Inwardly concave shaped stilling basin

Abstract

The application discloses a concave-shaped special-shaped stilling basin and belongs to the technical field of flood discharge and energy dissipation in water conservancy and hydropower engineering, and solves the problem of insufficient energy dissipation of the existing stilling basin. The technical scheme is as follows: the concave-shaped special-shaped stilling basin, the side walls of the four sides of the stilling basin are respectively an upper side wall on the upstream side, a lower side wall on the downstream side, a left side wall on the left bank side and a right side wall on the right bank side, the top of the upper side wall is a differential type flip bucket, the upper side wall, the left side wall and the right side wall are all provided with at least one A-shaped groove which is respectively convex to the upstream direction, the left bank direction and the right bank direction, the top of the lower side wall is provided with a water outlet inclined surface which is inclined upward along the water flow direction, the lower side wall is further provided with at least one B-shaped groove which is convex to the downstream direction, and the drop area of the bottom plate of the stilling basin is provided with at least one C-shaped groove. The application weakens the water flow energy in the stilling basin, reduces the bottom plate pulsation pressure and the bottom flow velocity, reduces the scouring effect of the water flow, eliminates the secondary water jump of the water flow out of the stilling basin and the uneven transverse impact water flow and the like.

Description

Technical Field

[0001] This invention belongs to the field of flood discharge and energy dissipation technology in water conservancy and hydropower engineering, specifically a concave irregular-shaped energy dissipation pool. Background Technology

[0002] The structural layout and energy dissipation methods of spillway structures are crucial for ensuring the safe operation of water conservancy projects and preventing scouring of downstream river channels, representing a significant portion of investment. With increasing attention to environmental impact during the construction of water conservancy and hydropower projects, bottom flow energy dissipation, as one of the current mainstream energy dissipation methods, is favored for its effective mitigation of atomization problems caused by high-speed water flow during flood discharge. Traditional stilling basins suffer from poor inflow conditions, resulting in poor flow patterns and high flow velocities. This prevents sufficient hydraulic jumps and collisions, hindering rapid energy reduction and leading to inadequate energy dissipation. During flood discharge, excessive near-bottom velocity and turbulent flow patterns often occur, potentially causing bottom instability, scouring, and cavitation damage, thus affecting structural safety. Only by addressing the shortcomings of bottom flow energy dissipation in high-head projects while leveraging its environmental advantages during flood discharge can it be better applied to a wide range of water conservancy projects. Summary of the Invention

[0003] This invention provides a concave irregular-shaped stilling basin, which solves the problem of insufficient energy dissipation in existing stilling basins.

[0004] The technical solution adopted in this invention is: a concave irregular-shaped stilling basin, the side walls of the stilling basin are the upper side wall on the upstream side, the lower side wall on the downstream side, the left side wall on the left bank side and the right side wall on the right bank side, the top of the upper side wall is a sill, the sill is a differential sill, the sill is a horizontal section and an arc section along the water flow direction, and the horizontal section and the arc section are tangent.

[0005] The upper, left, and right walls are each provided with at least one level of A-shaped grooves protruding towards the upstream, left bank, and right bank directions, respectively. The number of A-shaped grooves on the upper, left, and right walls is equal and corresponds one-to-one. The centerline of the A-shaped grooves is horizontal, and the two ends of the A-shaped grooves extend to the ends of the side walls. The three surfaces of the A-shaped groove from top to bottom are the upper surface, the bottom surface, and the lower surface. The dihedral angle formed by the upper surface and the bottom surface is an obtuse angle. The intersection of the upper surface and the bottom surface is horizontal, the bottom surface is vertical, and the lower surface is horizontal. On the vertical section perpendicular to the centerline of the A-shaped groove, the projection of the upper surface on the horizontal plane is shorter than that of the lower surface on the horizontal plane. The upper surface of the highest A-shaped groove is connected to the end of the cantilever sill by a vertical transition surface. The lower surface of the lowest A-shaped groove is the bottom plate of the stilling basin or the bottom surface of the C-shaped groove. When there are two or more levels of A-shaped grooves, adjacent A-shaped grooves are connected by a vertical transition surface.

[0006] The top of the lower wall is provided with an upward-sloping outlet surface along the water flow direction. The lower wall is also provided with at least one B-shaped groove protruding downstream. The center line of the B-shaped groove is horizontal, and the two ends of the B-shaped groove extend to the ends of the side wall. The three sides of the B-shaped groove from top to bottom are the upper side, the bottom side, and the lower side. The dihedral angle formed by the upper side and the bottom side is an obtuse angle, and the intersection line of the upper side and the bottom side is horizontal. The bottom side is vertical, and the dihedral angle formed by the bottom side and the lower side is an obtuse angle. The intersection line of the bottom side and the lower side is horizontal. The upper side of the highest B-shaped groove is connected to the outlet slope through a vertical transition surface. The dihedral angle formed by the lower side of the lowest B-shaped groove and the bottom plate of the stilling basin is an obtuse angle. When there are two or more B-shaped grooves, the adjacent B-shaped grooves are connected by a vertical transition surface.

[0007] The bottom slab of the stilling basin is provided with at least one level of C-shaped grooves in the water-receiving area. The center line of the C-shaped grooves is horizontal and points to the left bank and the right bank respectively. The two ends of the C-shaped grooves extend to the left wall and the right wall respectively. Both sides of the C-shaped grooves are vertical and the bottom surface of the C-shaped grooves is horizontal. When there are two or more levels of C-shaped grooves, each level of C-shaped grooves is stepped, and the depth of each level of C-shaped groove relative to the bottom slab of the stilling basin gradually increases from upstream to downstream.

[0008] To optimize the position and state of water flow entering the stilling basin, further details are provided: the angle α of the sill is 30°–45°, and the radius of the arc segment is... R ≥ The length of the horizontal section of the embankment along the direction of water flow. L1 = (0.3~0.4) R , ,in: The velocity of the water flowing into the embankment; D 1 The critical water depth for water to enter the embankment; a characteristic depth used to characterize the cross-section of the water flow. , denoted as denoted by , where is the unit width flow rate of the water entering the sill; g is the acceleration due to gravity.

[0009] To further enhance the energy dissipation of the water flow within the stilling basin and reduce the scouring effect of the water flow on the side walls of the stilling basin, at least two levels of A-shaped grooves are provided on the upper, left, and right side walls. The heights of the transition surfaces on the upper, left, and right side walls are equal, and the dihedral angles formed by the upper and lower surfaces of each level of A-shaped groove are equal.

[0010] Furthermore, the height h1 of the transition surface between the upper, left, and right walls is 1 / 4 to 1 / 3 of the height h2 of the bottom surface of the A-shaped groove; the dihedral angle β formed by the upper side and bottom surface of the A-shaped groove is 115° to 130°; and the distance from the lower side of the highest A-shaped groove to the vertical section perpendicular to the centerline of the A-shaped groove is... d1 4 / 3Rsinα, where R is the radius of the arc segment of the cantilever, and α is the cantilever angle; the distance from the lower side of the lowest A-shaped groove located on the upper wall to the vertical section perpendicular to the centerline of the A-shaped groove. d2 It is 1 / 3 of the length L of the stilling basin, where the length L is the distance from the bottom plate of the stilling basin along the upstream to the downstream direction.

[0011] Furthermore, on the vertical section of the center line of the B-type groove, the projection of the upper side of the same level B-type groove on the horizontal plane is shorter than the projection of the lower side on the horizontal plane. The line segment corresponding to the upper side of the highest B-type groove is symmetrically arranged with the line segment corresponding to the water outlet slope. The axis of symmetry passes through the midpoint of the line segment corresponding to the highest transition surface located on the lower side wall, and the axis of symmetry is horizontal.

[0012] Specifically: the height h3 of the transition surface located on the lower wall and at the highest position is equal to the height h4 of the bottom surface of the B-type groove, and the dihedral angle γ formed by the lower side of the lowest B-type groove and the bottom plate of the stilling basin is 135° to 180°.

[0013] Specifically: Type B groove is the first level, and the height h5 of the lower side of Type B groove is 1 / 3 of the depth H of the stilling basin. The depth H of the stilling basin is the height difference between the bottom plate of the stilling basin and the horizontal section of the sill.

[0014] To further optimize the flow pattern of water after it falls into the stilling basin, the following is further proposed: at least two levels of C-shaped grooves, each level of C-shaped groove is stepped, the step height of each level of step is equal, and the step width of each level of step is equal.

[0015] Specifically: the step height h6 of each level of the steps is 1 / 6 to 1 / 4 of the stilling basin depth H, and the stilling basin depth H is the height difference between the bottom plate of the stilling basin and the horizontal section of the sill.

[0016] Specifically: the sum of the tread widths d3 of each level of the steps is 1 / 3 of the length L of the stilling basin.

[0017] The beneficial effects of this invention are as follows: The top of the upper wall on the upstream side of the stilling basin is a differential sill. Water flows over the sill, forming multiple multi-layered water jets with distinct distributions, which then fall into the stilling basin. The longitudinal velocity gradient causes the water flowing into the stilling basin to diffuse laterally, increasing the area of ​​the water jets, enhancing lateral turbulent dissipation, reducing the flow velocity, and weakening the impact of the water flow on the bottom plate of the stilling basin. After falling into the stilling basin, the lateral diffusion of the water flow triggers a three-dimensional hydraulic jump, intensifying the collision between adjacent water jets, and rapidly reducing the flow velocity. The C-shaped groove intensifies the swirling turbulence of the water flowing into the stilling basin on both the upstream and downstream sides, enhancing energy dissipation, significantly reducing the pulsating pressure on the bottom plate and the near-bottom flow velocity, ensuring the safe operation of the stilling basin. Part of the water flowing into the stilling basin rolls upstream into the A-shaped groove on the upper wall, triggering shear friction, increasing energy dissipation within the stilling basin, and reducing the scouring effect of the water flow. The A-shaped grooves on the left and right walls increase the contact area of ​​the water flow, significantly increasing the concentration and scale of air mixing in the stilling basin. The A-shaped grooves on the upper, left, and right walls, together with the B-shaped groove on the lower wall, create large-scale backflow and local vertical vortices in the stilling basin, enhancing energy shear turbulence dissipation and velocity attenuation. This adjusts the flow pattern of the water flowing out of the stilling basin and significantly eliminates phenomena such as secondary hydraulic jumps and uneven lateral deflection of the water flowing out of the stilling basin. Attached Figure Description

[0018] Figure 1 This is a schematic plan view of an embodiment of the concave irregular-shaped stilling basin of the present invention.

[0019] Figure 2 yes Figure 1 Vertical cross-section along the AA direction.

[0020] Figure 3 yes Figure 1 Vertical cross-section along the BB direction.

[0021] Attached diagram labels: Left wall 1, Right wall 2, Sill 3, Type A groove 4, Base plate 5, Water outlet slope 6, Type B groove 7, Type C groove 8. Detailed Implementation

[0022] The invention will now be further described with reference to the accompanying drawings.

[0023] See Figures 1-3This invention relates to a concave, irregularly shaped stilling basin. The stilling basin is quadrilateral in shape, with its four side walls being the upper side wall on the upstream side, the lower side wall on the downstream side, the left side wall 1 on the left bank, and the right side wall 2 on the right bank. The top of the upper side wall is a differential sill 3, which consists of a horizontal section and an arc section along the water flow direction, with the horizontal and arc sections tangent to each other. The sill 3 is also located at the bottom of the spillway. To optimize the position and state of water flow entering the stilling basin, the sill angle α of the sill 3 is 30°–45°, and the radius of the arc section is… R ≥ , ,in: The velocity of the water flowing into the sill 3; D 1 The critical water depth for water to enter the sill 3 is used to characterize the characteristic depth of the water flow across the cross section. , The unit width flow rate of the water entering the sluice gate 3; g is the acceleration due to gravity; additionally, the length of the horizontal section of the sluice gate 3 along the direction of water flow. L1 Generally (0.3~0.4) R .

[0024] The length L, depth H, and width of the stilling basin are determined according to the traditional stilling basin calculation method. The width of the stilling basin is related to the width of the river channel. The length L is the distance from the bottom plate 5 of the stilling basin to the downstream direction. The depth H is the height difference between the bottom plate 5 of the stilling basin and the horizontal section of the embankment 3.

[0025] To optimize the flow direction and flow pattern of water entering the stilling basin, at least one level of A-shaped grooves 4 are provided on the upper wall, left wall 1, and right wall 2, respectively convex towards the upstream, left bank, and right bank directions. The number of A-shaped grooves 4 on the upper wall, left wall 1, and right wall 2 is equal and corresponds one-to-one. The centerline of the A-shaped grooves 4 is horizontal, so A-shaped grooves 4 of the same level refer to A-shaped grooves 4 located at the same height. The dimensions of each A-shaped groove 4 are consistent at any position, and the shape and size of A-shaped grooves 4 of the same level are consistent. The two ends of the A-shaped grooves 4 extend to the ends of the side walls. For A-shaped grooves 4 of the same level, the A-shaped grooves 4 of the left wall 1 and right wall 2 are connected to the A-shaped grooves 4 of the upper wall. The three surfaces of the A-shaped groove 4 are defined as the upper side, bottom surface, and lower side surface from top to bottom. The dihedral angle formed by the upper side surface and the bottom surface is an obtuse angle, denoted as β. The intersection of the upper side surface and the bottom surface is horizontal, the bottom surface is vertical, and the lower side surface is horizontal. For example, the dihedral angle β formed by the upper side and bottom surface of the A-type groove 4 is 115° to 130°. On a vertical section perpendicular to the centerline of the A-type groove 4, the projection of the upper side onto the horizontal plane is shorter than the projection of the lower side onto the horizontal plane. The upper side of the highest-positioned A-type groove 4 is connected to the end of the cantilever 3 via a vertical transition surface. The lower side of the lowest-positioned A-type groove 4 is the bottom plate 5 of the stilling basin or the bottom surface of the C-type groove 8. For the A-type groove 4 located on the upper side and at the lowest position, the lower side is the bottom plate 5 of the stilling basin; for the A-type groove 4 located on the lower side and at the lowest position, the lower side is partially the bottom plate 5 of the stilling basin and partially the bottom surface of the C-type groove 8. When the A-type groove 4 has two or more levels, adjacent A-type grooves 4 are connected by a vertical transition surface. To maximize energy dissipation within the stilling basin and reduce scouring effects on its sidewalls, at least two levels of A-shaped grooves 4 are provided on the upper sidewall, left sidewall 1, and right sidewall 2. The height of each transition surface on these surfaces is equal, denoted as h1. The dihedral angle formed by the upper side and bottom surface of each level of A-shaped groove 4 is equal, denoted as β. Generally, the height h1 of the transition surface on the upper sidewall, left sidewall 1, and right sidewall 2 is 1 / 4 to 1 / 3 of the height h2 of the bottom surface of the A-shaped groove 4, i.e., h1 = (1 / 4 to 1 / 3)h2. The distance from the lower side of the highest A-shaped groove 4 to the vertical section perpendicular to the centerline of the A-shaped groove 4 is... d1 4 / 3Rsinα; the distance on the vertical section perpendicular to the centerline of the A-type groove 4, located on the upper wall and at the lowest position. d2 It is 1 / 3 of the length L of the stilling basin.

[0026] The top of the lower wall is provided with an upward-sloping outlet ramp 6 along the water flow direction, which serves as a channel for water to flow out of the stilling basin. The lower wall also has at least one downstream-facing B-shaped groove 7, located below the outlet ramp 6. The centerline of the B-shaped groove 7 is horizontal, and both ends extend to the ends of the side wall. The B-shaped groove 7 is fully, partially, or not connected to the A-shaped grooves 4 located on the left wall 1 and right wall 2. The three surfaces of the B-shaped groove 7 are defined as the upper surface, bottom surface, and lower surface from top to bottom. The dihedral angle formed by the upper surface and the bottom surface is obtuse, and the intersection of the upper surface and the bottom surface is horizontal. The bottom surface is vertical, and the dihedral angle formed by the bottom surface and the lower surface is obtuse, and the intersection of the bottom surface and the lower surface is horizontal. When there are two or more B-type grooves 7, adjacent B-type grooves 7 are connected by a vertical transition surface. Specifically, the lower side of the upper B-type groove 7 is connected to the upper side of the lower B-type groove 7 by a vertical transition surface. The upper side of the highest B-type groove 7 is connected to the outlet slope 6 by a vertical transition surface, and the dihedral angle formed between the lower side of the lowest B-type groove 7 and the bottom plate 5 of the stilling basin is an obtuse angle. To optimize the flow pattern of water at different heights, see [reference needed]. Figure 2 On the right side, in the vertical section perpendicular to the center line of the B-type groove 7, the projection of the upper side of the same level B-type groove 7 onto the horizontal plane is shorter than the projection of the lower side onto the horizontal plane. The line segment corresponding to the upper side of the highest B-type groove 7 is symmetrically arranged with the line segment corresponding to the water outlet slope 6. The axis of symmetry is horizontal and passes through the midpoint of the line segment corresponding to the highest transition surface located on the lower wall. Generally, the height h3 of the highest transition surface located on the lower wall is equal to the height h4 of the bottom surface of the B-type groove 7. The dihedral angle γ formed by the lower side of the lowest B-type groove 7 and the bottom plate 5 of the stilling basin is 135° to 180°. For example, referring to 2, the B-type groove 7 is a first-level groove, and the height h5 of the lower side of the B-type groove 7 is 1 / 3 of the depth H of the stilling basin.

[0027] To optimize the direction and flow pattern of water after it enters the stilling basin, at least one level of C-shaped grooves 8 are provided in the water-falling area of ​​the stilling basin's bottom plate 5. The centerlines of the C-shaped grooves 8 are horizontal and point towards the left and right banks respectively. The centerline of the C-shaped grooves 8 is parallel to the centerline of the A-shaped grooves 4 located on the upper sidewall. The two ends of the C-shaped grooves 8 extend to the left side wall 1 and the right side wall 2 respectively. Both sides of the C-shaped grooves 8 are vertical, and these two sides form the two boundaries of the C-shaped grooves 8 along the upstream and downstream directions. These boundaries can be solid structures or non-solid structures. The bottom surface of the C-shaped grooves 8 is horizontal. When there are two or more levels of C-shaped grooves 8, each level of C-shaped groove 8 forms a stepped shape, and the depth of each level of C-shaped groove 8 relative to the bottom plate 5 of the stilling basin gradually increases from upstream to downstream. Considering the location of the water-falling area of ​​the stilling basin, each level of C-shaped groove 8 is generally arranged at the middle 1 / 3 of the stilling basin, such as... Figure 2As shown, the sum of the tread widths d3 of each step is 1 / 3 of the stilling basin length L, and the distance between the C-shaped groove 8 closest to the upper wall and the upper wall is 1 / 3 of the stilling basin length L. When there is only one level of C-shaped groove 8, both sides of the C-shaped groove 8 are vertical and parallel to each other. When there are two or more levels of C-shaped groove 8, each level of C-shaped groove 8 is stepped, and the tread height and tread width of each level are equal. The tread height h6 of each level of step is 1 / 6 to 1 / 4 of the stilling basin depth H, and the stilling basin depth H is the height difference between the bottom plate 5 of the stilling basin and the horizontal section of the cantilever sill 3.

[0028] The differential sill creates multiple, multi-layered water jets with distinct distributions. The longitudinal velocity gradient formed by the C-shaped grooves 8 causes the water flowing into the stilling basin to diffuse laterally, increasing the surface area of ​​the water jets. In the bottom-flow stilling basin, this lateral diffusion induces a ternary hydraulic jump. The continuous arrangement of C-shaped grooves 8 on the stilling basin floor places the ternary hydraulic jump downstream, enhancing lateral turbulent dissipation and intensifying collisions between adjacent water jets. This results in intense turbulence, a rapid decrease in flow velocity and pulsating pressure, and reduced impact on the stilling basin floor. Water flows upstream into the A-shaped grooves 4 on the upper wall, inducing shear friction, increasing energy dissipation within the stilling basin, and mitigating the scouring effect of the water flow. The concave irregular-shaped stilling basin enhances the longitudinal transverse swirling and surface aeration turbulence, while also intensifying the vertical shear swirling and local backflow. This causes the water flow velocity in the stilling basin to decrease rapidly, energy dissipation to be enhanced, and pressure to decrease. The phenomena of secondary hydraulic jump and uneven transverse deflection of the water flowing out of the stilling basin are significantly eliminated, thus improving the energy dissipation rate and reducing problems such as siltation in the stilling basin.

Claims

1. A concave irregular-shaped stilling basin, wherein the side walls on the four sides of the stilling basin are the upper side wall on the upstream side, the lower side wall on the downstream side, the left side wall on the left bank (1), and the right side wall on the right bank (2), characterized in that: The top of the upper wall is a cantilever (3), which is a differential cantilever. The cantilever (3) consists of a horizontal section and an arc section along the water flow direction, with the horizontal section and the arc section being tangent. The upper wall, left wall (1), and right wall (2) are each provided with at least one level of A-shaped grooves (4) protruding towards the upstream direction, the left bank direction, and the right bank direction, respectively. The number of A-shaped grooves (4) on the upper wall, left wall (1), and right wall (2) is equal and corresponds one-to-one. The center line of the A-shaped grooves (4) is horizontal, and the two ends of the A-shaped grooves (4) extend to the ends of the side walls, respectively. The three surfaces of the A-shaped grooves (4) from top to bottom are the upper surface, the bottom surface, and the lower surface. The dihedral angle formed by the upper surface and the bottom surface is an obtuse angle. The intersection of the upper surface and the bottom surface... The line is horizontal, the bottom surface is vertical, and the lower side is horizontal. On the vertical section of the center line of the vertical A-type groove (4), the projection of the upper side on the horizontal plane is shorter than the projection of the lower side on the horizontal plane. The upper side of the highest A-type groove (4) is connected to the end of the cantilever (3) through a vertical transition surface. The lower side of the lowest A-type groove (4) is the bottom plate (5) of the stilling basin or the bottom surface of the C-type groove (8). When the A-type groove (4) has two or more levels, the adjacent two levels of A-type groove (4) are connected through a vertical transition surface. The top of the lower wall is provided with an upward-sloping outlet slope (6) along the direction of water flow. The lower wall is also provided with at least one B-type groove (7) protruding downstream. The center line of the B-type groove (7) is horizontal. The two ends of the B-type groove (7) extend to the end of the side wall. The three sides of the B-type groove (7) from top to bottom are the upper side, the bottom side and the lower side. The dihedral angle formed by the upper side and the bottom side is obtuse. The intersection line of the upper side and the bottom side is horizontal. The bottom side is vertical. The dihedral angle formed by the bottom side and the lower side is obtuse. The intersection line of the bottom side and the lower side is horizontal. The upper side of the highest B-type groove (7) is connected to the outlet slope (6) through a vertical transition surface. The dihedral angle formed by the lower side of the lowest B-type groove (7) and the bottom plate (5) of the stilling basin is obtuse. When the B-type groove (7) has two or more levels, the adjacent B-type grooves (7) are connected by a vertical transition surface. The bottom plate (5) of the stilling basin is provided with at least one level of C-shaped groove (8). The center line of the C-shaped groove (8) is horizontal and points to the left bank and the right bank respectively. The two ends of the C-shaped groove (8) extend to the left wall (1) and the right wall (2) respectively. Both sides of the C-shaped groove (8) are vertical. The bottom surface of the C-shaped groove (8) is horizontal. When the C-shaped groove (8) has two or more levels, each level of the C-shaped groove (8) is stepped. The depth of each level of the C-shaped groove (8) relative to the bottom plate (5) of the stilling basin gradually increases from upstream to downstream.

2. The concave irregular-shaped energy dissipation pool as described in claim 1, characterized in that: The angle α of the sloping section (3) is 30° to 45°, and the radius of the arc segment is... R ≥ The length of the horizontal section of the sill (3) along the direction of water flow L1 = (0.3~0.4) R , ,in: The velocity of the water flowing into the sill (3); D 1 The critical water depth for the water flow entering the sill (3) is used to characterize the characteristic depth of the water flow across the cross section. , denoted as ...

3. The concave irregular-shaped energy dissipation pool as described in claim 1, characterized in that: At least two levels of A-type grooves (4) are provided on the upper wall, left wall (1) and right wall (2). The height of each transition surface on the upper wall, left wall (1) and right wall (2) is equal. The dihedral angle formed by the upper side and bottom surface of each level of A-type groove (4) is equal. The height of the bottom surface of each level of A-type groove (4) is equal.

4. The concave irregular-shaped energy dissipation pool as described in claim 3, characterized in that: The height h1 of the transition surface between the upper wall, left wall (1) and right wall (2) is 1 / 4 to 1 / 3 of the height h2 of the bottom surface of the A-type groove (4). The dihedral angle β formed by the upper side surface and the bottom surface of the A-type groove (4) is 115° to 130°. The distance of the lower side surface of the highest A-type groove (4) on the vertical section perpendicular to the center line of the A-type groove (4) is... d1 4 / 3Rsinα, where R is the radius of the arc segment of the cantilever (3) and α is the cantilever angle of the cantilever (3); the distance on the vertical section of the lower side of the lowest A-type groove (4) located on the upper wall and perpendicular to the center line of the A-type groove (4) is 4 / 3Rsinα, where R is the radius of the arc segment of the cantilever (3) and α is the cantilever angle of the cantilever (3); d2 It is 1 / 3 of the length L of the stilling basin. The length L of the stilling basin is the distance from the bottom plate (5) of the stilling basin along the upstream to the downstream direction.

5. The concave irregular-shaped energy dissipation pool as described in any one of claims 1 to 4, characterized in that: On the vertical section of the center line of the vertical B-type groove (7), the projection of the upper side of the same level B-type groove (7) on the horizontal plane is shorter than the projection of the lower side on the horizontal plane. The line segment corresponding to the upper side of the highest B-type groove (7) is symmetrically arranged with the line segment corresponding to the water outlet slope (6). The axis of symmetry passes through the midpoint of the line segment corresponding to the highest transition surface located on the lower side wall, and the axis of symmetry is horizontal.

6. The concave irregular-shaped energy dissipation pool as described in claim 5, characterized in that: The height h3 of the transition surface located on the lower side wall and at the highest position is equal to the height h4 of the bottom surface of the B-type groove (7). The dihedral angle γ formed by the lower side of the lowest B-type groove (7) and the bottom plate (5) of the stilling basin is 135° to 180°.

7. The concave irregular-shaped energy dissipation pool as described in claim 5, characterized in that: The B-type groove (7) is the first level. The height h5 of the lower side of the B-type groove (7) is 1 / 3 of the depth H of the stilling pool. The depth H of the stilling pool is the height difference between the bottom plate (5) of the stilling pool and the horizontal section of the sill (3).

8. The concave irregular-shaped energy dissipation pool as described in any one of claims 1 to 4, characterized in that: The C-shaped groove (8) has at least two levels, each level of the C-shaped groove (8) is stepped, the step height of each level of the step is equal, and the step width of each level of the step is equal.

9. The concave irregular-shaped energy dissipation pool as described in claim 8, characterized in that: The step height h6 of each step is 1 / 6 to 1 / 4 of the depth H of the stilling pool. The depth H of the stilling pool is the height difference between the bottom plate (5) of the stilling pool and the horizontal section of the sill (3).

10. The concave irregular-shaped energy dissipation pool as described in claim 8, characterized in that: The sum of the tread widths d3 of each step is 1 / 3 of the length L of the stilling basin.

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