A method and system for determining the structure of a fishway resting pool

Abstract

The present invention discloses a method and system for determining the structure of a fishway rest pool, the method comprising: determining the mainstream of the water flow in the rest pool according to the preset structural parameters of the rest pool; if the boundary of the mainstream intersects with the pool wall of the rest pool, improving the preset structural parameters of the rest pool; determining the mainstream that does not intersect with the pool wall from the mainstreams corresponding to each group of improved structural parameters; obtaining the structural parameters that meet the preset conditions from the structural parameters corresponding to the non-intersecting mainstreams, and obtaining the fishway rest pool structure. The present invention proposes an improvement plan for the key design parameters of the fishway rest pool according to the influence of the flow field distribution and hydraulic characteristics in the rest pool on the migration of fish, thereby optimizing and adjusting the unfavorable flow field and hydraulic characteristics in the rest pool, so as to improve the water flow conditions in the rest pool, make the recirculation area evenly distributed, be more conducive to the migration of fish in the rest pool and the recovery of physical strength, and better play the function of the fishway rest pool.

Description

Technical Field

[0001] The invention discloses a method and a system for determining the structure of a fishway rest pool, belonging to the technical field of water conservancy engineering. Background Art

[0002] A fishway is a channel built on a sluice or dam to protect the habits of fish and provide a channel for fish migration. It mainly controls the flow rate of water so that fish can overcome the resistance of the water flow and successfully complete the upstream migration, thereby assisting fish to complete their breeding cycle.

[0003] The commonly used fishway at present is a vertical vertical slit fishway with a rectangular cross-section. The vertical slit fishway is also called a trough fishway. The fish opening between the fishway chambers is a vertical slit from top to bottom. The water flows down from the vertical slits arranged in the middle or on both sides. It has a simple structure, stable flow, good energy dissipation effect, strong adaptability to the inlet and outlet water levels, and can meet the upstream needs of fish with different preferences for water depth. It is widely used.

[0004] The resting pool is one of the common fishway chambers in the vertical seam fishway structure layout and is an important part of the fishway. The resting pool is usually located in the straight section and the turning section of the fishway. By setting up the resting pool, it can provide a resting place for fish on the way upstream, avoiding the failure of fish upstream due to excessive fatigue. The fishway design specifications in the prior art stipulate that a resting pool should be set up every 10 to 20 partitions. The resting pool should have a flat bottom and its length should not be less than 2 times the length of the chamber. The above-mentioned fishway design specifications only limit the structure of the resting pool, and it does not clarify the hydraulic characteristics in the resting pool, resulting in the mainstream in the resting pool in the actual application process. There will be unfavorable flow states such as hitting the wall and sticking to the wall, and the above-mentioned unfavorable flow state will affect the upstream efficiency of the fish passing through and affect the migration of fish. Summary of the invention

[0005] The purpose of the present application is to provide a method and system for determining the structure of a fishway rest pool, so as to solve the technical problem in the prior art that the fishway rest pool has unfavorable flow states such as mainstream hitting the wall and sticking to the wall, which affects the migration of fish.

[0006] A first aspect of the present invention provides a method for determining a fishway resting pool structure, comprising:

[0007] Step 1: determining the main flow of water in the rest pool according to the preset structural parameters of the rest pool;

[0008] Step 2: if the boundary of the main flow intersects with the wall of the rest pool, then improving the structural parameters of the preset rest pool;

[0009] Step 3, determining the mainstream that does not intersect with the pool wall from the mainstreams corresponding to each set of improved structural parameters;

[0010] Step 4: From the structural parameters corresponding to the disjoint main streams, obtain the structural parameters that meet the preset conditions to obtain the fishway rest pool structure.

[0011] Preferably, improving the structural parameters of the preset rest pool specifically includes:

[0012] Obtaining the intersection position of the boundary of the mainstream in the rest pool and the pool wall;

[0013] Determine a plurality of improvement points according to the intersection positions;

[0014] Rectifier plates are arranged at the improved points to obtain multiple groups of structural parameters of the improved rest pool.

[0015] Preferably, a rectifier plate is arranged at the improved point to obtain multiple sets of improved structural parameters of the rest pool, specifically including:

[0016] M sizes of rectifier plates are set at one of the improved points to obtain M groups of improved rest pool structural parameters, and this step is repeated until rectifier plates are set at all improved points to obtain multiple groups of improved rest pool structural parameters.

[0017] Preferably, a plurality of improvement points are determined according to the intersection position, specifically including:

[0018] Obtaining the interval range corresponding to the intersection position;

[0019] The upstream boundary point and the midpoint of the interval range are used as improvement points.

[0020] Preferably, from the structural parameters corresponding to the disjoint main streams, structural parameters meeting preset conditions are obtained to obtain the fishway rest pool structure, including:

[0021] Obtaining the maximum flow velocity trajectory, the distribution of the maximum flow velocity value along the path, and the kinetic energy distribution of the non-intersecting mainstream;

[0022] Obtaining hydraulic characteristic parameters of the recirculation zones on both sides of the non-intersecting main streams;

[0023] According to the maximum flow velocity trajectory, the distribution of the maximum flow velocity value along the way, the kinetic energy distribution and the hydraulic characteristic parameters of the recirculation area, the structural parameters that meet the preset conditions are determined to obtain the fishway rest pool structure.

[0024] Preferably, obtaining the maximum flow velocity trajectory line and the distribution of the maximum flow velocity value along the non-intersecting mainstream specifically includes:

[0025] A rectangular coordinate system is constructed with the length direction of the rest pool as the X-axis and the width direction of the rest pool as the Y-axis;

[0026] On the X-axis, multiple cross sections of the rest pool are intercepted at set intervals;

[0027] Obtaining the maximum flow velocity of the non-intersecting mainstreams in each of the cross sections and their corresponding positions;

[0028] According to the maximum flow velocity value and its corresponding position, a maximum flow velocity trajectory line and the distribution of the maximum flow velocity value along the path are constructed.

[0029] Preferably, obtaining the kinetic energy distribution of the non-intersecting main streams specifically includes:

[0030] The average kinetic energy of the non-intersecting main streams is determined according to a first formula, wherein the first formula is:

[0031]

[0032] In the formula, v x is the speed of the improved mainstream in the x direction, v y is the speed of the main stream in the y direction, v z is the vertical velocity of the improved mainstream, k is the average kinetic energy;

[0033] The distribution amount is determined according to the average kinetic energy, and the contour lines of the distribution amount are obtained to obtain the kinetic energy distribution of the non-intersecting mainstreams.

[0034] Preferably, obtaining the hydraulic characteristic parameters of the recirculation zones on both sides of the non-intersecting main streams specifically includes:

[0035] Determining swimming parameters of the fish object, wherein the swimming parameters include a swimming water layer;

[0036] Determine the height cross section of the rest pool in height according to the swimming water layer;

[0037] The influence domain of the recirculation zone on both sides of the non-intersecting main flow on the height cross section is determined.

[0038] Preferably, determining the influence domain of the recirculation zone on both sides of the non-intersecting main flow on the height cross section specifically includes:

[0039] The influence domain of the recirculation zone on both sides of the non-intersecting mainstream on the height cross section is determined according to the second formula, and the second formula is:

[0040] D=(hx / L)×(hy / B)

[0041] Wherein, hx is the length of the recirculation zone along the x-axis direction, hy is the length of the recirculation zone along the y-axis direction, L is the length of the rest pool, and B is the width of the rest pool.

[0042] A second aspect of the present invention discloses a fishway rest pool structure determination system, comprising:

[0043] A first mainstream determination module, the mainstream determination module is used to determine the mainstream of the water flow in the rest pool according to preset structural parameters of the rest pool;

[0044] An improvement module, wherein the improvement module is used to improve the structural parameters of the preset rest pool when the boundary of the main flow intersects with the pool wall of the rest pool;

[0045] A second mainstream determination module, the second mainstream determination module is used to determine the mainstream that does not intersect with the pool wall from the mainstreams corresponding to each group of improved structural parameters;

[0046] A structure determination module is used to obtain structural parameters that meet preset conditions from the structural parameters corresponding to the non-intersecting main streams to obtain the fishway rest pool structure.

[0047] Compared with the prior art, the fishway rest pool structure determination method and system of the present invention have the following beneficial effects:

[0048] The present invention utilizes a numerical calculation method to establish a numerical model of a vertical slot fishway rest pool, and proposes an improvement plan for key design parameters of the fishway rest pool according to the influence of the flow field distribution and hydraulic characteristics in the rest pool on the migration of fish, thereby optimizing and adjusting the unfavorable flow field and hydraulic characteristics in the rest pool to improve the water flow conditions in the rest pool, making the recirculation area evenly distributed, which is more conducive to the migration and physical recovery of fish in the rest pool, and better playing the function of the fishway rest pool. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 A flow chart of a method for determining a fishway rest pool structure provided by the present invention;

[0050] Figure 2 A schematic diagram of the structure of a hierarchical grid in the MIKE software in an embodiment of the present invention;

[0051] Figure 3 Schematic diagram of the structure of the sigma vertical grid in an embodiment of the present invention;

[0052] Figure 4 Schematic diagram of the structure of a sigma / z-level hybrid vertical grid in an embodiment of the present invention;

[0053] Figure 5 A schematic diagram of the structure of a fishway rest pool structure determination system provided by the present invention;

[0054] Figure 6 It is a structural schematic diagram of the calculation area in a specific embodiment of the present invention;

[0055] Figure 7 A plane grid division diagram of the calculation area in a specific embodiment of the present invention;

[0056] Figure 8 It is a distribution diagram of water depth contours in a rest pool in a specific embodiment of the present invention;

[0057] Fig. 9 It is a distribution diagram of water level contour lines in a rest pool in a specific embodiment of the present invention;

[0058] Fig.10 It is a flow velocity distribution diagram in the rest pool in a specific embodiment of the present invention;

[0059] Fig.11 It is a flow velocity vector distribution diagram in the rest pool in a specific embodiment of the present invention;

[0060] Fig.12 It is a line diagram of the maximum flow velocity trajectory of the rest pool in a specific embodiment of the present invention;

[0061] Fig.13 It is a distribution diagram of the maximum flow velocity along the rest pool in a specific embodiment of the present invention;

[0062] Fig.14 k in the rest pool in the specific embodiment of the present invention 0.5 / v max distributed;

[0063] Fig.15 1 is a flow velocity vector diagram of the rest pool in different schemes in a specific embodiment of the present invention, (a) is a flow velocity vector diagram of the rest pool in the original scheme, (b) is a flow velocity vector diagram of the rest pool in scheme 1, (c) is a flow velocity vector diagram of the rest pool in scheme 2, (d) is a flow velocity vector diagram of the rest pool in scheme 3, (e) is a flow velocity vector diagram of the rest pool in scheme 4, and (f) is a flow velocity vector diagram of the rest pool in scheme 5;

[0064] Fig.16 It is a line diagram of the maximum flow velocity trajectory of the rest pool in different schemes in the specific embodiment of the present invention;

[0065] Fig.17 It is a distribution diagram of the maximum flow velocity along the rest pool of different schemes in the specific embodiment of the present invention;

[0066] Fig.18 k in the rest pool in different schemes in the specific embodiments of the present invention 0.5 / v max Distribution, (a) is the k in the rest pool of the original scheme 0.5 / v max distribution, (b) is the k in the rest pool of Scheme 1 0.5 / v max distribution, (c) is the k in the rest pool of Scheme 20.5 / v max distribution, (d) is the k in the rest pool of Scheme 3 0.5 / v max distribution, (e) is the k in the rest pool of Scheme 4 0.5 / v max distribution, (f) is the k in the rest pool of Scheme 5 0.5 / v max distributed.

[0067] In the figure, 101 is the first mainstream determination module; 102 is the improvement module; 103 is the second mainstream determination module; and 104 is the structure determination module. DETAILED DESCRIPTION

[0068] In the following description, specific details such as specific system structures, technologies, etc. are provided for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present invention. However, it should be clear to those skilled in the art that the present invention may be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to prevent unnecessary details from obstructing the description of the present invention.

[0069] The first aspect of the present invention discloses a method for determining the structure of a fishway resting pool, the process of which is shown in FIG1 and comprises:

[0070] Step 1: Determine the mainstream of the water flow in the rest pool according to the preset structural parameters of the rest pool.

[0071] The structural parameters of the rest pool preset in the embodiment of the present invention can be the structural parameters of the fishway rest pool that has been designed but not yet started to be constructed, or can be the structural parameters of the fishway rest pool that is under construction. The fishway under study is a vertical vertical slit fishway. Before obtaining the structural parameters of the rest pool, it is necessary to obtain the total length of the vertical vertical slit fishway, the number and setting positions of the partitions with guide plates, the number of pool chambers and rest pools formed, the slit width, and the width, length and bottom slope of each pool chamber and each rest pool. The structural parameters of the rest pool include the slit width on both sides of the rest pool, the width, length and bottom slope of the rest pool.

[0072] In the embodiment of the present invention, step 1 specifically includes:

[0073] Step 1.1, obtain the structural parameters of the preset rest pool, and construct a hydrodynamic numerical model of the rest pool according to the structural parameters.

[0074] In the embodiment of the present invention, the structural parameters of the preset rest pool are obtained, and the hydrodynamic numerical model of the rest pool is constructed according to the structural parameters. Specifically, the hydrodynamic numerical model of the rest pool is constructed by using MIKE software in combination with the structural parameters of the preset rest pool.

[0075] MIKE software is suitable for simulating one-dimensional river network hydrodynamic systems and two-dimensional floodplains and coastal areas, macro-basin engineering layout analysis and basin flood scheduling research, and micro-water flow simulation.

[0076] The basic control equation used in the MIKE software is:

[0077] Continuity equation:

[0078]

[0079] The horizontal momentum equation in the x-direction is:

[0080]

[0081] The horizontal momentum equation in the y direction is:

[0082]

[0083] Where u, v, w are the water velocity components in the x, y, and z directions in the Cartesian coordinate system, respectively; t is time; η is the surface elevation; d is the still water depth; h = η + d is the total water depth; f = 2Ωsinφ is the Coriolis parameter, Ω is the angular velocity of rotation, φ is the geographic latitude; g is the gravitational acceleration; ρ is the density of water; s xx ,s xy ,s yx and yy is the component of the radiation stress tensor; v t is the vertical eddy viscosity coefficient; p a is the atmospheric pressure; ρ 0 is the reference density of water; S is the flow rate of the point source, (u s , v s ) is the source-sink flow velocity, (F u , F v ) is the horizontal stress term, which is described by pressure gradient correlation and simplified to formula (4) and formula (5):

[0084]

[0085]

[0086] Where A is the horizontal eddy viscosity.

[0087] The boundary conditions in the x, y, and z directions are:

[0088] (1) z = η

[0089]

[0090]

[0091] (2) z = -d

[0092]

[0093]

[0094] In the formula, (τ sx ,τ sy ) is the surface wind pressure in the x and y directions; (τ bx ,τ by ) is the bottom pressure in the x and y directions.

[0095] The following relationship can be established with the water depth and average flow velocity through Xie Cai's formula:

[0096]

[0097]

[0098] Where C is the Xie Cai coefficient.

[0099] The MIKE software also involves the standard k-ε turbulence model.

[0100] In the k-ε turbulence model, the eddy viscosity v t It is derived from the turbulence parameters k and ε.

[0101]

[0102] Where k is the turbulent kinetic energy per unit mass (TKE), ε is the turbulent dissipation rate, and C μ is an empirical constant.

[0103] The turbulent kinetic energy k and the turbulent energy dissipation rate ε can be obtained from the following transport equations:

[0104]

[0105]

[0106] Where, t is time, unit is s; μ, v t is the viscosity coefficient and the eddy viscosity coefficient, in m 2 / s; ρ is density, unit: kg / m 3 ; k is the turbulent kinetic energy per unit mass, unit m 2 / s 2 ; ε is the turbulent dissipation rate, unit is m 3 / s 3 ; G kis the term for turbulent energy generation; u is the coordinate component of the time-averaged velocity component in the x direction, in m / s, and the other constants are taken as C μ =0.09,σ ε =1.3,σ k =1.0, C ε1 =1.44, C ε2 =1.92.

[0107] The embodiment of the present invention utilizes MIKE software, in conjunction with the structural parameters of the preset rest pool, when building the hydrodynamic numerical model of the rest pool, it is necessary to carry out grid division, MIKE software has three kinds of grid division modes, namely rectangular flow model (FlowModel), unstructured grid flow model (Flow Model FM) and curvilinear grid flow model (Curvilinear Flow Model). Wherein the unstructured grid flow model is a kind of triangular grid, and the model divides the calculation area into triangular grids, and the size (resolution) of the grid is determined by the simulation area size and specific requirements, and the smaller the grid, the higher the calculation accuracy, and the longer the time consuming. This model adopts finite element solution, can well simulate the flow field of natural river course and or the surrounding area of ​​water structure. According to the characteristics of this model structure, the present invention adopts unstructured triangular grid to carry out the division of plane grid to the calculation area.

[0108] When performing calculations with MIKE 3 FM, use a hierarchical grid, such as Figure 2 As shown in the figure, an unstructured grid is used in the horizontal domain, while a structured grid is used in the vertical domain. Vertical grids can be represented by sigma coordinates or combined sigma / z-level coordinates. For hybrid sigma / z-level grids, sigma coordinates are used from the free surface to the specified depth, and z-level coordinates are used below. Different types of vertical grids are shown in the figure. Figure 3 and Figure 4 shown. Figure 4 The thick solid line in the middle represents the interface between the z-level domain and the sigma-level domain. The most important advantage of using sigma coordinates is that they can accurately represent water depth measurements and provide consistent resolution near the riverbed. However, the z-level coordinates are inaccurate in representing water depth, which may lead to unrealistic flow velocities near the bottom, so the vertical grid of the present invention uses a sigma grid.

[0109] The solution method of the MIKE software in the present invention is: the spatial discretization of the MIKE 3 hydrodynamic module adopts the finite volume method (control volume method) of the unit center, which divides the area into a series of non-repetitive control volumes so that there is a control volume around each grid node; then the differential equation to be solved is integrated for each control volume to obtain a set of discrete equations. The physical meaning of the discrete equation is the conservation principle of the dependent variable in a control volume of finite size, which is the same as the conservation principle of the dependent variable expressed by the differential equation in an infinitely small control volume. The discrete equation obtained by the finite volume method requires that the integral conservation of the dependent variable is satisfied for any set of control volumes, and is also satisfied for the entire calculation area.

[0110] The general equation form for the time integral is:

[0111]

[0112] For three-dimensional simulations, the time integration is semi-implicit. That is, the horizontal terms are treated implicitly and the vertical terms are treated implicitly, partially explicit, or partially implicitly. Consider the general semi-implicit form of the equation:

[0113]

[0114] The subscripts h and v denote the horizontal term and the vertical term, respectively, and the superscripts I and V denote the non-viscous term and the viscose term, respectively.

[0115] A low-order expression for the three-dimensional shallow water equation can be written as:

[0116]

[0117] The horizontal terms are integrated using the first-order explicit Euler formula, and the vertical terms are integrated using the second-order implicit trapezoidal rule. The expression of the high-order method is:

[0118]

[0119]

[0120] The horizontal terms are integrated using the second-order Runge Kutta and the vertical terms are integrated using the second-order implicit trapezoidal rule.

[0121] Step 1.2: Determine the mainstream of water flow in the rest pool based on the hydrodynamic numerical model.

[0122] In the embodiment of the present invention, the hydrodynamic numerical model in the MIKE software can be used to determine the flow velocity distribution diagram and the flow velocity vector diagram in the rest pool, and the mainstream and backflow of the water flow can be determined based on the flow velocity distribution diagram and the flow velocity vector diagram.

[0123] Step 2, determine whether the boundary of the mainstream intersects with the pool wall. If the boundary of the mainstream intersects with the pool wall of the rest pool, improve the preset structural parameters of the rest pool. If not, the preset structural parameters of the rest pool are the determined fishway rest pool structure.

[0124] In the embodiment of the present invention, in order to obtain the optimal improved structural parameters, a variety of improvement schemes are adopted when improving the structural parameters of the preset resting pool, so as to determine the optimal fishway resting pool structure among the improvement schemes.

[0125] The structural parameters of the preset rest pool are improved, including:

[0126] (a) Obtain the intersection position of the mainstream boundary of the water flow in the rest pool and the pool wall.

[0127] In the embodiment of the present invention, the mainstream boundary of the water flow may intersect with the pool wall at one point or at a continuous area.

[0128] (b) Determine multiple improvement points based on the intersection position, including:

[0129] Get the interval range corresponding to the intersection position;

[0130] The upstream boundary point and midpoint of the interval range are taken as improvement points.

[0131] The improvement points determined by this method have the best improvement effect.

[0132] (c) Rectifier plates are set at the improved points to obtain multiple sets of structural parameters of the improved rest pool, including:

[0133] M sizes of rectifier plates are set at one of the improved points to obtain M groups of improved rest pool structural parameters. This step is repeated until rectifier plates are set at all the improved points to obtain multiple groups of improved rest pool structural parameters.

[0134] Step 3: determine whether the mainstream corresponding to each set of improved structural parameters intersects with the pool wall, and determine the mainstream that does not intersect with the pool wall from the mainstream corresponding to each set of improved structural parameters.

[0135] In the embodiment of the present invention, the mainstream corresponding to the improved structural parameters is determined by step 1.

[0136] Step 4: From the structural parameters corresponding to the disjoint main streams, obtain the structural parameters that meet the preset conditions, and obtain the fishway rest pool structure including:

[0137] (a) Obtain the maximum velocity trajectory of the non-intersecting mainstream, the distribution of the maximum velocity along the path, and the kinetic energy distribution, including:

[0138] A rectangular coordinate system is constructed with the length of the rest pool as the X-axis and the width of the rest pool as the Y-axis;

[0139] On the X-axis, multiple cross sections of the rest pool are intercepted at set intervals;

[0140] Obtain the maximum flow velocity of the non-intersecting mainstreams in each cross section and their corresponding positions;

[0141] According to the maximum flow velocity and its corresponding position, the maximum flow velocity trajectory line and the distribution of the maximum flow velocity value along the way are constructed.

[0142] The horizontal coordinate of the maximum flow velocity trajectory line is X / L, and the vertical coordinate is Y / B, where X is the horizontal coordinate corresponding to the location of the maximum flow velocity, L is the length of the rest pool, Y is the vertical coordinate corresponding to the location of the maximum flow velocity, and B is the width of the rest pool.

[0143] The horizontal coordinate of the maximum flow velocity along the distribution is X / L, and the vertical coordinate is v / V max Where X is the horizontal coordinate corresponding to the location of the maximum flow velocity, L is the length of the rest pool, v is the maximum flow velocity value in each cross section, V max It is the maximum flow velocity in the rest pool.

[0144] In this embodiment, the kinetic energy distribution of the disjoint mainstreams is obtained, specifically including:

[0145] The average kinetic energy of the non-intersecting main streams is determined according to formula (20):

[0146]

[0147] In the formula, v x To improve the speed of the mainstream x direction, v y To improve the mainstream y-direction speed, v z To improve the vertical velocity of the mainstream, k is the average kinetic energy;

[0148] The distribution amount is determined according to the average kinetic energy, the contour lines of the distribution amount are obtained, and the kinetic energy distribution corresponding to the improved mainstream is obtained.

[0149] In the embodiment of the present invention, the dimensionless quantity k is introduced 0.5 / v max (v max is the maximum flow velocity at the vertical seam, m / s) to characterize the distribution of average kinetic energy in the pool chamber.

[0150] (b) Obtain the hydraulic characteristic parameters of the recirculation zone on both sides of the non-intersecting main stream, including:

[0151] Determine the swimming parameters of the fish object, the swimming parameters including the swimming water layer;

[0152] Determine the height section of the rest pool in terms of altitude according to the swimming water layer;

[0153] Determine the influence domain of the recirculation zone on both sides of the non-intersecting mainstream on the height section, including:

[0154] The influence domain of the recirculation zone on both sides of the non-intersecting main flow is determined according to formula (21):

[0155] D=(hx / L)×(hy / B)

[0156] Wherein, hx is the length of the recirculation zone along the x-axis, hy is the length of the recirculation zone along the y-axis, L is the length of the rest pool, and B is the width of the rest pool.

[0157] (c) According to the maximum flow velocity trajectory, the distribution of the maximum flow velocity along the way, the kinetic energy distribution and the hydraulic characteristic parameters of the recirculation area, the structural parameters that meet the preset conditions are determined to obtain the fishway rest pool structure.

[0158] In a specific embodiment, among multiple non-intersecting main streams, the structural parameters corresponding to the non-intersecting main stream with a relatively centered maximum flow velocity trajectory line, the most reduced maximum flow velocity value along the distribution, a kinetic energy less than a preset kinetic energy threshold, and the closest recirculation areas on both sides of the main stream are used as the structure of the fishway rest pool of the present application.

[0159] Among them, the maximum flow velocity trajectory line is relatively centered, that is, its distance from the right bank and the left bank is greater than the preset threshold or the difference between the distance from the left bank and the right bank is the smallest;

[0160] The maximum flow velocity value is reduced the most along the distribution, that is, the downward slope of the maximum flow velocity curve along the path is the largest; the greater the reduction of the mainstream flow velocity along the path, the better the energy dissipation effect, and thus the more conducive it is to fish upstream migration.

[0161] The ranges of the recirculation zones on both sides of the mainstream are closest, that is, the difference between the influence domains of the recirculation zones on both sides of the mainstream is the smallest.

[0162] A second aspect of the present invention provides a fishway rest pool structure determination system, such as Figure 5 As shown, it includes a first mainstream determination module 101 , an improvement module 102 , a second mainstream determination module 103 and a structure determination module 104 .

[0163] The first mainstream determination module 101 is used to determine the mainstream of the water flow in the rest pool according to the preset structural parameters of the rest pool; the improvement module 102 is used to improve the preset structural parameters of the rest pool when the boundary of the mainstream intersects with the pool wall of the rest pool; the second mainstream determination module 103 is used to determine the mainstream that does not intersect with the pool wall from the mainstream corresponding to each group of improved structural parameters; the structure determination module 104 is used to obtain the structural parameters that meet the preset conditions from the structural parameters corresponding to the non-intersecting mainstreams, and obtain the fishway rest pool structure.

[0164] The present invention utilizes a numerical calculation method to establish a numerical model of a vertical slot fishway rest pool, and proposes an improvement plan for key design parameters of the fishway rest pool according to the influence of the flow field distribution and hydraulic characteristics in the rest pool on the migration of fish, thereby optimizing and adjusting the unfavorable flow field and hydraulic characteristics in the rest pool to improve the water flow conditions in the rest pool, making the recirculation area evenly distributed, which is more conducive to the migration and physical recovery of fish in the rest pool, and better playing the function of the fishway rest pool.

[0165] The present application will be described in detail below with more specific embodiments.

[0166] Huangjin Gorge is located in the canyon section of the Hanjiang River in Yangxian County. Huangjin Gorge is 90 li long, starting from Qingshi Port in the east of Yangxian County in the west, flowing east to Weimen and entering Xixiang County. Huangjin Gorge is divided into big and small gorges. The small gorges are from Qingshi Port to Huanzhu Temple in Xinpu, about 45 li long. About 10 li of them belong to the plain section of the Hanjiang River, and the rest belong to the canyon section. The section between Huanzhu Temple and Weimen is about 30 kilometers, called Huangjin Gorge, also known as the Big Gorge, which is the most famous gorges of the Hanjiang River.

[0167] The section from Yangxian to Weimen is a deep canyon. This section is the largest canyon on the Hanjiang mainstream, with a total length of about 53 kilometers, which can be divided into two sections, upper and lower. The upper section is from Xiaoxiakou in Yangxian to Huanzhu Temple, about 23 kilometers long, called Xiaoxia. After the Hanjiang River enters Xiaoxia, the river suddenly narrows to 200 meters, and the mountains on both sides are 100 to 200 meters higher than the riverbed. The section from Huanzhu Temple to Weimen is about 30 kilometers, called Huangjinxia, ​​also known as Daxia, which is the most famous canyon of the Hanjiang River. Daxia is in the shape of a large yoke, with a water distance of 30 kilometers and a land distance of only 9 kilometers. After the Hanjiang River enters Daxia, the mountains on both sides are 300 to 400 meters higher than the riverbed, the valley slope is 50 to 60 degrees, the narrowest part of the river is only 50 meters, and the difference between the highest and lowest water levels is 24 to 25 meters. There are many dangerous rapids in the river, more than 30 of which are famous, among which Turtle Beach, Cage Beach, and Jinliuzi are the most dangerous. Huangjinxia is the starting point of the "Han River to Wei River" water supply line in Shaanxi Province. The Huangjinxia Hydropower Station is responsible for supplying water to the 800-li Qinchuan Plain.

[0168] Huangjinxia Water Conservancy Project is located in the canyon section of the upper reaches of the Hanjiang River, in Yangxian County, east of the Hanzhong Basin in southern Shaanxi. The Huangjinxia Water Conservancy Project includes two main projects: the project and the Qinling Tunnel Huangsan Section (Huangjinxia-Sanhekou). Huangjinxia Water Conservancy Project has the largest pumping station in Asia, with a total installed capacity of 126,000 kilowatts, a designed flow of 70 cubic meters per second, and a designed head of 106.5 meters. After the completion of the project, it will mainly focus on water supply, with an average water transfer of about 1 billion cubic meters over the years, taking into account power generation and improving water navigation conditions. Qinling Tunnel (Huangsan Section) is the main artery connecting the two heart projects of Huangjinxia and Sanhekou, with a designed flow of 70 cubic meters per second and a total length of 16.5 kilometers.

[0169] The main fish species passing through the Huangjinxia Hydropower Project fishway are black carp, grass carp, silver carp, bighead carp, etc. The main season for fish passing through is from April to July every year. Since black carp often swims in the middle and lower layers of water, grass carp generally likes to live in the middle and lower layers of water, and silver carp and bighead carp are both middle and upper layer fish. Among them, the adaptive flow velocity range of grass carp migration is 0.40-1.00m / s, and the minimum flow velocity threshold that stimulates grass carp migration is 0.20m / s.

[0170] The prototype of the numerical model of this application is the fishway rest pool of the Huangjinxia Hydropower Project. The main fish passing through is grass carp (the adaptive flow velocity range is 0.40-1.00 m / s, and the minimum flow velocity threshold to stimulate grass carp migration is 0.20 m / s), while the migration of other fish species is also taken into consideration.

[0171] The total length of the fishway is about 1,908 meters. It is a concrete structure with partitions with guide plates in the middle, forming 118 pool chambers and 41 rest pools. The pool chamber is 2.0 meters wide and 2.5 meters long, with an aspect ratio of 5:4 and a bottom slope of 1:40; the rest pool is the same width as the pool chamber, 7 meters long, with an aspect ratio of 15:4, a bottom slope of 1:100, and the ratio of the seam width to the pool chamber width is 0.175.

[0172] In order to reduce the impact of boundary conditions on the flow field of the rest pool, this application simulates 3 standard pool chambers upstream, 1 rest pool in the middle, and 3 standard pool chambers downstream. The rest pool in the middle is taken as the research object. The calculation area is shown in Figure 6 .

[0173] The model uses unstructured triangular mesh on the plane, with an average side length of 0.2m, 2948 model meshes, and 1699 mesh nodes. After the division is completed, it is adjusted by post-processing to enhance the rationality of the mesh division in the area. The vertical direction uses orthogonal sigma mesh division and is divided into 5 layers on average. The plane mesh division of the calculation area is as follows Figure 7 shown.

[0174] Considering the connectivity of the water body and the similarity of the numerical simulation, the upstream boundary of the calculation area is set as the flow condition with a flow rate of 1.0m 3 / s; the downstream boundary is set as the water depth condition, the water depth is 3.0m; the top is set as the pressure boundary, the pressure value is one atmosphere; the initial water depth of the calculation domain is given as 3.0m, and the initial flow velocity and turbulent energy are both 0. The dry and wet boundaries use the software default values; the model is started statically.

[0175] In order to fully and accurately understand the flow field characteristics inside the rest pool, it is necessary to analyze the water flow structure of the rest pool in the original design through a numerical model, and then propose an improved plan to produce the best fish passing effect.

[0176] In the design of fishway engineering, water depth and water level are key parameters. Water depth affects the flow velocity in the rest pool; water level determines whether the design height of the fishway side wall is safe and whether the water flow can be maintained when the fishway flows. The plane distribution of the water depth and water level contour lines in the rest pool is shown in Figure 8 and Fig. 9 shown.

[0177] pass Figure 8 It can be found that the depth contour lines in the rest pool are sparsely distributed in the rest pool and densely distributed in the vertical seams. Due to the existence of the bottom slope, the depth contour lines are basically perpendicular to the direction of the fishway in the left recirculation area, and the water depth gradually decreases; while in the right mainstream area, the distance between the contour lines is significantly smaller than that in the recirculation area, which indicates that the water depth change in the mainstream area is more drastic than that in the recirculation area.

[0178] pass Fig. 9 It can be seen that the baffles in the vertical seam fishway have a significant water blocking effect. The water level contour lines in the rest pool are sparse, and the water level is approximately at the same elevation. In the vertical seam, the water level contour lines are denser than other positions, indicating that the water level here is drastic, showing obvious weir flow characteristics. In summary, in this fish passage facility, except for the obvious change of water level at the vertical seam, the water level in the rest pool is close to horizontal and the water surface is stable, which is conducive to the passage of fish.

[0179] The flow velocity in the rest pool has a crucial impact on the migration of fish. S. Wu and Liu Min et al. studied the effect of the bottom slope of the fishway on the hydraulic characteristics of the water flow in the fishway through model experiments. They found that when the bottom slope is less than or equal to 5%, the water flow in the rest pool shows obvious two-dimensional distribution characteristics; and the water flow pattern in the pool can be divided into the mainstream area and the return area. The maximum bottom slope of the fishway in the Huangjinxia Hydropower Project is 2.5%, and the bottom slope of the rest pool is 1%, which is much less than 5%. Therefore, the flow velocity distribution in the rest pool can be studied on a two-dimensional level.

[0180] After software calculation, the velocity distribution and velocity vector in the rest pool are obtained as follows: Fig.10 and Fig.11 shown.

[0181] Depend on Fig.10 and Fig.11 It can be found that due to the long length of the rest pool, the mainstream fully spreads to the right bank and hits the wall on the right bank, and then the mainstream deflects and flows to the downstream vertical seam. The rest pool forms a recirculation zone with a lower flow rate at the corners of the left and right banks. There are three recirculation zones in total, but the recirculation zone at the upstream corner is smaller. There is a large recirculation zone on the left side of the mainstream, which accounts for about 46% of the area of ​​the rest pool; the flow arrows in the mainstream area are dense and long, indicating that the flow rate in the mainstream area of ​​the vertical seam jet is larger, while the water flow in the recirculation zone is slower, providing more leisure places for fish during their migration. The maximum flow rate in the rest pool is 1.04m / s, which is lower than the sudden flow rate of 1.19m / s. It is located at the vertical seams on both sides of the rest pool. The flow rate in the mainstream area of ​​the pool is 0.24-0.8m / s, which is lower than the critical flow rate of 0.84m / s for grass carp fry; and the flow rate in the recirculation zone is less than 0.24m / s, which allows the fish to recover their physical strength better in the rest pool. In summary, there are sufficient low-velocity return areas in the rest pool for fish to rest during their migration, but the flow state of the mainstream hitting the wall will affect the upstream efficiency of fish.

[0182] In order to further analyze the flow field distribution in the rest pool, the embodiment of the present invention quantifies the flow velocity distribution in the rest pool. Near the bottom and surface of the pool, the water flow is easily affected by the boundary layer, the flow state is not stable enough, and the fish prefer the middle layer. Therefore, this section takes the cross section of h / H=0.5 (where h is the depth to be studied and H is the water depth), with the guide plate ( Figure 6 The intersection of the side wall and the water-facing surface of the guide plate is the zero point, the direction pointing to the downstream guide plate is the positive direction of the X axis, and the direction pointing to the partition ( Figure 6 The L-shaped plate, the guide plate and the partition together form a vertical slit) direction is the positive direction of the Y axis. In order to study the maximum velocity trajectory of the mainstream area of ​​the rest pool, a cross section is cut every 0.5m from the X-axis square, for a total of 16 sections. The maximum velocity and its location are selected from each cross section, and the maximum velocity of each section is recorded as v i (i=1,2,…,16), and make it dimensionless v i / V max , where V max is the maximum flow velocity in the rest pool. i The X and Y coordinates x and y of the location are converted into dimensionless values ​​x i / L,y i / B, where the basic dimension L is the length of the rest pool, B is the width of the rest pool, L = 3.75B. The maximum velocity trajectory line x in the mainstream area i / L~y i / BSee Fig.12 , the maximum velocity value along the distribution v i / V max ~x i / LSee Fig.13 .

[0183] from Fig.12 It can be seen that the maximum flow velocity trajectory line diagram of the rest pool is basically consistent with the water flow velocity vector diagram. The mainstream first deviates to the left from the vertical seam position. When X / L=0.13, the mainstream hits the wall and begins to flow along the wall. After X / L=0.5, the mainstream gradually deviates to the right until X / L=0.93, when the mainstream begins to deviate to the vertical seam of the next pool.

[0184] And from Fig.13 It can be seen that when X / L is less than 0.1, the maximum velocity of the mainstream in the rest pool decreases rapidly along the way, but when 0.1 is less than X / L is less than 0.4 and 0.6 is less than X / L is less than 0.9, the maximum velocity of the mainstream decreases along the way. When 0.4 is less than X / L is less than 0.6, the maximum velocity of the mainstream gradually decreases along the way. When X / L is greater than 0.9, the maximum velocity increases rapidly along the way. Obviously, the closer to the vertical seam, the more drastic the change in the maximum velocity of the mainstream. The change in velocity along the maximum velocity trajectory line can reflect the head loss along the way in the pool to a certain extent. It can be generally believed that the more the mainstream velocity is reduced along the way, the better the energy dissipation effect, which is more conducive to the upstream migration of fish.

[0185] The presence of water-blocking facilities in the vertical seam fishway creates a flow area in the fishway pool with a lower flow velocity than that in the vertical seam. When the vertical seam jet enters the pool with a lower flow velocity, due to the mixing effect of the water flow, part of the kinetic energy of the water flow is converted into heat energy and dissipated, reducing the energy of the water flow and making it easier for fish to swim upstream.

[0186] Kinetic energy is an important hydrodynamic factor that describes turbulence. Controlling the magnitude of this factor in the fish passage is of great significance to the upstream migration of fish. An important feature of the velocity field is the average kinetic energy per unit mass, k, which is defined as:

[0187]

[0188] Where: v x 、v y and v z They are the average longitudinal, average transverse and vertical velocities respectively, in m / s.

[0189] Here we introduce the dimensionless quantity k 0.5 / v max (v max is the maximum flow velocity at the vertical seam, m / s) to characterize the distribution of the average kinetic energy in the pool. Its contour distribution is shown in Fig.14 shown.

[0190] Depend on Fig.14 It can be seen that k is formed in the rest pool 0.5 / v maxThe kinetic energy band is greater than 0.2, and the kinetic energy decreases along the way within this range, indicating that the vertical seam jet energy is gradually dissipated in the rest pool, and the kinetic energy gradually decreases. The rest pool is divided into two low kinetic energy zones of different sizes on both sides of the high kinetic energy area, and the kinetic energy at the vertical seam is the largest, with a dimensionless kinetic energy value of about 0.7. In summary, under the existing design scheme, the kinetic energy in the jet zone continues to decay, and the dimensionless kinetic energy k at the vertical seam is 0.5 / v max When the maximum value is reached, the kinetic energy in the recirculation zone is at a lower level, while in the low kinetic energy zone, fish migration saves more energy and takes less time to pass. Under this scheme, except for a small area of ​​high kinetic energy, the dimensionless kinetic energy value of most areas in the rest pool is below 0.4, which can meet the requirements of fish resting and migrating in the rest pool.

[0191] After analyzing the numerical simulation results of the original design scheme, it is found that there are unfavorable flow patterns in the rest pool, such as the mainstream hitting the wall and sticking to the wall, which will affect the migration of fish. This application will be based on the original design scheme, and its structure and design parameters will be locally optimized and adjusted to design different schemes to improve the hydrodynamic conditions in the rest pool and make it more suitable for the migration of target fish.

[0192] Through the analysis of the calculation results of the original design scheme, it was determined to make partial modifications to the preliminary design scheme. The specific design method is as follows.

[0193] Option 1: Add a rectifier plate 0.6 meters long and 0.2 meters wide on the right bank of the rest pool, 1 meter away from the upstream pier (the boundary of the intersection).

[0194] Option 2: Add a rectifier plate 0.6 meters long and 0.2 meters wide on the right bank of the rest pool, 2 meters away from the upstream pier (center of the intersection).

[0195] Option 3: Add a rectifier plate 0.5 meters long and 0.2 meters wide on the right bank of the rest pool, 1 meter away from the upstream pier.

[0196] Option 4: Add a rectifier plate 0.4 meters long and 0.2 meters wide on the right bank of the rest pool, 1 meter away from the upstream pier.

[0197] Option 5: Add a rectifier plate 0.4 meters long and 0.2 meters wide on the right bank of the rest pool, 1.5 meters away from the upstream pier.

[0198] In the optimization scheme, only the partial modification of the fish-passing facilities was made. The numerical simulation of different schemes of the fish-passing facilities was carried out with the help of MIKE 3 FM. The unstructured grid was generated using Mesh Generator. The values ​​of other calculation parameters were consistent with those of the original scheme. The velocity vector diagrams in the rest pool under different schemes are shown in Figure 2. Fig.15 shown.

[0199] Depend on Fig.15 It can be seen that only adding a rectifier has little effect on the flow velocity at the vertical joint, and the maximum flow velocity remains basically unchanged. Schemes 1, 2, 3, and 5 add rectifiers, which significantly inhibit the continuous development of the mainstream to the right bank, so that the mainstream turns in time and approaches or even gets close to the left bank, increasing the area of ​​the recirculation zone on the right bank, while reducing the area of ​​the recirculation zone behind the left pier; however, Scheme 4 fails to inhibit the development of the mainstream to the right bank in time due to the reduction of the length of the rectifier, and only delays the position where the mainstream hits the wall on the right bank. In summary, Schemes 1, 2, 3, and 5 improve the distribution of the water flow field in the rest pool, avoid the mainstream directly impacting the right bank to a certain extent, and retain a large area of ​​low-speed recirculation zone in the rest pool.

[0200] The maximum velocity trajectory x in the mainstream area under each scheme i / L~y i / BSee Fig.16 , the maximum velocity value along the distribution v i / V max ~x i / LSee Fig.17 .

[0201] Depend on Fig.16 It can be seen that the mainstream of the original scheme and scheme 4 is mainly distributed on the right bank, while the mainstream of schemes 1, 2, 3, and 5 is distributed on the left bank. It can be clearly felt that the rectifier has a guiding effect on the mainstream, which is consistent with the previous conclusion. Fig.17 It can be found that the maximum flow velocity in the rest pool of each scheme is highly uniform in the areas of X / L<0.1 and X / L>0.9. This is because the water flow characteristics are seriously affected by the vertical seam jet near the vertical seam of the rest pool, and the structure inside the rest pool has limited impact on it. In the area of ​​0.1<X / L<0.9, the maximum flow velocity of each scheme gradually decreases along the way, among which Scheme 3 decreases rapidly, reflecting the better energy dissipation effect of this scheme.

[0202] The recirculation zone of the rest pool on the h / H=0.5 section is taken as the research object, the length of the recirculation zone along the X-axis direction is taken as hx, and the length along the Y-axis direction is taken as hy, and they are converted into dimensionless steel values ​​hx / L and hy / B. At the same time, the shape ratio of the recirculation zone of the rest pool is defined as hx / hy, and the influence domain of the recirculation zone of the rest pool is defined as (hx / L) ×(hy / B). The corresponding values ​​of each scheme on the recirculation zone h / H=0.5 section are listed in Table 1.

[0203] Table 1 Hydraulic characteristic parameters of the recirculation zone

[0204]

[0205]

[0206] It can be seen from Table 1 that in the rest pool under each design scheme, the dimensionless length hx / L of the recirculation zone in the X-axis direction is in the range of 0.23-0.79, the hy / B in the Y-axis direction is in the range of 0.35-0.61, the influence domain of the recirculation zone (hx / L)×(hy / B) is less than 0.46, and the shape ratio of the recirculation zone is in the range of 1.62-7.67. The calculation results show that when scheme 3 is adopted, the recirculation zone ranges on both sides of the mainstream are the closest, the water flow structure is the most reasonable, and the flow velocity in the recirculation zone is less than 0.3m / s. The influence domain of the recirculation zone on the left side accounts for 36% of the rest pool, and the right side accounts for 19%, which is most suitable for fish to go upstream and downstream.

[0207] Calculate the average flow kinetic energy k in the rest pool, using the maximum flow velocity v at the vertical seam max The root mean square of the average flow kinetic energy is dimensionlessly processed to obtain the k in the rest pool: 0.5 / v max Contour map Fig.18 shown.

[0208] It can be seen from the contour map that the ratio of the root mean square value of the average kinetic energy in the mainstream area of ​​the rest pool to the maximum flow velocity of the vertical seam is mostly above 0.4, while in the recirculation area, its value is below 0.2. The kinetic energy distribution of different schemes is studied as follows:

[0209] Original solution dimensionless kinetic energy k 0.5 / v max The area above 0.4 accounts for about 40% of the mainstream area; while in Schemes 1 and 2, k 0.5 / v max The area with k > 0.4 increases significantly. 0.5 / v max The value of k reflects the kinetic energy in the region: 0.5 / v max The larger the value, the stronger the kinetic energy of the water flow and the smaller the kinetic energy dissipation; conversely, the smaller the value, the smaller the kinetic energy of the water flow and the stronger the kinetic energy dissipation. 0.5 / v max The area with a value greater than 0.4 is smaller than the original solution, where k 0.5 / v max The area with >0.4 is about 25% of the mainstream area. It can be seen that from the perspective of kinetic energy distribution, Schemes 3, 4 and 5 are better than the original scheme, and Scheme 3 is the best, while Schemes 1 and 2 are worse than the original scheme.

[0210] In summary, the optimization schemes are effective in preventing the vertical seam jet from directly impacting the right bank, but Scheme 4 can only delay the jet impact. As the jet continues to extend, it still hits the wall. Schemes 1 and 2 will increase the kinetic energy of the water in the rest pool and reduce the kinetic energy dissipation, which is not conducive to the upstream migration of fish. After analyzing the area and distribution position of the recirculation zone, Scheme 3 can make the recirculation area on both sides of the mainstream area closer and the water flow structure more reasonable. Taking into account the pros and cons of each scheme, it is finally believed that Scheme 3 can best meet the migration needs of fish in the rest pool.

[0211] This application is based on the Huangjinxia Water Conservancy Hub fishway rest pool, and uses MIKE software to model and calculate the existing design scheme. Through the research and analysis of the calculation results of the existing design scheme, it is found that there are problems in the existing design scheme, so different optimization design schemes are proposed. By comparing the pros and cons of the hydrodynamic conditions in the rest pool under different design schemes, the most favorable fish passage scheme for the target fish migration is selected.

[0212] This application analyzes the numerical calculation results of the existing design scheme and believes that the water surface in the rest pool is stable, and the water flow spreads from the mainstream area to both sides along the way, mainly concentrated on the right side of the rest pool, and forms a large recirculation area on the left side. The mainstream directly hits the right wall from the vertical seam and runs along the wall, making the recirculation area unevenly distributed, which is not conducive to the migration and physical recovery of fish in the rest pool, and needs to be modified and optimized.

[0213] The addition of a rectifying plate in the present application can effectively improve the flow pattern of the mainstream adhering to the wall in the rest pool, thereby forming flow characteristics that are conducive to the upstream migration of migratory fish.

[0214] Each optimized design scheme of the present application is effective in preventing the vertical slit jet from directly impacting the right wall, but Scheme 4 can only delay the jet impact, and as the jet continues to extend, it still hits the wall; and Schemes 1 and 2 will increase the kinetic energy of the water in the rest pool and reduce the kinetic energy dissipation, which is not conducive to the upstream migration of fish. After analyzing the area and distribution position of the recirculation zone, Scheme 3 can make the recirculation zone areas on both sides of the mainstream area closer and the water flow structure more reasonable. Taking into account the pros and cons of each scheme, it is finally believed that Scheme 3 can best meet the migration needs of fish in the rest pool.

[0215] The above are only a few embodiments of the present application and do not constitute any form of limitation to the present application. Although the present application is disclosed as above with preferred embodiments, it is not intended to limit the present application. Any technician familiar with the profession, without departing from the scope of the technical solution of the present application, using the technical content disclosed above to make slight changes or modifications are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A method for determining the structure of a fishway rest pool, characterized in that: include: Step 1: determining the main flow of water in the rest pool according to the preset structural parameters of the rest pool; Step 2: if the boundary of the main flow intersects with the wall of the rest pool, then improving the structural parameters of the preset rest pool; Step 3, determining the mainstream that does not intersect with the pool wall from the mainstreams corresponding to each set of improved structural parameters; Step 4: obtaining structural parameters that meet preset conditions from the structural parameters corresponding to the disjoint main streams, and obtaining the fishway rest pool structure, including: Obtaining the maximum flow velocity trajectory, the distribution of the maximum flow velocity value along the path, and the kinetic energy distribution of the non-intersecting mainstream; Obtaining hydraulic characteristic parameters of the recirculation zones on both sides of the non-intersecting main streams; According to the maximum flow velocity trajectory, the distribution of the maximum flow velocity along the path, the kinetic energy distribution and the hydraulic characteristic parameters of the recirculation zone, the structural parameters meeting the preset conditions are determined to obtain the fishway rest pool structure; The hydraulic characteristic parameters of the recirculation areas on both sides of the non-intersecting main streams are obtained, specifically including: Determining swimming parameters of the fish object, wherein the swimming parameters include a swimming water layer; Determine the height cross section of the rest pool in height according to the swimming water layer; Determine the influence domain of the recirculation zone on both sides of the non-intersecting main flow on the height cross section; Improving the structural parameters of the preset rest pool specifically includes: Obtaining the intersection position of the boundary of the mainstream in the rest pool and the pool wall; Determine a plurality of improvement points according to the intersection positions; A rectifier plate is arranged at the improved point to obtain multiple sets of structural parameters of the improved rest pool; According to the intersection position, multiple improvement points are determined, including: Obtaining the interval range corresponding to the intersection position; The upstream boundary point and the midpoint of the interval range are used as improvement points.

2. The method for determining the structure of a fishway resting pool according to claim 1, characterized in that: Rectifier plates are arranged at the improved points to obtain multiple sets of improved structural parameters of the rest pool, including: M sizes of rectifier plates are set at one of the improved points to obtain M groups of improved rest pool structural parameters, and this step is repeated until rectifier plates are set at all improved points to obtain multiple groups of improved rest pool structural parameters.

3. The method for determining the structure of a fishway resting pool according to claim 1, characterized in that: Obtaining the maximum flow velocity trajectory line and the distribution of the maximum flow velocity value along the non-intersecting mainstream specifically includes: A rectangular coordinate system is constructed with the length direction of the rest pool as the X-axis and the width direction of the rest pool as the Y-axis; On the X-axis, multiple cross sections of the rest pool are intercepted at set intervals; Obtaining the maximum flow velocity of the non-intersecting mainstreams in each of the cross sections and their corresponding positions; According to the maximum flow velocity value and its corresponding position, a maximum flow velocity trajectory line and the distribution of the maximum flow velocity value along the path are constructed.

4. The method for determining the structure of a fishway resting pool according to claim 1, characterized in that: Obtaining the kinetic energy distribution of the non-intersecting mainstreams specifically includes: The average kinetic energy of the non-intersecting main streams is determined according to a first formula, wherein the first formula is: ， In the formula, For the improvement of the mainstream The speed of the direction, For the improvement of the mainstream The speed of the direction, To improve the vertical velocity of the mainstream, is the average kinetic energy; The distribution amount is determined according to the average kinetic energy, and the contour lines of the distribution amount are obtained to obtain the kinetic energy distribution of the non-intersecting mainstreams.

5. The method for determining the structure of a fishway resting pool according to claim 1, characterized in that: Determining the influence domain of the recirculation zone on both sides of the non-intersecting mainstream on the height cross section specifically includes: The influence domain of the recirculation zone on both sides of the non-intersecting mainstream on the height cross section is determined according to the second formula, and the second formula is: ， In the formula, The edge of the recirculation zone The length in the axial direction, The edge of the recirculation zone The length in the axial direction, is the length of the rest pool, is the width of the rest pool.

6. A fishway rest pool structure determination system based on the fishway rest pool structure determination method according to any one of claims 1 to 5, characterized in that: include: A first mainstream determination module, the mainstream determination module is used to determine the mainstream of the water flow in the rest pool according to preset structural parameters of the rest pool; An improvement module, wherein the improvement module is used to improve the structural parameters of the preset rest pool when the boundary of the main flow intersects with the pool wall of the rest pool; A second mainstream determination module, the second mainstream determination module is used to determine the mainstream that does not intersect with the pool wall from the mainstreams corresponding to each group of improved structural parameters; A structure determination module is used to obtain structural parameters that meet preset conditions from the structural parameters corresponding to the non-intersecting main streams to obtain the fishway rest pool structure.

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