Device for suppressing vortex-induced vibration of offshore wind turbine cable caused by scouring

Abstract

The invention discloses a suppression device for vortex-induced vibration caused by scouring of an offshore wind turbine cable. The suppression device is arranged between a wind turbine tower drum and a J-shaped pipe. The device comprises a rack, a first vertical guide rail and a second vertical guide rail, the shell can slide along the guide rail; the elastic supporting mechanism is arranged in the shell and used for elastically supporting the J-shaped pipe; and a set of full-mechanical vibration sensing-transmission-execution mechanism. The mechanism can sense the vertical reciprocating motion, generated by vortex-induced vibration, of the J-shaped pipe, and the vibration is converted into acting force for intermittently locking or unlocking the stepping wheel, so that the whole device and the J-shaped pipe automatically and gradually descend. According to the device, vortex-induced vibration is suppressed by lowering the cable into the scouring pit, the device is located above the sea surface, the reliability is high, and the attributes of the cable are not changed.

Description

Technical Field

[0001] This invention relates to the field of marine engineering technology, and specifically to a device for suppressing vortex-induced vibration of offshore wind turbine cables caused by scouring. Background Technology

[0002] In marine engineering, when ocean currents flow around slender structures (such as submarine cables), they create alternating vortices on both downstream sides, forming what is known as a "Kármán vortex street." These periodically detaching vortices exert a reciprocating hydrodynamic load on the structure. When the frequency of this load approaches the structure's natural frequency, it triggers severe vibrations, known as "vortex-induced vibration." Vortex-induced vibration is one of the main causes of fatigue damage and even fracture in submarine cables, risers, and other structures.

[0003] For offshore wind turbines, the submarine cables are typically connected to the wind turbine tower via J-shaped conduits, such as... Figure 1 As shown, in the initial stage of wind turbine foundation installation, the span length and height of the submarine cable 32 are relatively small, making it less prone to vortex-induced vibration. However, over time, the seabed 35 surrounding the large-diameter pile foundation 33 of the wind turbine will be eroded by water currents, forming scour pits 34. This leads to a significant increase in the span length and height of the cable, and its natural frequency decreases accordingly, making it highly susceptible to vortex-induced vibration due to ocean currents. Figure 1 (D represents the direction of ocean current, and F represents the direction of hydrodynamics), which poses a serious threat to the safe operation of wind farms.

[0004] To address this issue, existing technologies mainly fall into two categories. The first category involves installing additional structures such as fairings and spoilers on the cable to alter its cross-sectional shape, thereby disrupting the formation of the Karman vortex street. The second category employs active dynamic structures, such as installing a rotatable column on the cable, to actively interfere with the flow field morphology near the cable.

[0005] However, the aforementioned existing technical solutions present significant technical challenges and drawbacks in practical engineering applications. First, regardless of whether the solution is active or passive, the suppression device must be directly installed on the underwater cable, constantly immersed in seawater with strong biological and chemical corrosive properties, and subjected to wave impacts. This places extremely high demands on the device's waterproof and corrosion-resistant design, as well as its long-term reliability and durability, resulting in high maintenance costs. Second, cable suspension sections at risk of vortex-induced vibration are typically long, often requiring multiple suppression devices to be installed along the cable segments, significantly increasing installation costs. Most importantly, any device attached to the cable alters its weight, bending stiffness, and hydrodynamic characteristics. This prevents designers from directly applying existing, mature design specifications and engineering experience for mechanical calculations. While solving the vortex-induced vibration problem, it introduces new uncertainties into the overall safety design of the cable. Summary of the Invention

[0006] The purpose of this invention is to provide a device for suppressing vortex-induced vibration of offshore wind turbine cables caused by scouring, so as to solve the problem of fatigue or even damage to submarine cables and other facilities caused by vortex-induced vibration.

[0007] To solve the above-mentioned technical problems, the present invention specifically provides the following technical solution:

[0008] A device for suppressing vortex-induced vibration of offshore wind turbine cables caused by scouring is installed between the wind turbine tower and the J-shaped pipe. The suppression device includes:

[0009] The first vertical guide rail is fixedly installed on the wind turbine tower;

[0010] The rack is fixed vertically on the wind turbine tower and located beside the first vertical guide rail;

[0011] The outer casing slides in conjunction with the first vertical guide rail, and a rack passes through a slot on the outer casing to allow the outer casing to move up and down along the rack;

[0012] The J-tube elastic support mechanism is located inside the housing and is used to elastically support the J-tube that runs vertically through the housing, and to allow the J-tube to move vertically relative to the housing.

[0013] The gear is fixedly connected to the housing and meshes with the rack. Under the gravity of the housing and the J-shaped tube, the gear always tends to mesh with the rack and rotate.

[0014] The stepping wheel has a fixed shaft connected to the housing and is mechanically connected to the gears. Several blades extending radially outward are formed on the outer periphery of the stepping wheel.

[0015] The first brake wheel and the second brake wheel are located on opposite sides of the stepper wheel's axial direction, and the axes of the first brake wheel and the second brake wheel are parallel to the axis of the stepper wheel.

[0016] The motion conversion mechanism is located inside the housing and has a force-applying end for connecting the first brake wheel and the second brake wheel. The motion conversion mechanism is used to convert the vertical reciprocating motion of the J-tube into the lateral reciprocating motion of the force-applying end.

[0017] In the reciprocating motion at the force application end, the first brake wheel and the second brake wheel alternately leave or enter between adjacent blades to release or lock the stepping wheel with a rotational tendency to rotate, so that the stepping wheel rotates two steps in a predetermined direction in one reciprocating motion cycle at the force application end, so that the housing and J-shaped tube descend as a whole.

[0018] Furthermore, the J-tube elastic support mechanism includes:

[0019] A fixed platform is horizontally fixed inside the housing, and a second through hole is formed on the fixed platform to avoid the J-shaped tube;

[0020] An annular flange is fixedly mounted on the outside of the J-shaped tube in a coaxial manner. The annular flange is located inside the outer shell and directly above the fixed platform.

[0021] The spring is coaxially sleeved on the outside of the J-shaped tube, with its upper and lower ends abutting against the annular flange and the fixed platform, respectively.

[0022] Furthermore, the suppression device also includes a reduction mechanism for amplifying the rotational torque of the stepper wheel and transmitting it to the gear, the reduction mechanism comprising:

[0023] The first transmission gear is coaxially connected to the stepper wheel;

[0024] The second transmission gear meshes with the first transmission gear, and the diameter of the second transmission gear is larger than the diameter of the first transmission gear.

[0025] The reducer is slidably mounted on the first vertical guide rail. The reducer is connected to the second transmission gear and the gear. The gear is connected to the low-speed end of the reducer, and the second transmission gear is connected to the high-speed end of the reducer.

[0026] Furthermore, the motion conversion mechanism includes:

[0027] Vibration guide frame, one end of which is fixedly connected to the outer wall of the J-shaped tube;

[0028] The vibration guide wheel is connected to the other end of the vibration guide frame;

[0029] The vibration sensor is mounted on the inner wall of the outer casing on the side away from the slot.

[0030] The vibration sensing plate has a V-shaped structure with a V-shaped groove. The middle bend is connected to the vibration sensing seat shaft. The guide wheel is housed in the V-shaped groove so that it contacts the groove wall when the guide wheel moves vertically, thereby driving the vibration sensing plate to rotate.

[0031] The commutation unit, located inside the housing, includes:

[0032] The input component is capable of reciprocating rotation around a fixed axis, and the rotation axis of the input component is coaxially and fixedly connected to the rotation axis of the vibration sensing plate.

[0033] The output component, i.e., the force-applying end, is capable of horizontal reciprocating movement along a fixed straight line; and

[0034] A linkage mechanism connects an input component and an output component, and is used to convert the rotational reciprocating motion of the input component into the horizontal reciprocating motion of the output component.

[0035] According to claim 5, a device for suppressing vortex-induced vibration of offshore wind turbine cables caused by scouring is characterized in that the commutation unit comprises:

[0036] The joystick is the input component;

[0037] A connecting rod is a linkage mechanism in which one end of the connecting rod is axially connected to the free end of the rocker arm.

[0038] The push rod is the output component, with one end of the push rod axially connected to the other end of the connecting rod;

[0039] A horizontal guide rail is fixedly installed on the inner wall of the housing, and the push rod is slidably connected to the horizontal guide rail.

[0040] Furthermore, the end of the push rod away from the connecting rod forms a V-shaped bracket for avoiding the shaft end of the stepper wheel, and the first brake wheel and the second brake wheel are respectively set at both ends of the V-shaped bracket.

[0041] Furthermore, the top and bottom walls of the outer casing each have a first through hole for the J-shaped tube to pass through. Each first through hole is provided with several guide wheels evenly distributed along the periphery of the J-shaped tube, and all guide wheels roll and fit against the outer wall of the J-shaped tube.

[0042] Furthermore, a reset torsion spring is provided at the shaft connection between the vibration sensing plate and the vibration sensing base to make the center surface of the V-groove of the vibration sensing plate tend to be horizontal.

[0043] Furthermore, the suppression device includes:

[0044] The damping rod is set in a longitudinal position, with the lower end of the damping sensor connected to the inner wall of the housing and the upper end connected to the vibration sensor base.

[0045] The second vertical guide rail is set on the inner wall of the housing, and the vibration sensing seat is slidably connected to the second vertical guide rail.

[0046] The beneficial effects of this invention are:

[0047] 1. The device of the present invention is installed on the wind turbine tower. Its core motion conversion mechanism, stepping wheel, gear and other precision components are all housed in the outer shell and do not come into direct contact with seawater. This fundamentally avoids problems such as seawater corrosion, biological attachment and wave impact, significantly improves the reliability of long-term operation and reduces maintenance costs.

[0048] 2. The device of the present invention uses a purely mechanical locking and releasing mechanism to convert the vertical motion of the J-tube caused by vortex-induced vibration into the power of the unidirectional rotation of the locking or unlocking stepping wheel. Finally, through the meshing of gears and racks, the J-tube is automatically and gradually lowered. This process reduces the hydrodynamic load on the cable on the one hand, and changes the natural frequency of the cable on the other hand. The two aspects work together to effectively suppress vortex-induced vibration.

[0049] 3. The device of the present invention acts on the J-shaped tube rather than the cable body, without changing the weight, stiffness and hydrodynamic characteristics of the cable, so that engineers can continue to use mature design specifications and experience, avoiding design uncertainties caused by the introduction of new components. Attached Figure Description

[0050] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0051] Figure 1 This is a schematic diagram illustrating the formation and working principle of vortex-induced vibration.

[0052] Figure 2 This is a schematic diagram showing the installation position of the suppression device of the present invention;

[0053] Figure 3 This is a three-dimensional structural diagram of the suppression device of the present invention. Figure 1 ;

[0054] Figure 4 This is a three-dimensional structural diagram of the suppression device of the present invention. Figure 2 ;

[0055] Figure 5 This is a schematic diagram of the principle of the J-type tube suppression device when stationary according to the present invention;

[0056] Figure 6 This is a schematic diagram of the principle of the J-type tube rising suppression device of the present invention;

[0057] Figure 7 This is a schematic diagram of the principle of the J-type tube descent suppression device of the present invention;

[0058] The labels in the diagram represent the following: 1-Wind turbine tower; 2-J-shaped tube; 3-First vertical guide rail; 4-Rack; 5-Outer shell; 6-Slot; 7-Vibration guide frame; 8-Vibration guide wheel; 9-Vibration sensor seat; 10-Vibration sensor plate; 11-Gear; 12-Stepping wheel; 13-Blade; 14-First brake wheel; 15-Second brake wheel; 16-Sloping section; 17-Fixed platform; 18-Annular flange; 19-Spring; 20-First transmission. 21-Second transmission gear; 22-Reducer; 23-Rock arm; 24-Connecting rod; 25-Push rod; 26-Horizontal guide rail; 27-V-shaped bracket; 28-First through hole; 29-Guide wheel; 30-Damping rod; 31-Second vertical guide rail; 32-Submarine cable; 33-Large diameter pile foundation; 34-Scrubber pit; 35-Seabed; 36-Suppression device; 37-Slider; 38-Reset torsion spring; 39-Second through hole. Detailed Implementation

[0059] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0060] Reference Figures 2 to 7 As shown, this invention provides a device for suppressing vortex-induced vibration of offshore wind turbine cables caused by scouring. The device is installed between the wind turbine tower 1 and the J-shaped pipe 2. Its core function is to automatically and progressively lower the overall height of the J-shaped pipe 2 when it senses vertical high-frequency vibration transmitted to the J-shaped pipe 2 by the submarine cable due to vortex-induced vibration, thereby lowering the cable into the seabed scouring pit and suppressing the vibration.

[0061] In a basic embodiment, a device for suppressing vortex-induced vibration of offshore wind turbine cables caused by scouring is disposed between the wind turbine tower 1 and the J-shaped tube 2. The device includes: a first vertical guide rail 3, fixedly disposed on the wind turbine tower 1; a rack 4, vertically fixedly disposed on the wind turbine tower 1 and located beside the first vertical guide rail 3; a housing 5, slidably engaged with the first vertical guide rail 3, the rack 4 passing through a slot 6 on the housing 5 to allow the housing 5 to move up and down along the rack 4; a J-shaped tube elastic support mechanism disposed within the housing 5 for elastically supporting the J-shaped tube 2 vertically passing through the housing 5 and allowing the J-shaped tube 2 to move vertically relative to the housing 5; a gear 11, fixedly abutted within the housing 5 and meshing with the rack 4; and a stepping wheel 12, fixedly abutted within the housing 5 and mechanically connected to the gear 11, the outer periphery of the stepping wheel 12 having a plurality of radially outwardly extending blades 13, the number of blades 13 preferably being odd. The first brake wheel 14 and the second brake wheel 15 are located on opposite sides of the stepper wheel 12, and their axes are parallel to the axis of the stepper wheel 12. A motion conversion mechanism is located inside the housing 5 and has a force-applying end for connecting the first brake wheel 14 and the second brake wheel 15. The motion conversion mechanism is used to convert the vertical reciprocating motion of the J-shaped tube 2 into the lateral reciprocating motion of the force-applying end. During the reciprocating motion of the force-applying end, the first brake wheel 14 and the second brake wheel 15 alternately enter between adjacent blades 13 to release the stepper wheel 12, which has a rotational tendency, so that the stepper wheel 12 rotates two steps in a predetermined direction in one reciprocating motion cycle of the force-applying end, so that the housing 5 and the J-shaped tube 2 descend as a whole.

[0062] Its working principle constitutes an escapement mechanism. The core is that the weight of the entire device generates a continuous driving torque through the gear 11 meshing with the rack 4, causing the stepping wheel 12 to rotate. The first brake wheel 14 and the second brake wheel 15 act as locking pins. When stationary, one brake wheel is always positioned between the blades 13, locking the stepping wheel 12 and preventing its rotation. When the J-tube 2 vibrates upwards, one brake wheel (such as 14) is pulled out of the blade gap, unlocking the stepping wheel 12, causing it to instantly rotate one step under the driving torque, until it is locked again by another brake wheel (such as 15) that subsequently enters the gap; the process is reversed when the J-tube 2 descends. Thus, one complete vibration of the J-tube 2 releases the stepping wheel 12, causing it to rotate two steps. The effect of this design is that the locking pin will only repeatedly open and close when continuous vibration occurs, allowing the device to descend gradually and stably.

[0063] To enhance the bending resistance of the blades 13 of the stepper wheel 12, a beveled portion 16 is formed at the root of the blades 13, thereby increasing the bending resistance of the blades 13.

[0064] A specific implementation of the J-tube elastic support mechanism may include: a fixed platform 17, horizontally fixed inside the housing 5, with a second through hole 39 formed on the fixed platform 17 to avoid the J-tube 2; an annular flange 18, coaxially fixed on the outside of the J-tube 2, located inside the housing 5 and directly above the fixed platform 17; and a spring 19, coaxially sleeved on the outside of the J-tube 2, with its upper and lower ends respectively abutting against the annular flange 18 and the fixed platform 17. Its working principle is to utilize the elastic deformation of the spring 19 to respond to force changes on the J-tube 2. When vortex-induced vibration generates additional dynamic loads, the spring 19 compresses and elongates, thereby converting the force signal into a displacement signal of the J-tube 2 relative to the housing 5. This design is simple and can reliably achieve preliminary sensing of vibration signals.

[0065] In a preferred embodiment, the motion conversion mechanism may specifically include: a vibration guide frame 7, one end of which is fixedly connected to the outer wall of the J-shaped tube 2; a vibration guide wheel 8, which is axially connected to the other end of the vibration guide frame 7; a vibration sensing seat 9, which is disposed on the inner wall of the outer shell 5 away from the slot 6; a vibration sensing plate 10, which has a V-shaped structure and is provided with a V-shaped groove, the middle of which is axially connected to the vibration sensing seat 9, the vibration guide wheel 8 being accommodated in the V-shaped groove so that it contacts the groove wall of the V-shaped groove when the vibration guide wheel 8 moves vertically, thereby driving the vibration sensing plate 10 to rotate; and a reversing unit. The reversing unit includes an input component capable of rotating about a fixed axis, the rotation axis of which is coaxially fixedly connected to the rotation axis of the vibration sensing plate 10; an output component capable of horizontally reciprocating along a fixed straight line, which is the force application end; and a linkage mechanism connecting the input component and the output component. Its working principle is as follows: the guide wheel 8 moves up and down within the V-groove of the vibration sensing plate 10, efficiently converting the vertical linear motion of the J-tube 2 into the angular oscillation of the vibration sensing plate 10. The subsequent reversing unit further converts this angular oscillation into the horizontal linear motion of the force-applying end (output component). The effect of this design is to achieve a reliable motion conversion from vertical to horizontal linear motion, providing precise input for the subsequent escapement mechanism.

[0066] To enable the vibration sensing plate 10 to automatically return to its ready state when no force is applied, a reset torsion spring 38 can be installed at the shaft connection between the vibration sensing plate 10 and the vibration sensing base 9 to make the center surface of the V-groove of the vibration sensing plate 10 tend to be horizontal. Its working principle is to utilize the elastic potential energy stored in the torsion spring 38 to drive the vibration sensing plate 10 back to its initial horizontal equilibrium position after the external force from the guide wheel 8 disappears. This design ensures that the device automatically resets after each vibration or in a static state, preparing for the next vibration response, thus improving the device's response sensitivity and reliability. Furthermore, when the vibration sensing plate 10 is in its initial horizontal equilibrium position, the first brake wheel 14 and the second brake wheel 15 are located within the adjacent blades 13 at both ends of the stepper wheel 12 in the radial direction, respectively, at which point the first brake wheel 14 and the second brake wheel 15 jointly lock the stepper wheel 12.

[0067] Furthermore, the aforementioned reversing unit can employ a crank-slider mechanism, specifically comprising: a rocker arm 23, which is the input component; a connecting rod 24, which is a linkage mechanism, with one end of the connecting rod 24 axially connected to the free end of the rocker arm 23; a push rod 25, which is the output component, with one end of the push rod 25 axially connected to the other end of the connecting rod 24; and a horizontal guide rail 26, fixedly mounted on the inner wall of the housing 5, with the push rod 25 slidably connected to the horizontal guide rail 26. This mechanism can precisely convert the swing of the rocker arm 23 into the linear reciprocating motion of the push rod 25, representing a mature and reliable transmission method. As another parallel implementation, the reversing unit can also employ a Scottish yoke mechanism, which similarly achieves stable conversion of the rocker arm's swing into the linear reciprocating motion of the push rod. To facilitate the arrangement of the first brake wheel 14 and the second brake wheel 15, the end of the push rod 25 away from the connecting rod 24 can form a V-shaped bracket 27 to avoid the shaft end of the stepper wheel 12. The first brake wheel 14 and the second brake wheel 15 are respectively set at both ends of the V-shaped bracket 27. The design of the V-shaped bracket 27 cleverly solves the space problem of arranging two brake wheels at the end of the push rod 25.

[0068] To increase the driving torque and ensure a smooth descent of the device, a reduction mechanism can be installed between the stepper wheel 12 and the gear 11. This reduction mechanism may include: a first transmission gear 20, coaxially connected to the stepper wheel 12; a second transmission gear 21, meshing with the first transmission gear 20, and having a diameter larger than that of the first transmission gear 20; and a reducer 22, slidably mounted on the first vertical guide rail 3, connecting the second transmission gear 21 and the gear 11. The gear 11 is connected to the low-speed end of the reducer 22, and the second transmission gear 21 is connected to the high-speed end of the reducer 22. Its working principle is to achieve speed reduction and torque increase through gear transmission and the reducer. The small, rapid rotation output by the stepper wheel 12 prevents excessive height adjustment.

[0069] After passing through this mechanism, the torque is converted into slow but high-torque rotation, which is ultimately transmitted to the gear 11 that meshes with the rack 4. The effect of this design is to ensure that the device has sufficient force to overcome its own weight and various frictional resistances, achieving a smooth and controllable descent.

[0070] At the same time, this design minimizes the torque load on the stepper wheel 12, thereby reducing the difficulty in strength and size design and allowing the mechanism to be designed to be more compact.

[0071] To prevent the device from misresponding to low-frequency or monotonous load changes such as tidal fluctuations, a filtering mechanism can be introduced. This mechanism may include: a damping rod 30, arranged longitudinally, with its lower end connected to the inner wall of the housing 5 and its upper end connected to the vibration sensing base 9; and a second vertical guide rail 31, disposed on the inner wall of the housing 5, with the vibration sensing base 9 slidably connected to the second vertical guide rail 31. Its working principle is similar to a mechanical high-pass filter: for high-frequency vortex-induced vibrations, the damping rod 30, due to its slow response speed, cannot extend or retract in time, the vibration sensing base 9 remains approximately fixed, and the device responds normally; however, for slow load changes, the vibration sensing base 9, under continuous unidirectional pressure, will drive the damping rod 30 to move slowly, thereby restoring the vibration sensing plate 10 to equilibrium, avoiding false triggering and non-triggering caused by continuous and stable load changes. The effect of this design is to significantly improve the device's signal recognition capability, enabling it to respond only to the target vortex-induced vibration signal.

[0072] To ensure the overall stability of the device's operation, first through holes 28 for the J-shaped tube 2 to pass through can be provided on both the top and bottom walls of the outer casing 5. Each first through hole 28 contains several guide wheels 29 evenly distributed along the circumference of the J-shaped tube 2, all of which roll against the outer wall of the J-shaped tube 2. The working principle is to replace sliding friction with rolling friction, greatly reducing the motion resistance between the J-shaped tube 2 and the outer casing 5. This design ensures that the J-shaped tube 2 can respond sensitively to vibrations, improving the overall sensing accuracy of the device.

[0073] The above embodiments are merely exemplary embodiments of the present invention and are not intended to limit the present invention. The scope of protection of the present invention is defined by the claims. Those skilled in the art can make various modifications or equivalent substitutions to the present invention within its spirit and scope of protection, and such modifications or equivalent substitutions should also be considered as falling within the scope of protection of the embodiments of the present invention.

Claims

1. A device for suppressing vortex-induced vibration of offshore wind turbine cables caused by scouring, disposed between the wind turbine tower (1) and the J-shaped pipe (2), characterized in that, The suppression device includes: The first vertical guide rail (3) is fixedly installed on the wind turbine tower (1); The rack (4) is fixedly mounted vertically on the wind turbine tower (1) and is located beside the first vertical guide rail (3); The outer shell (5) is slidably engaged with the first vertical guide rail (3), and the rack (4) passes through a slot (6) on the outer shell (5) to allow the outer shell (5) to move up and down along the rack (4); The J-shaped tube elastic support mechanism is disposed inside the outer shell (5) to elastically support the J-shaped tube (2) that is vertically penetrating the outer shell (5) and to allow the J-shaped tube (2) to generate vertical relative movement with respect to the outer shell (5); The gear (11) is fixedly connected to the housing (5) and meshes with the rack (4). Under the gravity of the housing (5) and the J-shaped tube (2), the gear (11) always has the tendency to mesh with the rack (4) and rotate. The stepping wheel (12) is fixedly connected to the housing (5) and mechanically connected to the gear (11). The outer periphery of the stepping wheel (12) has a number of blades (13) extending radially outward. The first brake wheel (14) and the second brake wheel (15) are located on opposite sides of the axial direction of the stepper wheel (12), and the axes of the first brake wheel (14) and the second brake wheel (15) are parallel to the axis of the stepper wheel (12). The motion conversion mechanism is located inside the housing (5) and has a force-applying end for connecting the first brake wheel (14) and the second brake wheel (15). The motion conversion mechanism is used to convert the vertical reciprocating motion of the J-tube (2) into the lateral reciprocating motion of the force-applying end. In the reciprocating motion of the force-applying end, the first brake wheel (14) and the second brake wheel (15) alternately leave or enter between adjacent blades (13) to release or lock the stepping wheel (12) with a rotational tendency to rotate, so that the stepping wheel (12) rotates two steps in a predetermined direction in one reciprocating motion cycle of the force-applying end, so that the housing (5) and the J-shaped tube (2) descend as a whole.

2. The device for suppressing vortex-induced vibration of offshore wind turbine cables induced by scouring, as described in claim 1, is characterized in that... The J-shaped tube elastic support mechanism includes: The fixed platform (17) is fixedly installed in the outer shell (5) in a horizontal state, and a second through hole (39) is formed on the fixed platform (17) to avoid the J-shaped tube (2). An annular flange (18) is fixedly disposed on the outside of the J-shaped tube (2) in a coaxial state. The annular flange (18) is located inside the outer shell (5) and directly above the fixed platform (17). A spring (19) is coaxially sleeved on the outside of the J-shaped tube (2), and the upper and lower ends of the spring (19) abut against the annular flange (18) and the fixed platform (17) respectively.

3. The device for suppressing vortex-induced vibration of offshore wind turbine cables induced by scouring, as described in claim 1, is characterized in that... The suppression device further includes a reduction mechanism for amplifying the rotational torque of the stepper wheel (12) and transmitting it to the gear (11), the reduction mechanism comprising: The first transmission gear (20) is coaxially connected to the stepper wheel (12); The second transmission gear (21) meshes with the first transmission gear (20), and the diameter of the second transmission gear (21) is larger than the diameter of the first transmission gear (20). The reducer (22) is slidably mounted on the first vertical guide rail (3). The reducer (22) is connected to the second transmission gear (21) and the gear (11). The gear (11) is connected to the low-speed end of the reducer (22), and the second transmission gear (21) is connected to the high-speed end of the reducer (22).

4. The device for suppressing vortex-induced vibration of offshore wind turbine cables induced by scouring, as described in claim 1, is characterized in that... The motion conversion mechanism includes: Vibration guide frame (7), one end of which is fixedly connected to the outer wall of the J-shaped tube (2); The vibration guide wheel (8) is connected to the other end of the vibration guide frame (7); Vibration sensing base (9) is disposed on the inner wall of the outer shell (5) on the side away from the slot (6); The vibration sensing plate (10) has a V-shaped structure and a V-shaped groove. The middle turning point is axially connected to the vibration sensing seat (9). The guide wheel (8) is accommodated in the V-shaped groove so that it contacts the groove wall of the V-shaped groove when the guide wheel (8) moves vertically, thereby driving the vibration sensing plate (10) to rotate. The commutation unit, located within the housing (5), includes: The input component is capable of reciprocating rotation around a fixed axis, and the rotation axis of the input component is coaxially and fixedly connected to the rotation axis of the vibration sensing plate (10). The output component, i.e., the force-applying end, is capable of horizontal reciprocating movement along a fixed straight line; and A linkage mechanism connects the input component and the output component, and is used to convert the rotational reciprocating motion of the input component into the horizontal reciprocating motion of the output component.

5. The device for suppressing vortex-induced vibration of offshore wind turbine cables induced by scouring, as described in claim 4, is characterized in that... The commutation unit includes: The joystick (23) is the input component; Link (24), which is the linkage mechanism, has one end axially connected to the free end of the rocker arm (23); The push rod (25) is the output component, and one end of the push rod (25) is axially connected to the other end of the connecting rod (24); A horizontal guide rail (26) is fixedly installed on the inner wall of the outer shell (5), and the push rod (25) is slidably connected to the horizontal guide rail (26).

6. The device for suppressing vortex-induced vibration of offshore wind turbine cables induced by scouring, as described in claim 5, is characterized in that... The push rod (25) has a V-shaped bracket (27) at the end away from the connecting rod (24) to avoid the shaft end of the stepper wheel (12). The first brake wheel (14) and the second brake wheel (15) are respectively disposed at both ends of the V-shaped bracket (27).

7. The device for suppressing vortex-induced vibration of offshore wind turbine cables induced by scouring, as described in claim 1, is characterized in that... The top and bottom walls of the outer casing (5) each have a first through hole (28) for the J-shaped tube (2) to pass through. Each first through hole (28) is provided with a number of guide wheels (29) evenly distributed along the periphery of the J-shaped tube (2). All the guide wheels (29) roll and fit against the outer wall of the J-shaped tube (2).

8. The device for suppressing vortex-induced vibration of offshore wind turbine cables induced by scouring, as described in claim 4, is characterized in that... A reset torsion spring (38) is provided at the shaft connection between the vibration sensing plate (10) and the vibration sensing seat (9) to make the center surface of the V-groove of the vibration sensing plate (10) tend to be horizontal.

9. The device for suppressing vortex-induced vibration of offshore wind turbine cables induced by scouring, as described in claim 4, is characterized in that... The suppression device includes: The damping rod (30) is arranged in a longitudinal state. The lower end of the damping rod is connected to the inner wall of the outer shell (5), and the upper end is connected to the vibration sensing seat (9). The second vertical guide rail (31) is disposed on the inner wall of the outer shell (5), and the vibration sensing seat (9) is slidably connected to the second vertical guide rail (31).

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