approaching the pile foundation body, due to the continuous increase in the height of the spoiler plate, the height of the water flow forming the local horseshoe vortex is also increasing, and the lost water flow energy is also increasing; the water flow energy that finally reaches the pile foundation body, especially the energy of the bottom water flow, is greatly lost, and the horseshoe vortex formed around the pile foundation body by this part of the water flow is very limited, so that its scouring ability is greatly reduced;

[0034] 3. The spoiler system for mitigating seabed scouring and erosion around offshore wind turbine pile foundations provided by the present invention has a convex surface designed to diffuse the impact water flow, so that the impact water flow retains most of its energy and momentum after impacting the spoiler, thereby reducing the energy and impulse exerted by the impact water flow on the spoiler when impacting the spoiler;

[0035] 4. The construction method of the spoiler system for reducing seabed scouring and erosion around offshore wind turbine pile foundations provided by the present invention follows the principle of installation sequence from outside to inside, and is divided into multi-layer progressive construction. The outer spoiler is installed first, and the acceleration phenomenon and water flow turbulence that may be caused by water flow impacting the spoiler are fully considered to avoid interference with the installation of other spoilers, thereby providing more stable water flow conditions for the installation of internal spoilers. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0037] Figure 1 It is a stereoscopic diagram of a flow disturbance system for mitigating seabed scour and erosion around an offshore wind turbine pile foundation provided by the present invention;

[0038] Figure 2 It is a top view of the spoiler system for mitigating seabed scour and erosion around offshore wind turbine pile foundations provided by the present invention;

[0039] Figure 3 It is a three-dimensional structural diagram of a spoiler in a spoiler system for mitigating seabed scour and erosion around an offshore wind turbine pile foundation provided by the present invention;

[0040] Figure 4It is a top view of the installation of an internal spoiler in a spoiler system for mitigating seabed scour and erosion around an offshore wind turbine pile foundation provided by the present invention;

[0041] Figure 5 The invention is a top view of the installation of a peripheral spoiler in a spoiler system for alleviating seabed scour and erosion around an offshore wind turbine pile foundation provided by the present invention.

[0042] In the figure: 1 is the pile foundation body, 2 is the spoiler, 3 is the fixing screw, and 4 is the solidified soil. DETAILED DESCRIPTION

[0043] The present invention will now be described in further detail with reference to the accompanying drawings. In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "left side", "right side", "upper part", "lower part", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and "first", "second", etc. do not indicate the importance of the components, and therefore cannot be understood as a limitation on the present invention. The specific dimensions used in this embodiment are only for illustrating the technical solution by example, and do not limit the scope of protection of the present invention.

[0044] As explained in the background technology, weakening the water flow energy of the horseshoe vortex is an important means to prevent the erosion of the seabed around the pile foundation. Therefore, the present application provides a spoiler system for slowing down the scouring and erosion of the seabed around the pile foundation of an offshore wind turbine. The spoiler system is arranged in a formation with spoilers 2 to destroy the original downward flow and the horseshoe vortex.

[0045] In general, the spoiler system provided by the present application includes two parts, the first part is defined as a concentric circle part, which is arranged close to the pile foundation body 1, and the second part is defined as a tangent part, which is located outside the concentric circle part. For the convenience of explanation, the bottom center of the pile foundation body is taken as the origin, its cross section is the XOY plane formed by the X-axis and the Y-axis, and the central axis direction of the pile foundation body is the Z-axis, and a three-dimensional coordinate system is constructed, in which the dominant water flow direction is defined as the positive direction of the X-axis.

[0046] In the concentric circle part, the diameter of the pile foundation body is defined as D. Around the central axis of the pile foundation body, several layers of concentric circles are distributed outward, which are defined as circle 1, circle 2...circle n, respectively. Among them, circle n is the concentric circle farthest from the pile foundation body, and the distance between circle n and the pile foundation body is ≤2D.

[0047] In the tangent part, each layer of concentric circles is provided with a number of spoilers along the circumference. On the X-axis, a spoiler is symmetrically provided at a position 4D away from the pile foundation body. Four tangents are drawn from circle n, one end of each tangent is located at circle n, and the other end is the spoiler at a position 4D away from the pile foundation body. In the positive and negative directions of the X-axis, a space formed by the tangent and the circumference of circle n is formed respectively. In each space, a number of rows of spoilers are arranged parallel to the Y-axis direction, and the spacing between adjacent guide plates in the X-axis direction is the same.

[0048] The range of the distance between circle n and the pile foundation body and the tangent angle are set here because, generally speaking, under strong wave and flow dynamics, the maximum scour depth around the pile is about 1.0-1.2 times the pile diameter, and the underwater repose angle of seabed sediment is 31-34°. Therefore, it is considered that the radius of the scour pit is about 1.73 times the scour depth. Taking all factors into consideration, the distance between circle n and the pile foundation body is ≤2D, and the other end of the tangent is 4D away from the pile foundation body.

[0049] The whole system looks like Figure 2 As shown, a horseshoe arrangement is adopted. The water flows through the spoilers at the tangent part, and the water flows are guided to both sides of the spoilers layer by layer. Most of the water flows are guided to the outside of the tangent. The part of the water flow close to the seabed loses energy to form a small local horseshoe vortex. The internal water flows through multiple layers of spoilers, and the accelerated flow formed is guided again on the upstream surface of the spoiler close to the pile foundation body. The water flow energy is greatly weakened, and the erosion effect on the seabed soil around the pile foundation is reduced.

[0050] Taking into account the spoiler effect, material cost and installation period, it is preferred that four layers of concentric circles are arranged in sequence with the central axis of the pile foundation body as the center line, that is, n=4, and the distance between each layer of concentric circles and the pile foundation body is 0.5D, 1.0D, 1.5D and 2.0D respectively; 12 spoilers are evenly arranged on each layer of concentric circles, with the dominant water flow direction as 0° and the counterclockwise direction as positive, and 12 spoilers are arranged on circle 1 and circle 3. The layout positions of the plates are 0°, 30°, 60°, 90°, 120°, 150°, 180°, 210°, 240°, 270°, 300°, and 330° respectively. On circle 2 and circle 4, the layout positions of the 12 spoilers are 15°, 45°, 75°, 105°, 135°, 165°, 195°, 225°, 255°, 285°, 315°, and 345° respectively.

[0051] In the space formed by the tangent and the circumference of circle n, spoilers are arranged respectively along the three quartered points of the tangent, and four rows of spoilers are arranged parallel to the Y-axis direction. The spoiler at a position 4D away from the pile foundation body is defined as the first row, and the second row, third row and fourth row are arranged in sequence; in the second row, a spoiler is arranged at the intersection of the Y-axis and the X-axis; in the third row, a spoiler is arranged at each of the three quartered points along the Y-axis direction on the line connecting the two spoilers on the tangent.

[0052] In the above preferred arrangement method, the tangent part focuses on protecting against the impact erosion of the reciprocating flow. The spoiler first resists the incoming water flow and disperses the water flow to both sides. The spoiler of the concentric circle part resists the dispersed water flow and continues to protect against water erosion from all directions. While maintaining the required spoiler effect, the number of spoilers used can be reduced, the material cost and the installation cycle can be reduced, and the economic benefit can be maximized.

[0053] After the spoiler layout design of the system is completed, the height of the spoiler also needs to be reasonably designed. Figure 1 As shown in the figure, the height of the spoilers located on several layers of concentric circles gradually decreases from the origin; in the space formed by the tangent and the circumference of circle n, the height of the spoilers gradually decreases from the origin. This is because in the process of approaching the pile foundation body, due to the continuous increase in the height of the spoiler, the height of the water flow forming the local horseshoe vortex is also increasing, and the water flow energy consumed is also increasing. The water flow energy that finally reaches the pile foundation body, especially the energy of the bottom water flow, is greatly consumed, and the horseshoe vortex formed around the pile foundation by this part of the water flow is very limited, which greatly reduces its scouring ability.

[0054] According to the existing physical model experiments, PIV observations show that diversion occurs at 1.5D on the water-facing side of the pile. Water below this value flows downward, producing a scouring effect. Therefore, the height of the spoiler is set to be ≤1.5D. Preferably, considering that there is no requirement for the outermost spoiler (lowest height), and also considering the material cost and spoiler effect, starting from the pile foundation body, the heights of the four concentric circles of spoilers are 1.5D, 1.25D, 1D, and 0.75D respectively, and the height of the spoiler closest to circle 4 on the tangent part is 0.5D.

[0055] In order to achieve the best spoiler effect, the present application also provides a schematic diagram of the structure of the spoiler, such as Figure 3-Figure 5As shown, the spoiler is in the shape of a semicircle, and the central angle of the semicircle is 120°. The arc surface is perpendicular to the XOY plane, and the concave surface faces the pile foundation body. The orientation of the spoiler is designed to protect the seabed around the pile foundation to the greatest extent. The convex outward design will diffuse the impact water flow, so that the impact water flow retains most of the energy and momentum after impacting the spoiler, reducing the energy and impulse of the impact water flow on the spoiler when impacting the spoiler. Therefore, this helps to reduce the need for fixing the spoiler, reduce maintenance costs, and improve the stability and service life of the structure.

[0056] When the spoiler is installed and fixed, a fixing plate is set at the bottom of the spoiler. There are many ways to fix it, and it only needs to be firm. The fixing plate is a circular plate, and the midpoint of the line between the two sides of the semicircular arc of the spoiler parallel to the XOY plane coincides with the center of the fixing plate. If the spoiler is distributed along the circle n, the center of the semicircular arc corresponding to the central angle coincides with the circumference of the circle n.

[0057] Several fixing screws 3 are inserted into the seabed after passing through the fixing plate to fix the spoiler. According to the actual working conditions, the installation form of the fixing screws is also adjusted accordingly. The spoilers located on circle 1 and circle 2 are Figure 4 As shown, 8 threaded holes are opened on the fixing plate at the bottom, and the remaining spoilers, Figure 5 As shown, four threaded holes are opened on the fixing plate at the bottom, and the threaded holes are evenly distributed along the circumference of the fixing plate, and a fixing screw is inserted in each threaded hole.

[0058] This is because the spoiler around the pile foundation is high, and the force and overturning moment it bears are relatively large, so a higher fixing capacity is required, and more fixing screws are needed to ensure the stability and durability of the spoiler. In the peripheral area, since the force area and force size are smaller, the overturning moment is also smaller, and the use of fixing screws can be reduced, which not only saves costs, but also reduces the difficulty of installation.

[0059] Finally, the present application also provides a construction method for the spoiler system for reducing seabed scour and erosion around offshore wind turbine pile foundations. The entire construction and installation sequence follows the principle of from the outside to the inside, and is divided into multi-layer progressive construction. The outer spoiler is installed first, which can provide more stable water flow conditions for the installation of the internal spoiler.

[0060] Before the construction of the offshore wind turbine pile foundation, a detailed on-site survey is conducted, including seabed topography, current direction and speed, etc., and the layout area of ​​the spoiler is planned to ensure that the layout area can effectively cover the seabed around the wind turbine pile foundation. The positioning system is used to determine the exact position of the pile foundation body, and the center point of the wind turbine pile foundation body is marked on the seabed as a reference point for the subsequent layout of the spoiler. At the same time, the mud and sand around the pile foundation body are processed and turned into hardened seabed soil, which can be reinforced with solidified soil 4.

[0061] The specific steps are:

[0062] Step S1, design the installation points of the spoiler on the concentric circles, take the pile foundation body as the center, design four concentric circles at positions of 0.5D, 1.0D, 1.5D and 2.0D away from the pile foundation body, respectively, and define them as circle 1, circle 2, circle 3 and circle 4, each concentric circle is provided with 12 points along the circumference, the two points on the X-axis in circle 1 are 1-1, the two points on the Y-axis are 1-4, the two points at 30° to the X-axis are 1-2, the two points at 60° to the X-axis are 1-3, the two points on the X-axis in circle 3 are The points are 3-1, the two points on the Y axis are 3-4, the two points at 30° to the X axis are 3-2, the two points at 60° to the X axis are 3-3, the four points at 15° to the X axis in circle 2 are 2-1, the four points at 15° to the Y axis are 2-3, the points 2-2 are evenly distributed between 2-1 and 2-3, the four points at 15° to the X axis in circle 4 are 4-1, the four points at 15° to the Y axis are 4-3, the points 4-2 are evenly distributed between 4-1 and 4-3, and D is the diameter of the pile foundation body;

[0063] Step S2, design the installation point of the external part spoiler, design point 5-1 at two symmetrical points at a distance of 4D from the pile foundation body, the line connecting point 5-1 and point 4-2 is a tangent of circle 4, and points are respectively set at three quarter points of the tangent, starting from 5-1, 5-2, 5-3 and 5-4 are arranged in sequence, point 5-5 is arranged at the perpendicular intersection point of the line formed between the two points 5-2 and the X-axis, point 5-7 is arranged at the perpendicular intersection point of the line formed between the two points 5-3 and the X-axis, and the center position of the line formed by 5-3 and 5-7 is point 5-6;

[0064] Step S3, install the fixing plate in the order of points 4-3, 4-2, 5-4, 5-3, 5-2, 5-1, 3-4, 3-3, 3-2, 4-1, 5-6, and 5-5, and vertically fix the spoiler on the fixing plate, so that the center angle of the concave surface of the spoiler arc is located on the circumference of circle 1 or circle 2 or circle 3 or circle 4;

[0065] Step S4, continue to install the fixing plate in the order of points 2-3, 2-2, 2-1, 3-1, 1-4, 1-3, 1-2, and 1-1, vertically fix the spoiler on the fixing plate, and the center of the circle corresponding to the concave surface of the spoiler arc is located on the circumference of circle 1 or circle 2 or circle 3 or circle 4, completing the construction and installation of the spoiler system.

[0066] According to the installation sequence provided in step S3 and step S4, the acceleration phenomenon and water flow turbulence that may be caused by water flow impacting the spoiler are mainly considered to avoid interfering with the installation of other spoilers. Because the outer layer has provided necessary protection for the inner part, after the spoiler on the outer part is installed and fixed first, the installation of the inner spoiler will be easier. This installation sequence helps to improve construction efficiency and reduce risks during the installation process.

[0067] After the construction is completed, the stability of the spoiler is monitored regularly and necessary maintenance is carried out, including the position, angle and fixing of the spoiler. All data during the spoiler installation process is recorded, including the installation position, installation time, number of fixing screws used, etc. The monitoring data is analyzed to evaluate the spoiler installation effect and provide a basis for subsequent optimization.

[0068] In summary, the arrangement of the spoiler system for slowing down the scouring and erosion of the seabed around the offshore wind turbine pile foundation provided by this application is to destroy the original downward flow and horseshoe vortex system, set a wide range of spoilers far away from the wind turbine pile foundation body, especially in the dominant direction of the reciprocating flow; set more dense and higher spoilers within a range of one times the pile diameter around the pile foundation body, focusing on protecting the bed surface around the pile foundation body. It has strong universality and can be used in different terrains and environments, especially effective for reciprocating flow.

[0069] It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as those generally understood by those skilled in the art to which this application belongs. It should also be understood that terms such as those defined in common dictionaries should be understood to have meanings consistent with the meanings in the context of the prior art, and will not be interpreted with idealized or overly formal meanings unless defined as herein.

[0070] The meaning of "and / or" described in this application means that the situations where each exists alone or both exist at the same time are included.

[0071] The term “connection” as used in this application may mean a direct connection between components or an indirect connection between components via other components.

[0072] Based on the above ideal embodiments of the present invention, the relevant staff can make various changes and modifications without departing from the technical concept of the present invention through the above description. The technical scope of the present invention is not limited to the contents of the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A flow disturbance system for slowing down seabed erosion around an offshore wind turbine pile foundation, comprising a pile foundation body, characterized in that: The center of the bottom surface of the pile foundation body is taken as the origin, its cross section is the XOY plane formed by the X-axis and the Y-axis, the central axis direction of the pile foundation body is the Z-axis, and a three-dimensional coordinate system is constructed, in which the dominant water flow direction is defined as the positive direction of the X-axis; Define the diameter of the pile foundation body as D. Around the central axis of the pile foundation body, several layers of concentric circles are distributed outward, which are defined as circle 1, circle 2...circle n, where circle n is the concentric circle farthest from the pile foundation body, and the distance between circle n and the pile foundation body is ≤ 2D; Each concentric circle is provided with a number of spoilers along the circumference. On the X-axis, a spoiler is symmetrically provided at a position 4D away from the pile foundation body. Four tangents are drawn from the circle n. One end of each tangent is located at the circle n, and the other end is the spoiler at a position 4D away from the pile foundation body. Located in the positive direction and the negative direction of the X-axis, a space composed of a tangent and the circumference of the circle n is formed respectively. In each space, a plurality of rows of spoilers are arranged parallel to the Y-axis direction, and the spacing between adjacent spoilers in the X-axis direction is the same; The spoilers are located on several layers of concentric circles, and the height of the spoilers gradually decreases from the origin; In the space formed by the tangent and the circumference of circle n, starting from the origin, the height of the spoiler gradually decreases; The height of the spoiler is ≦1.5D.

2. The flow disturbance system for mitigating seabed scour and erosion around offshore wind turbine pile foundations according to claim 1 is characterized by: The spoiler is in a semicircular arc shape, the central angle of the semicircular arc is 120°, the arc surface is arranged perpendicular to the XOY plane, and the concave surface faces the pile foundation body; A fixing plate is arranged at the bottom of the spoiler, and a plurality of fixing screws are inserted into the seabed after passing through the fixing plate; The fixing plate is a circular plate, and the midpoint of a line between two side edges of the semicircular arc of the spoiler parallel to the XOY plane coincides with the center of the fixing plate.

3. The flow disturbance system for mitigating seabed scour and erosion around offshore wind turbine pile foundations according to claim 2 is characterized by: With the central axis of the pile foundation as the center line, four layers of concentric circles are sequentially arranged, that is, n=4, and the distances of each layer of concentric circles from the pile foundation body are 0.5D, 1.0D, 1.5D and 2.0D respectively; Twelve spoilers are evenly arranged on each concentric circle, with the dominant water flow direction as 0° and the counterclockwise direction as positive. On circle 1 and circle 3, the layout directions of the 12 spoilers are 0°, 30°, 60°, 90°, 120°, 150°, 180°, 210°, 240°, 270°, 300° and 330° respectively. On circle 2 and circle 4, the layout directions of the 12 spoilers are 15°, 45°, 75°, 105°, 135°, 165°, 195°, 225°, 255°, 285°, 315° and 345° respectively.

4. The flow disturbance system for mitigating seabed scour and erosion around offshore wind turbine pile foundations according to claim 3 is characterized by: Starting from the pile foundation body, the heights of the spoilers of the four concentric circles are 1.5D, 1.25D, 1D, and 0.75D respectively, and the height of the spoiler closest to circle 4 on the tangent part is 0.5D.

5. The flow disturbance system for mitigating seabed scour and erosion around offshore wind turbine pile foundations according to claim 2 is characterized by: In the space formed by the tangent line and the circumference of the circle n, spoilers are arranged along the three quarter points of the tangent line, and four rows of spoilers are arranged parallel to the Y-axis direction. The spoiler at a position 4D away from the pile foundation body is defined as the first row, and the second row, the third row and the fourth row are arranged in sequence; In the second column, a spoiler is arranged at the intersection of the Y axis and the X axis; in the third column, a spoiler is arranged at each of the three quarter points of the line between the two spoilers located on the tangent along the Y axis direction.

6. The flow disturbance system for mitigating seabed scour and erosion around offshore wind turbine pile foundations according to claim 2, characterized in that: For the disturbance flow plates distributed along the circle n, the center of the semicircular arc corresponding to the central angle coincides with the circumference of the circle n.

7. The flow disturbance system for mitigating seabed scour and erosion around offshore wind turbine pile foundations according to claim 2, characterized in that: The spoilers located on circle 1 and circle 2 have 8 threaded holes on the fixing plate at the bottom, and the remaining spoilers have 4 threaded holes on the fixing plate at the bottom. The threaded holes are evenly distributed along the circumference of the fixing plate. A fixing screw is inserted into each threaded hole.

8. The construction method of the spoiler system for slowing down the scouring and erosion of the seabed around the pile foundation of an offshore wind turbine according to any one of claims 1 to 7, characterized in that: The specific steps are: Step S1, design the installation points of the spoiler on the concentric circles, take the pile foundation body as the center, design four concentric circles at positions of 0.5D, 1.0D, 1.5D and 2.0D away from the pile foundation body, respectively, and define them as circle 1, circle 2, circle 3 and circle 4, each concentric circle is provided with 12 points along the circumference, the two points on the X-axis in circle 1 are 1-1, the two points on the Y-axis are 1-4, the two points at 30° to the X-axis are 1-2, the two points at 60° to the X-axis are 1-3, the two points on the X-axis in circle 3 are The points are 3-1, the two points on the Y axis are 3-4, the two points at 30° to the X axis are 3-2, the two points at 60° to the X axis are 3-3, the four points at 15° to the X axis in circle 2 are 2-1, the four points at 15° to the Y axis are 2-3, the points 2-2 are evenly distributed between 2-1 and 2-3, the four points at 15° to the X axis in circle 4 are 4-1, the four points at 15° to the Y axis are 4-3, the points 4-2 are evenly distributed between 4-1 and 4-3, and D is the diameter of the pile foundation body; Step S2, design the installation point of the external part spoiler, design point 5-1 at two symmetrical points at a distance of 4D from the pile foundation body, the line connecting point 5-1 and point 4-2 is a tangent of circle 4, and points are respectively set at three quarter points of the tangent, starting from 5-1, 5-2, 5-3 and 5-4 are arranged in sequence, point 5-5 is arranged at the perpendicular intersection point of the line formed between the two points 5-2 and the X-axis, point 5-7 is arranged at the perpendicular intersection point of the line formed between the two points 5-3 and the X-axis, and the center position of the line formed by 5-3 and 5-7 is point 5-6; Step S3, install the fixing plate in the order of points 4-3, 4-2, 5-4, 5-3, 5-2, 5-1, 3-4, 3-3, 3-2, 4-1, 5-6, and 5-5, and vertically fix the spoiler on the fixing plate, so that the center angle of the concave surface of the spoiler arc is located on the circumference of circle 1 or circle 2 or circle 3 or circle 4; Step S4, continue to install the fixing plate in the order of points 2-3, 2-2, 2-1, 3-1, 1-4, 1-3, 1-2, and 1-1, vertically fix the spoiler on the fixing plate, and the center of the circle corresponding to the concave surface of the spoiler arc is located on the circumference of circle 1 or circle 2 or circle 3 or circle 4, completing the construction and installation of the spoiler system.

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