Artificial fish reef suitable for weak-flow sea area and capable of being freely combined and arrangement method of artificial fish reef

Abstract

The invention relates to the technical field of ocean engineering, in particular to an artificial fish reef suitable for a weak-flow sea area and capable of being freely combined and an arrangement method of the artificial fish reef. The artificial fish reef is of a square frame structure with the hollow interior and six open faces, and any two of the multiple frame structures can be meshed with each other in a three-dimensional space. Flow guide plates with different spatial orientations can be selectively arranged in the frame body, so that the frame body can be divided into five types which can generate upward flow, downward flow, horizontal accelerated flow and no flow guide. Through modular combination of different types of units, an artificial fish reef cluster with single or composite flow field effects such as upward flow, downward flow or horizontal accelerated flow can be constructed. The arrangement method comprises the steps of obtaining sea area environment and flow field data, determining a putting area based on numerical simulation, optimizing a reef cluster combination scheme, and finally implementing putting and monitoring. According to the invention, a controllable combined flow field of upward flow, downward flow, horizontal accelerated flow and back vortex can be generated in a preset area.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of ocean engineering, and particularly relates to a freely combinable artificial fish reef suitable for weak current sea areas and a layout method thereof. BACKGROUND

[0002] With the deepening of the construction of the marine ranching, as the core carrier for realizing the proliferation of fishery resources, ecological restoration and habitat construction, the application scale and technical requirements of the artificial fish reef are continuously improved. The artificial fish reef mainly promotes the vertical exchange of nutrients, the attachment and aggregation of bait organisms and the hiding and inhabiting of swimming organisms through the synergistic effect of flow field effect, biological effect and enemy avoidance effect. Among them, the flow field effect is particularly key, which relies on the guiding, separating and shielding effect of the reef structure on the water flow, forming upwelling on the flow surface, downwelling and vortex flow in the back flow area, so as to build a hydrodynamic microenvironment conducive to the proliferation of marine organisms. In order to strengthen such effects, the existing fish reef shapes have developed into various structures such as box type, tower type and frame type, and tend to be large-scale and complex design.

[0003] However, the current combined artificial fish reef can expand the flow area by stacking multiple bodies, but it has significant defects in actual layout: on the one hand, the structure is too complex, causing mutual interference of the flow field after combination, making it difficult to accurately control the spatial distribution and intensity of the upwelling, downwelling and horizontal flow; on the other hand, in the weak current sea area where the flow velocity is generally lower than 0.1 m / s, the traditional fish reef lacks an effective flow guiding mechanism, making it difficult to generate enough upwelling to drive the upwelling of bottom nutrients, and the weak water flow has limited scouring ability on the seabed, restricting the play of ecological function; in addition, the existing deployment method relies on experience layout, lacks quantitative flow field prediction means based on regional tidal current characteristics and fish reef combination parameters, resulting in high uncertainty of the actual flow field effect of the fish reef group, making it difficult to customize the hydrodynamic environment with specific functions. SUMMARY

[0004] In view of the deficiencies in the prior art, the present application provides a freely combinable artificial fish reef suitable for weak current sea areas and a layout method thereof, which has a simple structure, can be freely combined and is suitable for weak current conditions, can accurately generate a controllable combined flow field of upwelling, downwelling, horizontal accelerated flow and back vortex flow in a preset area, and thus improves the ecological restoration efficiency and fishery proliferation certainty of the artificial fish reef in different sea environments.

[0005] In order to achieve the above technical effects, the present application provides a freely combinable artificial fish reef suitable for weak current sea areas, which is a square frame structure with a hollow interior and six open sides. Three adjacent sides of the square frame structure are provided with interlocking interfaces configured to allow any two of the multiple frames to engage with each other in three-dimensional space and be fixed by detachable fasteners, thereby forming an overall fish reef structure. The square frame structure is internally provided with or not provided with a flow guide plate, thereby forming five types of units: a first type of frame: the flow guide plate is arranged on the top of the frame and extends from the first side of the top of the frame to the side of the bottom of the frame in a diagonal direction, thereby forming a first inclined direction for generating an upward flow; a second type of frame: the flow guide plate is arranged on the top of the frame, which is arranged in mirror symmetry with the first type of unit, for generating a downward flow; a third type of frame: the flow guide plate is arranged on the side of the frame and extends horizontally from the first side of the side of the frame to the side of the frame in a diagonal direction, thereby forming a horizontal inclined direction for guiding and accelerating horizontal water flow; a fourth type of frame: the flow guide plate is arranged on the side of the frame, which is arranged in mirror symmetry with the third type of unit, for guiding and accelerating horizontal water flow; and a fifth type of frame: no flow guide plate is arranged.

[0006] As a preferred technical solution, the interlocking interface comprises a protruding structure arranged in the center of the side of the square frame structure and a recessed structure located on the opposite side, and the protruding structure and the recessed structure are both four-square frames capable of being connected by biting.

[0007] As a preferred technical solution, the application discloses a layout method of the above-mentioned artificial fish reefs which can be freely combined in weak-flow sea areas, comprising the following steps: S1: obtaining the coastline, topography and geological data of the intended placement area; S2: calculating the ebb and flow field process of the placement area based on a large-scale flow field numerical model; S3: determining the artificial fish reef placement area in combination with the geological conditions and the ebb and flow field; S4: calculating the upward flow, downward flow and horizontal accelerated flow under different artificial fish reef stacking layers and arrangement spacing based on a small-scale flow field numerical model; S5: determining the combination mode of the artificial fish reefs in combination with the functional needs of the artificial fish reefs; S6: completing the placement and installation of the actual sea area fish reef group.

[0008] As a preferred technical solution, the first combination mode in S5 is: stacking N columns of the first type of frame with increasing height along the water flow direction to form a first type of fish reef group with the same flow guide surface and capable of forming upward flow, wherein N is a natural number greater than 1; or, the flow surface uses the first type of frame vertically stacked, and N-1 columns of the fifth type of frame are arranged on the inner side thereof; mirroring and stacking N columns of the second type of frame with decreasing height on the back flow side of the first type of fish reef group without spacing, thereby forming a second type of fish reef group with upward flow on both sides; arranging a certain spacing between the first type of fish reef group and the mirrored fish reef group, thereby forming a third type of fish reef group.

[0009] As a preferred technical solution, the second combination mode in S5 is: stacking N columns of the second type of frame with decreasing height to form a fourth type of fish reef group with the same inclined surface and capable of forming downward flow, and arranging the fifth type of frame on the bottom layer, wherein N is a natural number greater than 1. The fourth type of artificial reef group consists of N columns of first-class frames with no gaps on the back side and mirror images of each other, with the height of each column increasing progressively. These columns form the fifth type of artificial reef group with descending currents on both sides.

[0010] As a preferred technical solution, the third combination method in S5 is to arrange artificial reef units vertically and at intervals. Adjacent artificial reef units are respectively composed of horizontally symmetrical third and fourth type frames superimposed, and a funnel mouth is formed at the axis of symmetry, which gradually narrows from the upstream side to the downstream side. A horizontal acceleration flow zone is formed inside the funnel mouth. The same artificial reef unit has the same guiding surface, and all artificial reef units together form the sixth type of artificial reef group.

[0011] As a preferred technical solution, a frame without a baffle is arranged on the left and right sides of the third or fourth type of frame.

[0012] As a preferred technical solution, the fourth combination of the artificial reefs is: setting up a first-class artificial reef group at a specific distance from the funnel-shaped outlet of the sixth-class artificial reef group to form a seventh-class artificial reef group that generates upwelling and horizontal acceleration flow. As a preferred technical solution, the fifth combination of artificial reefs is as follows: a fourth type of artificial reef group is placed at a specific distance from the inlet of the funnel mouth of the sixth type of artificial reef group, and a first type of artificial reef group is set at a specific distance from the outlet of the funnel mouth, forming an eighth type of artificial reef group with upflow, downflow and horizontal acceleration flow. As a preferred technical solution, the sixth combination of artificial reefs is to arrange the seventh type of artificial reef group on the upstream and downstream sides of the large aquaculture platform.

[0013] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention provides a simple, freely combinable artificial reef frame and its arrangement method, which can accurately generate a controllable combination of upwelling, downwelling, horizontal acceleration, and back vortex flow under weak current conditions. This solves the problems of mutual interference and uncertain ecological function of traditional artificial reef flow fields, realizes the quantitative control of flow field effects, and improves the effectiveness and applicability of artificial reefs in fishery enhancement and ecological restoration. Attached Figure Description

[0014] Figure 1 These are schematic diagrams of the first to fifth types of frames in this invention; Figure 2 This is a schematic diagram of the structure of the first type of artificial reef system in this invention; Figure 3 This is a schematic diagram of the structure of the second type of artificial reef system in this invention; Figure 4 This is a schematic diagram of the structure of the third type of artificial reef system in this invention; Figure 5 This is a schematic diagram of the structure of the fourth type of artificial reef system in this invention; Figure 6 This is a schematic diagram of the structure of the fifth type of artificial reef system in this invention; Figure 7 This is a schematic diagram of the sixth type of artificial reef system in this invention; Figure 8 This is a schematic diagram of the structure of the seventh type of artificial reef system in this invention; Figure 9 This is a schematic diagram of the eighth type of artificial reef system in this invention; Figure 10 This is a schematic diagram of the structure combining the artificial reef system and the aquaculture platform in this invention.

[0015] 1. First type of frame; 1-1. Square frame structure; 1-2. Protruding structure; 1-3. Recessed structure; 1-4. Fixing hole; 1-5. Flow guide plate; 2. Second type of frame; 3. Third type of frame; 4. Fourth type of frame; 5. Fifth type of frame; 6. First type of artificial reef group; 7. Second type of artificial reef group; 8. Third type of artificial reef group; 9. Fourth type of artificial reef group; 10. Fifth type of artificial reef group; 11. Sixth type of artificial reef group; 12. Seventh type of artificial reef group; 13. Eighth type of artificial reef group; 14. Aquaculture platform. Detailed Implementation

[0016] To facilitate understanding of the present invention, a more comprehensive description will be provided below, along with preferred embodiments. However, it should be understood that these embodiments are merely for more detailed explanation and should not be construed as limiting the invention in any way, i.e., not intended to limit the scope of protection of the invention.

[0017] Unless otherwise defined, the technical terms used in the following embodiments have the same meanings as commonly understood by those skilled in the art to which this invention pertains. Unless otherwise specified, the experimental reagents used in the following embodiments are conventional biochemical reagents; and the experimental methods described are conventional methods.

[0018] Example 1 like Figure 1 As shown, this embodiment discloses an artificial reef suitable for weak current sea areas that can be freely combined. It is a square frame structure 1-1 with a hollow interior and six open sides. The three adjacent sides of the square frame structure 1-1 are provided with interlocking interfaces. The interlocking interfaces are configured to allow any two of the multiple frames to interlock with each other in three-dimensional space and be fixed by detachable fasteners, thereby forming an overall artificial reef structure. The square frame structure has protruding structures 1-2 arranged in the center on three adjacent sides. The opposite side of the protruding structure has a recessed structure 1-3 that can be inserted and matched with it. Both the protruding structure and the recessed structure are square frames. The height of the protruding structure is slightly less than the depth of the recessed structure, and the width of the protruding structure is slightly less than the width of the recessed structure, so as to ensure automatic interlocking between multiple frames.

[0019] In some specific embodiments, the interlocking interface comprises a protruding structure arranged centrally on the side of the square frame structure, and a recessed structure on the opposite side, both of which are four-square frames that can be connected by biting.

[0020] In some specific embodiments, the protruding structure and the recessed structure are provided with fixing holes 1-4 at corresponding positions, and the detachable fastener is a bolt that can be inserted into the fixing holes 1-4, used to increase the structural stability in the stacking direction. Multiple fixing holes are provided according to the overall size of the four-square frame, ensuring the structural reliability under different numbers of layers and spacings.

[0021] In some specific embodiments, a deflector 1-5 can be arranged between the two adjacent sides of the frame of the protruding structure; the frame defines the deflection direction through the spatial orientation of its deflector 1-5, thereby constructing multiple types with different functions, including: a first type of frame 1 for generating upward flow, a second type of frame 2 for generating downward flow and being mirror-symmetric to the first type of frame, and a third type of frame 3 for generating horizontal accelerated flow; a fourth type of frame 4 is formed by removing the deflector to form a larger hollow volume according to functional needs; the deflector of the first type of frame 1 extends from the top first side of the frame to the bottom side of the frame in a diagonal direction, forming a first inclined direction, for guiding the oncoming water flow to the upper oblique side to generate upward flow; the second type of frame 2 is arranged in mirror symmetry with the first type of frame 1 to form a second inclined direction, for guiding the oncoming water flow to the lower oblique side to generate downward flow; the deflector of the third type of frame 3 extends horizontally from the first side of the frame to the side of the frame in a diagonal direction, forming a third inclined direction, for guiding and accelerating the water flow in the horizontal direction; the fourth type of frame 4 is arranged in mirror symmetry with the third type of frame 3, also for guiding and accelerating the water flow in the horizontal direction; the fifth type of frame 5 is not provided with a deflector to obtain a larger hollow volume. By using the first type of frame 1 to the fifth type of frame 5, an artificial reef group that can adapt to bidirectional reciprocating tidal flow can be constructed, ensuring that the preset flow field effect can be maintained when the direction of the tidal flow changes.

[0022] Embodiment 2 The present application also discloses a method for arranging the artificial reef, comprising the following specific steps: Step 1: Obtain the coastline, topography and geological data of the area where the artificial reef is to be put into; Step 2: Calculate the rising and falling tide flow field process in the put-in area based on a large-scale flow field numerical model; Step 3: Determine the artificial reef put-in area in combination with the geological conditions and the size of the rising and falling tide flow field; Step 4: Calculate the upward flow, downward flow and horizontal accelerated flow under different artificial reef stacking layers and arrangement spacings based on a small-scale flow field numerical model; Step 5: Determine the combination of artificial reefs according to the functional needs of artificial reefs; Step 6: Complete the actual sea area reef group deployment and installation.

[0023] In some specific embodiments, the shoreline data obtained in step 1 includes the historical seawater submerged to the farthest position of the land domain rear boundary coordinates, the terrain data is uniformly processed using the national 85 elevation datum, the water depth range covers the deepest part of the engineering area -20 meters ~ the highest part of the seawater submerged land 5 meters, and the geological data includes bottom type and particle size analysis, wherein the bottom is mainly silty sand with an average median particle size of 0.08 millimeters.

[0024] In some specific embodiments, in step 2, large-scale ocean numerical models such as Mike, Delft3D, FVCOM, ROMS, etc. use global tidal harmonic constants as open boundary conditions to simulate the tidal and tidal current processes in the sea area, and calculate the water level and flow field changes during the rise and fall of the tide in the engineering bay. The analysis results show that the bay where the artificial reefs are to be placed is mainly reciprocating flow, with the flow direction from the bay mouth to the bay bottom during the rising tide, and the flow direction is reversed during the falling tide. The overall flow velocity in the bay is between 0.1~0.5m / s, and the maximum flow velocity is located at the bay mouth, and the flow velocity in the bay is generally below 0.1m / s.

[0025] In some specific embodiments, in step 3, the deployment area is selected in combination with the geological conditions of the bay and the tidal current intensity in the bay, and the specific conditions include bottom material of silty sand, rising and falling tide velocity less than 0.1 meters per second, and water depth between -20 meters and -10 meters. The artificial reef combination forms a horizontal accelerating flow, a bottom upwelling flow, and a surface downwelling flow to improve the productivity of the sea area and build biological habitat space.

[0026] In some specific embodiments, in step 4, the numerical model includes Fluent, OpenFoam, FLOW3D, REEF3D, etc.; the small-scale flow field numerical model sets the size of a single artificial reef to 3 meters, the length and width are consistent, the slope of the deflector is 1:1, and the horizontal flow velocity in the sea area is set to 0.1 meters per second.

[0027] In some specific embodiments, in step 4, when creating upwelling, two first-type frame bodies 1 are arranged, with a total height of 6 meters. Simulation shows that the bottom water flows to the surface through the deflector to form an upwelling area, with a maximum upwelling velocity of 0.06 meters per second, which is about 60% of the background flow velocity, and a slow flow and turbulent flow area is generated behind the reef.

[0028] In some specific embodiments, the three-layer frame body arranged in step 4 for creating a descending flow includes the second type of frame body 2 in the upper two layers and the fifth type of frame body 5 in the bottom layer, with a total height of 9 meters, simulating the process of the surface water flowing to the bottom layer through the guide plate to form a descending flow, with a maximum descending flow rate of 0.05 meters per second, promoting the mixing of the oxygen-rich surface layer and the oxygen-poor bottom layer.

[0029] In some specific embodiments, the two groups of artificial reefs composed of the third type of frame body 3 and the fourth type of frame body 4 are arranged in step 4 for creating a horizontal accelerating flow. Each group is vertically arranged in two layers and horizontally arranged in four blocks, with a minimum distance of 5 meters between the two groups, a length of 12 meters, and a height of 6 meters. This simulates the process of beam flow of the horizontal guide plate to form an accelerating flow, with a maximum accelerating flow of 0.15 meters per second, which is an increase of 50% compared to the background flow rate.

[0030] In some specific embodiments, the superimposed effect of horizontal accelerating flow and upwelling is created by arranging the artificial reef group 6 behind the artificial reef group 11, using the horizontal accelerating flow to enhance the effect of upwelling. The arrangement interval between the reef group 6 and the reef group 11 is 6m, and the combined effect of horizontal accelerating flow and upwelling after the arrangement of the artificial reef group 12 is simulated. After the arrangement, the upwelling area formed by the artificial reef increases by about 1 times under the influence of horizontal accelerating flow, and the maximum flow rate of upwelling increases by about 20%. The combination of the two is more conducive to the artificial reef transporting nutrients from the bottom layer of the sea to the surface water.

[0031] In some specific embodiments, the combination method is determined in step 5 in combination with the breeding requirements. For the large-scale breeding platform 14 on the water surface, the combination of horizontal accelerating flow and upwelling is used to bring the bottom nutrients to the breeding area, improving the platform breeding efficiency. For the bottom planting area, the combination of descending flow is used to strengthen the oxygen supply of the bottom water and reduce the impact of hypoxia. Through differential combination, the breeding and ecological restoration requirements of specific sea areas are met.

[0032] Further preferably, as shown in Figure 2 The first type of combination of the artificial reef is: along the flow direction, N columns of the first type of frame body 1 with increasing height are stacked to form a first type of reef group 6 with the same guide surface and upwelling, where N is a natural number greater than 1; the flow-facing surface is vertically stacked with the first type of frame body 1, and N-1 columns on the inner side can use the first type of frame body 1 or the fifth type of frame body 5 without a guide plate; as shown in Figure 3 When considering the bidirectional reciprocating tidal flow, N columns of the second type of frame body 2 with decreasing height can be mirror-stacked on the back flow side of the first type of reef group 6, and the first type of frame body 1 and the second type of frame body 2 are arranged without spacing to form a second type of reef group 7 with upwelling on both sides; as shown in Figure 4As shown, in order to increase the back vortex area and the slow current area, a certain distance can be maintained between the first type of artificial reef group 6 and its mirror image artificial reef group to form the third type of artificial reef group 8.

[0033] like Figure 5 As shown, in a further preferred embodiment, the second combination of the artificial reefs involves stacking N columns of second-type frames 2 with progressively decreasing heights to form a fourth-type reef group 9 with the same inclined surface, capable of generating a downward flow. Since the downward flow requires a perforated bottom layer to allow water to flow from the surface to the bottom, a fifth-type frame 5 is arranged at the bottom layer of the fourth-type reef group 9. Figure 6 As shown, when considering bidirectional reciprocating currents, the fourth type of artificial reef group 9 has several first-type frames 1 with progressively increasing heights superimposed on the back current side without spacing. The second-type frames 2 are closely fitted to the first-type frames 1 to form the fifth type of artificial reef group 10 with descending currents on both sides.

[0034] Further preferred, such as Figure 7 As shown, the third combination of artificial reefs is to arrange reef cluster units vertically and at intervals. Adjacent reef cluster units are respectively composed of horizontally symmetrical third type frames 3 and fourth type frames 4 superimposed, and a funnel mouth is formed at the axis of symmetry, which gradually narrows from the front flow to the back flow, and a horizontal acceleration flow zone is formed inside the funnel mouth. The same reef cluster unit has the same guiding surface. All reef cluster units together form the sixth type of reef cluster 11, which has a flow-binding effect and generates a bottom horizontal acceleration flow. To increase stability, frames without guide plates can be arranged on the left and right sides of the third type frame 3 or the fourth type frame 4.

[0035] Further optimization of the selection is, such as Figure 8 As shown, the fourth combination of artificial reefs is: a first type of artificial reef group 6 is set at a specific distance from the funnel outlet of the sixth type of artificial reef group 11, thereby forming a seventh type of artificial reef group 12 that can generate upwelling and horizontal acceleration current, forming a suitable sea area for deployment in weak currents and significantly increasing the upwelling effect.

[0036] A further preferred embodiment of the fifth combination of artificial reefs is as follows: Figure 9 As shown, a fourth type of artificial reef group 9 is placed at a specific distance from the inlet of the funnel mouth of the sixth type of artificial reef group 11, and a first type of artificial reef group 6 is set at a specific distance from the outlet of the funnel mouth. This combination forms a larger eighth type of artificial reef group 13 with upflow, downflow and horizontal acceleration flow, thereby realizing the superposition of downflow, horizontal acceleration flow, upflow and back vortex flow.

[0037] A further preferred embodiment of the sixth combination of artificial reefs is as follows: Figure 10 As shown, the seventh type of artificial reef group 12 is arranged on the upstream and downstream sides of the large aquaculture platform 14 to enhance the bottom upflow, increase the supply of natural food, and promote fishery production and aquaculture.

[0038] In some specific embodiments, the step 6 is to design and make the artificial reef group according to the six combinations of step 5, to complete the launching and installation at a fixed position, and to conduct tracking monitoring to ensure the overall stability, the monitoring content including the fish reef structural integrity, the flow field effect sustainability and the ecological response index.

[0039] It should be noted that the above is a further detailed description of the present application in combination with specific embodiments, and the specific implementation of the present application cannot be limited to these descriptions; the size data of the present embodiment does not limit the technical solution, but only shows one specific working condition. For ordinary skilled persons in the technical field to which the present application belongs, some simple improvements and refinements can be made without departing from the concept of the present application, and all of them should be regarded as falling within the scope of protection of the present application.

Claims

1. A freely combinable artificial reef suitable for weak current sea areas, characterized by: a square frame structure with a hollow interior and six open sides, wherein: The frame structure has interlocking interfaces on three adjacent sides. The interlocking interfaces are configured to allow any two of the multiple frame structures to interlock in three-dimensional space and be fixed by detachable fasteners, thereby forming an integral reef structure. The square frame structure may or may not have a guide plate, thus forming five types of units: Type 1: The guide plate is located at the top of the frame, extending from the first side of the top of the frame to the bottom of the frame in a diagonal direction, forming a first inclined direction to generate an upward flow; Type 2: The guide plate is located at the top of the frame, its arrangement is mirror-symmetrical with the Type 1 unit, and it is used to generate a downward flow; Type 3: The guide plate is located on the side of the frame, extending horizontally from the first side of the frame to the diagonal side of the frame, forming a horizontal inclined direction to guide and accelerate the horizontal water flow; Type 4: The guide plate is located on the side of the frame, its arrangement is mirror-symmetrical with the Type 3 unit, and it is used to guide and accelerate the horizontal water flow; Type 5: No guide plate is provided.

2. The artificial reef suitable for weak current sea areas and capable of free combination as described in claim 1, characterized in that, The interlocking interface includes: a protruding structure centrally located on the side of the square frame structure, and a recessed structure located on its opposite side, wherein both the protruding structure and the recessed structure are interlocking square frames.

3. The method for arranging freely combinable artificial reefs suitable for weak current sea areas as described in claim 1, characterized in that, Includes the following steps: S1: Obtain shoreline, topography, and geological data of the proposed deployment area; S2: Calculate the tidal current process in the deployment area based on a large-scale flow field numerical model; S3: Determine the deployment area of ​​the artificial reef by combining geological conditions and tidal current field; S4: Calculate the magnitude of upwelling, downwelling, and horizontal acceleration current under different artificial reef stacking layers and arrangement spacing based on a small-scale flow field numerical model. S5: Determine the combination method of artificial reefs based on their functional requirements; S6: Complete the deployment and installation of artificial reef systems in actual sea areas.

4. The method for arranging freely combinable artificial reefs suitable for weak current sea areas as described in claim 3, characterized in that, The first combination method in S5 is: stacking N columns of first-type frames with progressively increasing height along the direction of water flow to form a first-type artificial reef group with the same guiding surface that can form an upwelling, where N is a natural number greater than 1; or, the upstream surface is made of first-type frames stacked vertically, and the inner N-1 columns are made of fifth-type frames. On the backflow side of the first type of artificial reef group, N columns of second type frames with progressively decreasing heights are superimposed without spacing to form a second type of artificial reef group with upflows on both sides. A certain distance is set between the first type of artificial reef group and its mirror image artificial reef group to form the third type of artificial reef group.

5. The method for arranging freely combinable artificial reefs suitable for weak current sea areas as described in claim 4, characterized in that, The second combination method in S5 is: superimpose N columns of second-type frames with progressively decreasing height to form a fourth-type reef group with the same inclined surface that can form a downflow, and arrange fifth-type frames at the bottom layer, where N is a natural number greater than 1; The fourth type of artificial reef group consists of N columns of first-class frames with no gaps on the back side and mirror images of each other, with the height of each column increasing progressively. These columns form the fifth type of artificial reef group with descending currents on both sides.

6. The method for arranging freely combinable artificial reefs suitable for weak current sea areas as described in claim 5, characterized in that, The third combination method in S5 is to arrange artificial reef units vertically and at intervals. Adjacent artificial reef units are formed by superimposing horizontally symmetrical third and fourth type frames, and a funnel mouth is formed at the axis of symmetry, which gradually narrows from the upstream side to the downstream side. A horizontal acceleration flow zone is formed inside the funnel mouth. The same artificial reef unit has the same guiding surface, and all artificial reef units together form the sixth type of artificial reef group.

7. The method for arranging freely combinable artificial reefs suitable for weak current sea areas as described in claim 6, characterized in that, Frames without baffles are arranged on the left and right sides of the third or fourth type of frame.

8. The method for arranging freely combinable artificial reefs suitable for weak current sea areas as described in claim 6, characterized in that, The fourth combination of artificial reefs is: setting up a first-class artificial reef group at a specific distance from the funnel-shaped outlet of the sixth-class artificial reef group to form a seventh-class artificial reef group that generates upwelling and horizontal acceleration flow.

9. The method for arranging freely combinable artificial reefs suitable for weak current sea areas as described in claim 6, characterized in that, The fifth combination of artificial reefs is as follows: a fourth type of artificial reef group is placed at a specific distance from the inlet of the funnel-shaped mouth of the sixth type of artificial reef group, and a first type of artificial reef group is set at a specific distance from the outlet of the funnel-shaped mouth, forming an eighth type of artificial reef group with upwelling, downwelling and horizontal acceleration flow.

10. The method for arranging freely combinable artificial reefs suitable for weak current sea areas as described in claim 8, characterized in that, The sixth combination of artificial reefs is to arrange the seventh type of artificial reef group on the upstream and downstream sides of the large aquaculture platform.

Images