A fishway inlet water replenishment and energy dissipation structure and design method

Abstract

The invention discloses a fishway inlet water replenishment and energy dissipation structure and a design method in the technical field of fishway design. The structure comprises a water replenishment pipe, an energy dissipation pool, a bracket, an energy dissipation cover plate and a permeable grille. The water replenishment pipe is a water replenishment steel pipe, the energy dissipation pool is a water replenishment steel pipe outlet gathering pool, the bracket is located at the top of the energy dissipation pool, and the bracket is used to provide support for the energy dissipation cover plate. The energy dissipation cover plate is located on the bracket, and the gaps between the energy dissipation cover plates are different, so that the replenishment outflow is relatively uniform, and the replenishment water flow enters the fishway from the gaps between the energy dissipation cover plates, forcing large-scale turbulent vortex groups to be converted into small-scale vortex groups; after the vortex group scale becomes smaller, the viscous shear stress is relatively easy to convert the turbulent kinetic energy into the internal energy of the fluid and dissipate it, so that the turbulent kinetic energy in the fishway is reduced, and the permeable grille is fixed on the energy dissipation cover plate, and the replenishment water body enters the fishway from the energy dissipation pool through the energy dissipation cover plate for secondary energy dissipation, which can minimize the turbulence caused by the replenishment to the water body and ensure the smooth migration of fish in the fishway.

Description

Technical Field

[0001] The invention relates to the technical field of fishway design, and in particular to a water replenishment and energy dissipation structure for a fishway inlet and a design method thereof. Background Art

[0002] The success or failure of fishway operation is mainly determined by two aspects: 1) whether the fish can find the entrance; 2) whether the fish can pass smoothly. Therefore, the effectiveness of the fishway is closely related to the swimming behavior of the target fish. Specifically, the flow-seeking characteristics of fish are mainly used in the design of the flow field at the entrance of the fishway; the swimming indicators such as the speed against flow and fatigue time of fish are mainly used in the design of the flow velocity of the fishway.

[0003] The selection of the fishway inlet location belongs to the cross-research category of fish behavior and hydraulics. Whether the setting is appropriate or not directly affects the fish passing effect of the fishway project. The biological indicators and hydrodynamic indicators of the fish passing objects are important factors that must be considered in the selection of the fishway inlet location. Theoretical studies have shown that the outflow velocity of the fishway inlet usually adopts a high-velocity water flow to attract fish. As long as the outflow velocity of the fishway inlet is less than the rushing speed of the target fish, the larger the outflow velocity of the fishway inlet and its corresponding downstream flow, the better, because the larger flow and higher flow velocity at the fishway inlet are easy for fish to find and distinguish, and it is easier to attract fish from other discharge points of the dam, which is conducive to the gathering of fish, so that it is convenient for fish to find the entrance of the fishway.

[0004] In the actual operation of the fishway, the flow rate inside the fishway varies within a small range, the flow velocity is uniform, and the average flow velocity of the cross section is low, so it is difficult to form a flow velocity advantage near the entrance to achieve a good fish-attracting effect. When the water flow velocity in the fishway entrance area is less than the fish-sensing flow velocity, measures such as water replenishment should be taken to induce fish to enter the fishway.

[0005] When the fishway is replenished with water, the replenishing water is mixed with the water in the fishway pool chamber, which will cause obvious disturbance to the water in the fishway, resulting in flow disorder in the fishway and adversely affecting the upstream migration of fish. Therefore, a water replenishment and energy dissipation structure and design method for the fishway inlet are needed to meet the stable water flow conditions in the fishway. Based on this, the present invention designs a water replenishment and energy dissipation structure and design method for the fishway inlet to solve the above problems. Summary of the invention

[0006] The object of the present invention is to provide a fishway inlet water replenishment and energy dissipation structure and a design method to solve the problems raised in the above-mentioned background technology.

[0007] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a water supply and energy dissipation structure at the inlet of a fishway, comprising a water supply pipe, an energy dissipation pool, a corbel, an energy dissipation cover plate and a permeable grille; the water supply pipe is a water supply steel pipe, the energy dissipation pool is a water supply steel pipe outlet gathering pool, the corbel is located at the top of the energy dissipation pool, and the corbel is used to provide support for the energy dissipation cover plate.

[0008] Preferably, the energy dissipation cover plate is located on the corbel, and the gaps between the energy dissipation cover plates are different, so that the water replenishment outflow is relatively uniform. The water replenishment flow enters the fishway from the gaps between the energy dissipation cover plates, forcing the large-scale turbulent vortex groups to become small-scale vortex groups. After the vortex group size becomes smaller, the viscous shear stress can more easily convert the turbulent kinetic energy into the internal energy of the fluid and dissipate it, thereby reducing the turbulent kinetic energy in the fishway, and the permeable grille is fixed on the energy dissipation cover plate.

[0009] Preferably, an unequal spacing distribution scheme of energy dissipation cover plates is adopted, and the slit width is adjusted to an arrangement type in which the slits are narrow at the head and tail and wide in the middle. The vertical flow velocity of each slit is relatively uniform, the scale of the vortex group at the outflow section of each slit is relatively small, and the viscous shear stress can more easily convert the turbulent kinetic energy into the internal energy of the fluid and dissipate it, thereby reducing the turbulent kinetic energy in the fishway.

[0010] A design method for a water replenishment and energy dissipation structure at a fishway inlet comprises the following steps:

[0011] S1: Under the two working conditions with and without energy dissipation cover, a preliminary understanding of the macroscopic flow field of the water replenishment energy dissipation pool under the water replenishment flow rate and the outlet flow velocity of the water replenishment pipe is obtained through local physical model tests;

[0012] S2: Based on the local physical model test S1, a three-dimensional hydrodynamic mathematical model is constructed, and the k-ε two-equation model is used in the turbulence model;

[0013] S3: For the unfavorable combination of test conditions, the water replenishment and energy dissipation schemes of different energy dissipation cover types are further calculated by means of numerical simulation technology - three-dimensional hydrodynamic mathematical model; the water replenishment and energy dissipation effect is evaluated by the uniformity of the flow field distribution inside the fishway and the turbulent energy parameter of the fishway hydraulic factor is lower than 0.035m2 / s2;

[0014] S4: Conduct physical model tests again based on S3 to further refine the detailed structure of the water replenishment and energy dissipation cover plate and determine the final type of the energy dissipation cover plate.

[0015] Preferably, the replenishing water body enters the fishway from the energy dissipation pool through the energy dissipation cover plate for secondary energy dissipation.

[0016] Preferably, in S1, the length of the energy dissipation pool is preliminarily determined to be a=2H~3H, the height is b=1B~2B, the height of the water replenishment energy dissipation pipe from the pool bottom is c=1 / 3b~1 / 2b, H is the normal operating water depth of the fishway, and B is the net width of the fishway pool chamber.

[0017] Preferably, in S2, the measured results of the physical model under the working condition of S1 are used to verify the mathematical model so that it can accurately reflect the state of water flow movement.

[0018] Preferably, in S3, turbulent energy may be a hydraulic factor with a more direct impact; turbulent energy represents the kinetic energy carried by fluid turbulence, reflecting the strength of fluid turbulence; the turbulent energy expression is as follows:

[0019]

[0020]

[0021] Where ui is the instantaneous velocity, m / s; is the time average velocity, m / s; u′ i is the pulsation speed, m / s; u′ x , u′ y , u′ z They are the pulsation speeds along three different directions: x, y, and z, and the unit is m / s.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] The flow pattern of the water replenishment flow in the fishway energy dissipation pool is turbulent, the three-dimensional structural characteristics of the flow field are very complex, and the scale of the turbulent flow field is small. The conventional propeller flow meter used in the physical model test has limited ability to capture and measure flow field information, but can provide macroscopic flow field structure information. Through the physical model test, we can have a preliminary understanding of the macroscopic flow field of the water replenishment energy dissipation pool, but it is insufficient as a technical means to optimize the water replenishment energy dissipation scheme.

[0024] The length a of the energy dissipation pool is 2H~3H, and the height b is 1B~2B. The purpose is to allow the water in the water supply pipe to fully roll in the energy dissipation pool; the height c of the water supply pipe from the bottom of the energy dissipation pool is 1 / 3b~1 / 2b. The purpose is to allow the water inside the energy dissipation pool to have a certain thickness, fully offset the water flow inside the water supply pipe, and achieve the purpose of one-time energy dissipation inside the energy dissipation pool.

[0025] The water replenishment and energy dissipation pool is the "threshold" for migratory fish. It is not enough to rely solely on flow field observation results to assess whether the requirements for fish migration are met. Fish migration requires a high turbulent kinetic energy factor for the water flow. Turbulent kinetic energy is an indicator of the pulse kinetic energy of the water flow, and this value cannot be obtained by existing observation equipment.

[0026] Develop three-dimensional hydrodynamic numerical simulation technology, verify the mathematical model through physical model test data, and on this basis analyze the detailed structure of the energy dissipation pool flow field, solve parameters such as turbulent kinetic energy, and optimize the energy dissipation cover scheme; and finally determine the type of energy dissipation cover through physical model tests through the preferred design scheme. The replenishment water enters the fishway from the energy dissipation pool through the energy dissipation cover for secondary energy dissipation, which can minimize the turbulence of the water body caused by the replenishment and ensure the smooth migration of fish in the fishway.

[0027] Of course, any product implementing the present invention does not necessarily need to achieve all of the advantages described above at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for describing the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0029] Figure 1 It is a structural schematic diagram of the present invention;

[0030] Figure 2 It is a schematic cross-sectional view of the structure of the present invention;

[0031] Figure 3 This is a schematic diagram of the measurement point arrangement of the scheme without energy dissipation cover plate in working condition 1 in an embodiment of the present invention;

[0032] Figure 4 It is a schematic diagram of measuring point arrangement of working condition 2 with energy dissipation cover plate in an embodiment of the present invention;

[0033] Figure 5 A schematic side view of a three-dimensional solid model in an embodiment of the present invention;

[0034] Figure 6 Schematic diagram of the energy dissipation cover plate in working condition 3 in an embodiment of the present invention;

[0035] Figure 7 Schematic diagram of the energy dissipation cover plate in working condition 4 in an embodiment of the present invention;

[0036] Figure 8 Schematic diagram of flow velocity distribution calculation for working condition 3 in an embodiment of the present invention;

[0037] Fig. 9 This is a schematic diagram of calculating the turbulent energy distribution of the flow field under working condition 3 in an embodiment of the present invention;

[0038] Fig.10 Schematic diagram of flow velocity distribution calculation in working condition 4 in an embodiment of the present invention;

[0039] Fig.11 Schematic diagram of calculating the turbulent energy distribution of the flow field in working condition 4 in an embodiment of the present invention;

[0040] Fig.12 Schematic diagram of the energy dissipation cover plate in working condition 5 in an embodiment of the present invention;

[0041] Fig.13 Schematic diagram of the energy dissipation cover plate in working condition 6 in an embodiment of the present invention.

[0042] In the accompanying drawings, the components represented by the reference numerals are listed as follows:

[0043] 1. Water supply pipe; 2. Energy dissipation pool; 3. Corbel; 4. Energy dissipation cover; 5. Permeable grille. DETAILED DESCRIPTION

[0044] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0045] See also Figures 1 to 4 The present invention provides a technical solution for a water replenishment and energy dissipation structure and design method of a fishway inlet: comprising a water replenishment pipe 1, an energy dissipation pool 2, a bracket 3, an energy dissipation cover plate 4, and a permeable grille 5. The net width of the fishway pool chamber is B = 2.5m, and the normal operating water depth is H = 2.5m. The water supply pipe 1 as the source of water supply flow has a diameter of 60cm, a maximum water supply flow of 1m3 / s, an outlet flow rate of 1m / s, and a pipe diameter that is vertically downward, discharging the water in the pipe into the energy dissipation pool; the length of the energy dissipation pool 2 is a=2H~3H, which is 7m, the height is b=1B~2B, which is 3m, the distance from the bottom surface of the energy dissipation pool 2 is c=1 / 3b~1 / 2b, which is 1m, and the width is the width of the fishway pool; the bracket 3 is located at the top of the energy dissipation pool 2, providing support for the energy dissipation cover plate 4; the gaps between the 4 energy dissipation covers are different, so that the water supply outflow is relatively uniform, and the water supply flow enters the fishway from the gaps between the covers, forcing the large-scale turbulent vortex to be transformed into a small-scale vortex. When the vortex scale becomes smaller, the viscous shear stress is easier to convert the turbulent kinetic energy into the internal energy of the fluid and dissipate it, so that the turbulent kinetic energy in the fishway is reduced, which is conducive to the migration of fish. The permeable grille 5 with a size of 2.5 cm×2.5 cm is fixed on the energy dissipation cover plate 4 and can effectively prevent the fish in the fishway pool from swimming into the energy dissipation pool 2 .

[0046] A method for designing a water replenishment and energy dissipation structure at a fishway inlet comprises the following steps:

[0047] S1: Carry out local model tests on the flow conditions of two schemes with and without energy dissipation cover plates, and use a propeller flow meter to measure the flow velocity. The arrangement of measurement points for the design scheme is shown in Figure 3 , Figure 4 , the measured results of flow velocity in the direction of water flow are shown in the following table:

[0048]

[0049] Without energy dissipation cover:

[0050] The #1 measuring point at section 0+01.10 is located near the bottom of the water replenishment and energy dissipation pool, with a large flow velocity, and is significantly affected by the outflow from the water replenishment pipe. The flow velocities at measuring point #1 at other observation sections in the water replenishment and energy dissipation pool, such as sections 0+02.80 and 0+04.90, are the maximum flow velocities at different water depths in the same section. Backflow occurs near the surface of section 0+04.90 (measurement points #4 and #5). This shows that after the outflow from the water replenishment pipe, the mainstream moves close to the bottom of the energy dissipation pool, and is affected by the rising bank of the energy dissipation pool, generating a certain scale of backflow near the surface. After the water flows out of the energy dissipation pool and enters the downstream fishway, the flow velocity near the bottom is relatively low, while the flow velocity near the surface is relatively high (section 0+011.00), and the flow velocity distribution is basically consistent with the flow velocity distribution of the ordinary fishway pool.

[0051] With energy dissipation cover:

[0052] The three measuring points of section 0+01.10 are arranged in the fishway on the upper part of the cover plate. The flow through the section is mainly the flow of the fishway, so the flow velocity is relatively small. The reverse flow velocity appears at the #2 measuring point of section 0+02.80. This section is located near the front edge of the cover plate. The #2 measuring point is located below the elevation of the cover plate. The flow of the fishway flows through the cover plate, which will produce a certain scale of backflow. The surface flow velocities of sections 0+02.80 and 0+04.90 are both low. There is also backflow on the surface of section 0+04.90. This is caused by the backflow generated by the upward movement of the replenishment water flow along the riser and the intersection of the water flow in the fishway. After the water flows out of the energy dissipation pool and enters the downstream fishway, the flow velocity near the bottom is relatively low, while the flow velocity near the surface is relatively high (section 0+011.00). The flow velocity distribution is basically consistent with the flow velocity distribution of the ordinary fishway pool.

[0053] After adding the cover, the "flowering" phenomenon of the replenishment water flow in the working condition without the energy dissipation cover disappeared, but the flow field structure is still very complex. The main characteristics of the flow field structure of the replenishment energy dissipation pool are small scale and complex changes. It is difficult to capture the complete flow field structure through actual measurement. In addition, the replenishment energy dissipation pool is the "threshold" of migratory fish. It is not enough to rely solely on the flow field observation results to assess whether it meets the requirements of fish migration.

[0054] In summary, for a certain flow rate and velocity of replenishment outflow, physical model tests can provide a preliminary understanding of the macroscopic flow field of the replenishment energy dissipation pool, but the technical means for optimizing the replenishment energy dissipation scheme are insufficient. Therefore, it is very necessary to develop three-dimensional hydrodynamic numerical simulation technology, verify the model through physical model test data, analyze the detailed structure of the energy dissipation pool flow field on this basis, solve the turbulent kinetic energy parameters, and further carry out the optimization of the replenishment energy dissipation scheme.

[0055] S2: Based on the local physical model test S1, a three-dimensional hydrodynamic mathematical model is constructed. The turbulence model adopts the k-ε two-equation model. The finite difference method is used for discretization. The simulation scope is mainly the water replenishment energy dissipation pool, which is 7.0m long, 3.0m deep, and 2.5m wide. The upstream and downstream of the energy dissipation pool are connected to the fishway pool room. The three-dimensional solid model is as follows Figure 5 shown.

[0056] The calculated results of the flow velocity in the downstream direction of the four sections of 0+01.10, 0+02.80, 0+04.90, and 0+07.00 under the two schemes were compared with the measured results of the physical model test. The trend of the vertical distribution of the flow velocity of the digital model and the physical model is basically consistent, especially the simulation of the backflow is relatively accurate. The difference in the flow velocity in the downstream direction on the same vertical line is very large, which also confirms the complexity of the flow field structure of the energy dissipation pool. It is acceptable that the calculated results of the vertical flow velocity distribution of some sections have a certain error with the measured value. In general, the three-dimensional hydrodynamic mathematical model established by the present invention can accurately depict the flow field structure of the energy dissipation pool, and can be used as a technical means to optimize the water replenishment and energy dissipation scheme.

[0057] S3: Select the most unfavorable working condition of the combination of the fishway operating water depth and water replenishment flow rate: the water replenishment flow rate of the water replenishment pipe is close to the upper limit of the water replenishment capacity (according to the value of 2.0m3 / s), and the fishway operating water depth is relatively small. This flow combination working condition is the most unfavorable combination working condition. Based on this working condition, the fishway water replenishment energy dissipation cover solution is further optimized through numerical simulation technology.

[0058] Table numerical simulation calculation conditions selection

[0059]

[0060] The flow field distribution and turbulent energy distribution under various working conditions are calculated as follows: Figures 8 to 11 As shown:

[0061] In terms of the flow field of the fishway profile, compared with condition 3, the outlet slit of the cover plate at the tail of the energy dissipation and water replenishment pool in condition 4 is narrowed or even eliminated, forcing the outflow velocity of each outlet slit to be relatively uniform. Under condition 4, the plane flow field has a channel suitable for fish migration. More importantly, within the water depth range of 0.875H to 0.225H in the fishway, there is still a large area near the side wall with turbulent energy less than 0.035m2 / s2. By adjusting the slit width of the cover plate, the water replenishment outflow is relatively uniform, and the turbulent energy of the water flow in the fishway can also be reduced.

[0062] S4: Conduct physical model tests again based on S3 to further refine the detailed structure of the water replenishment and energy dissipation cover plate and determine the final type of the energy dissipation cover plate.

[0063] Condition 5: The cover is 7.00m long, 2.50m wide, and has a total area of ​​17.5m2. The width of the left and right side strips is 0.45m each; there are 21 cover strips, 0.2m wide (20 strips) and 0.46m wide (1 strip); there are 17 seams, 0.30m wide (1 strip) and 0.14m wide (16 strips), and the water flow area is 4.06m2, accounting for 23.22% of the total area. Fig.12 The measured vertical flow velocity is shown in the table below.

[0064]

[0065] Under this scheme, the vertical flow velocity distribution of each seam is uneven, the vertical flow velocity of the seams at the head and tail of the energy dissipation pool is too large, and the vertical flow velocity of the seams in the middle of the energy dissipation pool is too small. It is necessary to further reduce the width of the seams at the head and tail of the energy dissipation pool and increase the seam width of the cover plate in the middle of the energy dissipation pool.

[0066] Condition 6: 21 cover strips, 0.20m wide (20 strips), 0.46m wide (1 strip); 17 seams, 0.05m wide (2 strips), 0.29m wide (5 strips), 0.10m wide (11 strips), water flow area 4.06m2, accounting for 23.22% of the total area, see Fig.12 , the measured vertical flow velocity is shown in the table below.

[0067]

[0068]

[0069] By adopting the scheme of unequally spaced cover distribution, the slit width is adjusted to a layout type with narrow ends at the head and tail and wide in the middle of the energy dissipation pool. The vertical flow velocity of each slit is relatively uniform, the scale of the vortex group at the outflow section of each slit is relatively small, and the viscous shear stress can easily convert the turbulent kinetic energy into the internal energy of the fluid and dissipate it, thereby reducing the turbulent kinetic energy in the fishway and facilitating fish migration.

[0070] In the description of this specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0071] The preferred embodiments of the present invention disclosed above are only used to help illustrate the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to the specific implementation methods described. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A design method for a water replenishment and energy dissipation structure at a fishway inlet, characterized by: The water replenishment and energy dissipation structure at the fishway inlet comprises a water replenishment pipe (1), an energy dissipation pool (2), a bracket (3), an energy dissipation cover plate (4) and a permeable grille (5); the water replenishment pipe (1) is a water replenishment steel pipe, the energy dissipation pool (2) is a water replenishment steel pipe outlet water collection pool, the bracket (3) is located at the top of the energy dissipation pool (2), and the bracket (3) is used to provide support for the energy dissipation cover plate (4); The energy dissipation cover plate (4) is located on the corbel (3), and the gaps between the energy dissipation cover plates (4) are different, so that the replenishment water outflow is relatively uniform. The replenishment water flow enters the fishway from the gaps between the energy dissipation cover plates (4), forcing the large-scale turbulent vortex group to be transformed into a small-scale vortex group; after the vortex group size becomes smaller, the viscous shear stress can more easily convert the turbulent kinetic energy into the internal energy of the fluid and dissipate it, so that the turbulent kinetic energy in the fishway is reduced. The permeable grille (5) is fixed on the energy dissipation cover plate (4); By adopting the unequal spacing distribution scheme of the energy dissipation cover plates (4), the slit width is adjusted to an arrangement type in which the energy dissipation pool (2) is narrow at the front and rear ends and wide in the middle, the vertical flow velocity of each slit is relatively uniform, the scale of the vortex group at the outflow section of each slit is relatively small, and the viscous shear stress can easily convert the turbulent kinetic energy into the internal energy of the fluid and dissipate it, thereby reducing the turbulent kinetic energy in the fishway; The design method includes the following steps: S1: Under the two working conditions with and without energy dissipation cover, a preliminary understanding of the macroscopic flow field of the water replenishment energy dissipation pool under the water replenishment flow rate and the outlet flow velocity of the water replenishment pipe is obtained through local physical model tests; S2: Based on the local physical model test S1, a three-dimensional hydrodynamic mathematical model is constructed, and the k-ε two-equation model is used in the turbulence model; S3: For the unfavorable combination of test conditions, the water replenishment and energy dissipation schemes of different energy dissipation cover types are further calculated by means of numerical simulation technology - three-dimensional hydrodynamic mathematical model; the water replenishment and energy dissipation effect is evaluated by the uniformity of the flow field distribution inside the fishway and the turbulent energy parameter of the fishway hydraulic factor is lower than 0.035m2 / S2; S4: Conduct physical model tests again based on S3 to further refine the detailed structure of the water replenishment and energy dissipation cover plate and determine the final type of the energy dissipation cover plate.

2. The design method of a water replenishment and energy dissipation structure at a fishway inlet according to claim 1 is characterized by: The replenishment water enters the fishway from the energy dissipation pool through the energy dissipation cover for secondary energy dissipation.

3. The design method of a water replenishment and energy dissipation structure at a fishway inlet according to claim 1 is characterized in that: In S1, it is preliminarily determined that the length of the energy dissipation pool is a=2~3H, the height is b=1~2B, the height of the water replenishment energy dissipation pipe from the pool bottom is c=1 / 3~1 / 2b, H is the normal operating water depth of the fishway, and B is the net width of the fishway pool chamber.

4. The design method of a water replenishment and energy dissipation structure at a fishway inlet according to claim 1 is characterized in that: In S2, the measured results of the physical model under the working condition of S1 are used to verify the mathematical model so that it can accurately reflect the state of water flow movement.

5. The design method of a water replenishment and energy dissipation structure at a fishway inlet according to claim 1 is characterized in that: In S3, turbulent energy is a hydraulic factor with a more direct impact; turbulent energy represents the kinetic energy carried by fluid turbulence and reflects the strength of fluid turbulence; the expression of turbulent energy is as follows: In the formula, is the instantaneous speed, m / s; is the time average velocity, m / s; is the pulsation speed, m / s; , , They are the pulsation speeds along three different directions: x, y, and z, and the unit is m / s.

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