Overflow structure, hydraulically equipped dam

Description

[0001] The invention relates to a spillway or discharge device, as well as a hydraulic dam equipped with it.

[0002] One area of ​​the invention relates to flood spillways, weirs, spillways, gates and weir flaps, for example for a hydraulic dam or other.

[0003] One of the major safety challenges related to the operation and monitoring of dams concerns flood risk. The vast majority of dams are equipped with spillways that limit the maximum water level in the reservoir. There are several families and types of spillways. Among them are profiled weirs. On these structures, water is discharged by overflow. There is a standardization of the profile of these weirs, which depends on the design flow rate, corresponding to the optimal operation of the spillway. This flow rate is associated with a water level upstream of the weir, called the design head. When this flow rate is exceeded, the risk of the water column breaking away is significant. Once the water column breaks away, the flow over the weir becomes unstable. These instabilities are damaging to the structure and / or its mechanical components.

[0004] Document US-A-3 464 210 relates to a dam whose upper edge is saddle-shaped with a concave slope and indicates that it is intended to break the regularity of the water's oscillations.

[0005] Document FR-A-725 373 describes a dam having a spillway plate with wedge-shaped elements ending at the top of the dam crest to give the water table and indicates that it is intended to give the water table a wavy shape and prevent vibrations of the water vein.

[0006] The CN-B-111 042 072 document describes a spillway, the upper end of which has inverted isosceles trapezoidal overflow openings.

[0007] The geometries known from these documents present drawbacks.

[0008] These known geometries allow for aeration of the overflowing aquifer to ensure that the air surrounding the free-falling water jet is close to atmospheric pressure. This virtually eliminates the risk of jet pulsation.

[0009] The overflow is the free-falling jet of water formed downstream of a weir, which can resemble a waterfall. Under certain conditions, air currents that form beneath the overflow can cause the water table to fluctuate. These air currents are due to a pressure difference between atmospheric pressure (found above the water table) and the low pressure that forms beneath it. By aerating the water table using the methods mentioned above, the atmospheric pressure beneath it is lowered, and the intensity of the air currents is significantly reduced.

[0010] However, the geometries known from these documents do not provide performance on throughput.

[0011] We are looking in particular to increase the flow rate that passes over the threshold compared to the known documents mentioned above, without there being any detachment.

[0012] The separation is characterized by the presence of a volume of air between the upper surface of the sill and the water.

[0013] An objective of the invention is to obtain a spillway structure, as well as a hydraulic dam equipped with it, where the flow rate admissible by the weir before separation is increased to widen the normal operating range of the weir.

[0014] To this end, a first object of the invention is a spillway according to claim 1.

[0015] Thanks to the invention, the hydraulic performance of the spillway is improved. This new geometry shifts the water flow separation point upwards in the head-discharge relationship, thus increasing the permissible head without separation. The invention makes it possible to increase the maximum permissible discharge over the upper weir surface without observing separation of the overflowing water layer, that is, without air being forced between the overflowing water layer and the upper weir surface.

[0016] In particular, the invention increases the permissible flow rate without detachment compared to the structures described in the documents mentioned above. The invention also improves the flow's adhesion to the surface compared to the structures described in the documents mentioned above.

[0017] In particular, the invention is such that it makes it possible to increase by at least 20%, or even by at least 50% or more than 100%, the permissible flow rate without detachment, compared to a standard threshold of constant profile along the transverse width direction.

[0018] Claims 2 to 25 relate to embodiments of the work.

[0019] A second object of the invention is a hydraulic dam according to claim 26.

[0020] The invention will be better understood upon reading the following description, given solely by way of non-limiting example with reference to the figures below in the attached drawings. The embodiments of figures 7A-C , 10 , 11 , 12 et 13 are not part of the claimed invention, but help to understand the invention. The figure Fig. 1A This represents a schematic, vertical cross-sectional view of a weir in a spillway, according to the state of the art. figure 1B This represents a schematic, vertical cross-sectional view of a weir on a dam, according to the state of the art, in the case of groundwater detachment. figure 2 represents a schematic perspective view of a spillway structure, following a first embodiment of the invention. figure 3 represents a schematic perspective view of a spillway structure following the first embodiment of the invention of the figure 2 showing the water flow velocity in shades of gray. figure 4 represents a schematic vertical cross-sectional view of a basic profile of prescribed shape from which a weir is constructed according to the first embodiment of the invention. figures 2 And 3 . There figure 5A represents a schematic perspective view from a first viewpoint of a spillway structure according to another first embodiment of the invention. figure 5B represents a schematic perspective view from a second viewpoint of a spillway structure according to the first embodiment of the invention. figure 5C represents a schematic perspective view from a third viewpoint of a spillway structure according to the first embodiment of the invention. figure 6A represents a schematic perspective view from a first viewpoint of a spillway structure according to a (second) embodiment of the invention. figure 6B represents a schematic perspective view from a second angle of a spillway structure according to the second embodiment of the invention. figure 6C represents a schematic perspective view from a third viewpoint of a spillway structure according to the second embodiment of the invention. figure 7A represents a schematic perspective view from a first viewpoint of a spillway structure according to a (other) third embodiment. The figure 7B represents a schematic perspective view from a second viewpoint of a spillway structure according to the third embodiment. figure 7C represents a schematic perspective view from a third viewpoint of a spillway structure according to the third embodiment. figure 8 represents a flow rate on the ordinate as a function of a dimensional ratio of the hydraulic head on the weir on the abscissa, on the one hand for a structure following the first example of the invention of figures 2 , 3 And 4 and on the other hand for a standard threshold of the state of the art. The figure 9 represents a schematic perspective view of a spillway structure, following a second embodiment of the invention. figure 10 represents a schematic front view of a spillway structure according to a fourth embodiment. figure 11 represents a schematic top view of a line passing through the vertices of a spillway structure according to the fourth embodiment. figure 12 represents a schematic cross-sectional view of a spillway structure according to the fourth embodiment. figure 13 This represents a schematic cross-sectional view of a spillway structure, following a variant of the fourth embodiment. figure 14 represents a schematic horizontal cross-sectional view, from above, of a portion of the overflowing structure according to the first example of implementation of the figures 2 And 3 and following the second example of the implementation of the invention of the figure 9 . There figure 15 represents a flow rate on the ordinate as a function of a dimensional ratio of the hydraulic head to the weir on the abscissa for a following the second embodiment of the invention of the figure 9 .

[0021] To figures 2 à 15 The spillway structure 1 comprises an upstream face 2 and an upper surface 4, the weir crest, which is located downstream of the upstream face 2 along the horizontal direction Ox of length running from upstream to downstream. Also shown in these figures are the vertical direction Oz of height, oriented from bottom to top, and the horizontal transverse direction Oy of width, which is perpendicular to the horizontal direction Ox of length running from the upstream face 2 to the upper surface 4, the weir crest, and perpendicular to a vertical direction Oz of height. The upper surface 4, the weir crest, slopes downwards. The spillway structure 1 may include another downstream surface connected downstream to the upper surface 4, the weir crest. Alternatively, the spillway structure 1 may not include another downstream surface connected downstream to the upper surface 4, the weir crest.The upstream face 2 (and the other downstream surface, if present) are lower than the upper sill crest surface 4. The upstream face 2 acts as an obstacle to the flow of water, retaining it up to a certain height defined by the upper sill crest surface 4. When the water on the upstream side of the face 2 rises above the upper sill crest surface 4, it overflows downstream. The upper sill crest surface 4 then accommodates the water flowing from upstream to downstream. The upper sill crest surface 4 extends at least along the horizontal transverse direction Oy.

[0022] The spillway structure 1 according to the invention can be part of, for example, a flood spillway, a spillway weir, a weir, a spillway gate, or a weir flap, which may be part of a hydraulic dam or other structure. For example, the spillway structure 1 according to the invention could more generally be part of a basin where water may be discharged, such as, for example, a discharge basin of a nuclear power plant, or a factory basin, or in a water distribution network, such as, for example, a storm overflow.

[0023] According to the invention, to figures 2 à 6 , 8 , 9 And 14The upper surface 4 of the threshold crest comprises, along the horizontal transverse direction Oy of width, one (or more) bump 41 and one (or more) hollow 42. Thus, the upper surface 4 of the threshold crest may comprise one (or more) bump 41 and one (or more) hollow 42 in one (or more) plane Pyz of width, parallel to the transverse direction Oy of width and to the vertical direction Oz of height, as shown in particular in figures 2 à 15 The upper surface 4, the threshold crest, may also include one (or more) bump 41 and one (or more) hollow 42 in one (or more) horizontal plane Pxy, parallel to the horizontal direction Ox of length and to the transverse direction Oy of width, as shown in particular in figures 2 à 15 .

[0024] Thus, the upper surface 4 of the threshold may have an alternation of bumps 41 and hollows 42 along the transverse direction Oy of width in the plane Pyz of width, and / or in the horizontal plane Pxy.

[0025] The laws governing a spillway structure, according to the state of the art, are described below, with reference to figures 1A And 1B , in an example where the upper surface 4 threshold crest is rectilinear and horizontal along the transverse direction Oy of width.

[0026] In the state of the art, as represented in the figure 1A , for a water height H above the upper surface 4 of the sill crest upstream of it, i.e. on the upstream face 2 side, a detachment can be observed (shown by the reference DEC to the figure 1B ) of the water vein according to the figure 1B When the water flow rate Q above the upper surface 4 of the sill crest exceeds a design flow rate QD, and when this water height H exceeds a prescribed design load value HD (H > HD) or 1.1 times this prescribed design load value HD (H > 1.1HD), this separation DEC of the water column significantly degrades the performance of the upper surface 4 of the sill crest. In the event of separation, depressions appear at the water / upper surface 4 sill crest interface. This separation DEC can lead to water table fluctuations that are detrimental to the stability of the structure.

[0027] To the figure 1B , this DEC detachment of the water vein is the fact that the trajectory of the lower sheet of the water jet spilling downstream of the upper surface 4 threshold crest is at a non-zero vertical distance above the downstream surface 30.

[0028] The general law of flow rate of water flows from the upper surface 4 crest of the sill gives this flow rate Q of water according to an increasing function of the height H of water above the upper surface 4 crest of the sill upstream of it (height - flow rate law), according to the following equation: Q = C d L 2 gH 3 where L is the width of the upper surface 4 threshold crest along the transverse direction Oy width, g is the acceleration due to gravity and C d is a flow coefficient.

[0029] The flow coefficient C d is variable depending on the height H. Thus the higher the flow coefficient C d, the higher the flow rate Q or in other words the higher the performance of the upper surface 4 crest of the sill.

[0030] In general, the flow coefficient Cd can be given by the following equation: C d = 0 , 495 H H D 0 , 12

[0031] Therefore, when the flow rate Q of water above the upper surface 4 crest of the threshold is equal to the design flow rate QD, the flow rate coefficient C d is equal to 0.495.

[0032] The invention makes it possible to increase the prescribed design load value HD, above which separation DEC is observed. This new geometry shifts the separation point DEC of the water vein upwards in the head-flow relationship and thus makes it possible to increase the allowable head without separation (=prescribed design load value HD) by between 5% and 25%, which is equivalent to an increase in the design flow rate QD without separation of at least 50%.

[0033] The upper sill surface 4 according to the invention creates water vortices and local low-pressure areas upstream of the troughs 42 and water confinement zones upstream of the rises 41. This tends to press the upstream water flow against this upper sill surface 4, thereby increasing the prescribed design head value HD. Thus, thanks to the invention, the spillway structure can be better protected from water table fluctuations.

[0034] According to the invention, particularly in the first embodiment of the invention, shown in figures 2 , 3 And 4 and in the second embodiment of the invention, shown in the figure 9 In each vertical longitudinal plane Pxz, the upper threshold surface 4 (and possibly the downstream portion of the upstream facing surface 2, connected to the upper threshold surface 4) is constructed by homothety with respect to a basic profile C = z(x,0), which has a prescribed shape in a given vertical longitudinal plane POxz, with a prescribed variable homothety ratio HD / H D0 = z(x,y) / z(x,0) along the width coordinate y of the upper threshold surface 4 in the transverse direction Oy. This prescribed variable homothety ratio HD / H D0 = z(x,y) / z(x,0) is non-zero and is a prescribed function, depending on the width coordinate y of the upper threshold surface 4 in the transverse direction Oy. The prescribed homothety ratio HD / H D0 = z(x,y) / z(x,0) is therefore different in several longitudinal vertical planes Pxz, spaced apart from each other along the transverse direction Oy of width.The prescribed variable ratio of homothety HD / H D0 = z(x,y) / z(x,0) increases from a trough 42 to a crest 41 along the transverse direction Oy of width. The prescribed variable ratio of homothety HD / H D0 = z(x,y) / z(x,0) decreases from a crest 41 to a trough 42 along the transverse direction Oy of width.

[0035] According to an embodiment of the invention, represented in figures 2 à 6 , 8 , 9 And 14 The prescribed variable ratio HD / H D0 of homothety, or z(x,y) / z(x,0), is a curve with at least a continuous derivative (C1 continuous) on the coordinates. Therefore, the upper threshold surface 4 is without sharp edges.

[0036] According to an embodiment of the invention, represented in figures 2 , 9 And 14The upper sill surface 4 has, on one upstream side 45, a curve Cxy, which is formed by the hump(s) 41 and the trough(s) 42 in the horizontal Pxy plane(s). The curve Cxy is at least continuously derivative in the horizontal Pxy plane(s). The upstream side 45 is located upstream of the crest of the upper sill surface 4 in each Pxz plane. The upstream side 45 is located upstream of the upper end 40 of the basic profile (C, z(x,0)) in the Pxz plane. Therefore, the hump(s) 41 and the trough(s) 42 propagate in the horizontal Pxy plane(s) and are also present in the horizontal Pxy plane(s). This feature allows for increased flow without separation.

[0037] According to an embodiment of the invention, represented in figures 2 , 3 And 9 , the basic profile C or z(x,0) includes a downstream point (x1 at the figure 4 A reference point is determined, whose homothety transformation along the width coordinate y is located on a downstream straight segment 31 of the upper surface 4 of the threshold ridge. Segment 31 is downstream with respect to the rest of the upper surface 4 of the threshold ridge. The downstream straight segment 31 of the upper surface 4 of the threshold ridge is parallel to the transverse direction Oy of width. This allows for a reference point for the center of the homothety, which can be located on a three-dimensional line along the Oy direction but is not located on the downstream straight segment 31.

[0038] The downstream straight segment 31 of the upper surface 4 threshold crest can be formed by the end edge 31 of the upper surface 4 threshold crest (previous case without other downstream surface).

[0039] In another embodiment, the downstream straight segment 31 of the upper surface 4 threshold crest is connected to another downstream surface (previous case with the other downstream surface).

[0040] According to an embodiment of the invention, represented in figures 2 , 3 , 5AAt 6C, 9, and 14, the prescribed variable homothety ratio HD / H D0 = z(x,y) / z(x,0) is periodic along the transverse direction Oy of width. The prescribed variable homothety ratio HD / H D0 = z(x,y) / z(x,0) can be periodic with respect to a prescribed repetition width λ (period or wavelength) along the transverse direction Oy of width. Thus, points 411 of the same height (along the vertical direction Oz of height) of each of the pairs of two consecutive humps 41 along the transverse direction Oy of width have the same constant spacing distance between these two points 411, this constant spacing distance being equal to the prescribed repetition width λ, as shown in the figure 7A Similarly, according to one embodiment of the invention, points 421 of the same height (along the vertical Oz direction of height) of each pair of two consecutive hollows 42 along the transverse Oy direction of width have the same constant spacing distance between these two points 422, this constant spacing distance being equal to the prescribed repetition width λ, as shown in the figure 7C .

[0041] According to the invention, as represented in figures 2 And 3 , 5A, 5B, 5C , 6A, 6B, 6C , 9 And 14 , the prescribed variable ratio of homothety HD / H D0 = z(x,y) / z(x,0) is sinusoidal between the bumps 41, which are close to each other and / or between the hollows 42, which are close to each other as a function of a y coordinate of width of the upper surface 4 of threshold along the transverse direction Oy of width.

[0042] According to an embodiment of the invention, represented in figures 2 And 3 , 9 And 14 , the prescribed variable ratio of homothety HD / H D0 = z(x,y) / z(x,0) is defined by H D = H D 0 1 + A 1 + cos 2 π λ y where A is a prescribed height amplitude, which is positive and non-zero, λ is the prescribed repetition width λ along the transverse direction Oy of width, y is the width coordinate of the top surface 4 of threshold along the transverse direction Oy of width, H D0 is a prescribed minimum value of dimensioning load.

[0043] More generally, according to one embodiment, the bumps 41 and / or the hollows 42 may not be periodic along the transverse direction Oy of width. An example of such a non-periodic embodiment is shown in figures 10, 11 , 12 et 13 , which are views of the same work from different angles, as mentioned above. To these figures 10, 11 , 12 et 13 , points B1, B2, B3, B4 are peaks of bumps 41, points C1, C2, C3 are troughs of hollows 42.

[0044] We can imagine more pronounced deformations along a preferred direction. Thus, the Y spacing distance (represented at the figure 2 The distance Y between adjacent bumps 41 (for example, the spacing distance Y taken at the top of adjacent bumps 41) along the transverse direction Oy can be variable, and can be greater than or equal to 0.6 times a prescribed width value Y0 and less than or equal to 1.4 times the prescribed width value Y0. Similarly, the distance Y between adjacent hollows 42 (for example, the spacing distance Y taken at the lowest point of the hollows 42) along the transverse direction Oy can be variable, and can be greater than or equal to 0.6 times a prescribed width value Y0 and less than or equal to 1.4 times the prescribed width value Y0.

[0045] In each pair of two consecutive bumps 41 along the transverse direction Oy of width, the prescribed variable ratio HD / H D0 of homothety can be defined in the manner indicated above between these adjacent bumps 41 and / or in each pair of two consecutive hollows 42 along the transverse direction Oy of width.

[0046] The invention thus applies a deformation to the upper surface 4 of the threshold, which is propagated in a variable manner depending on the y-coordinate along the transverse direction Oy of width, as shown for example in the figures 2 , 3 , 9 And 14 We thus have an upper surface 4 of threshold with a vertical profile varying along the transverse direction Oy of width.

[0047] More general embodiments of the z(x,y) coordinates of the upper threshold surface 4 according to the invention are described below, in which the embodiments described above of the figures 2 à 6 , 8 , 9 And 14 .

[0048] According to one embodiment of the invention, the upper threshold surface 4 has a coordinate z(x,y) along the vertical Oz direction with height, this coordinate z(x,y) depending on the x coordinate of the upper threshold surface 4 along the horizontal Ox direction with length and depending on the y coordinate of the upper threshold surface 4 along the transverse Oy direction with width, according to the following equation: z x y = z x 0 1 + A y . 1 + f y .

[0049] The basic profile C = z(x,0) has a prescribed convex shape in the prescribed longitudinal vertical plane POxz, parallel to the horizontal direction Ox of length and to the vertical direction Oz of height.

[0050] A(y) is a first height function, which is continuous, greater than zero and less than or equal to 0.5.

[0051] f(y) is a second function, which is continuous, which varies along the y coordinate and which is greater than or equal to -1 and less than or equal to 1.

[0052] According to one embodiment of the invention, x 1 is defined (represented for the first example of the figure 4 , the basic profile for the second example of the figure 9 (not being represented) as the minimum or maximum x-coordinate in absolute value for the basic profile z(x,0). We define x2 as the x-coordinate of the profile z(x,0), which is different from x1 and which is defined such that z(x2,0) = z(x1,0). We define the distance d = |x2 - x1|. We define the distance D1 between the peaks 411 of the humps 41, which are close to each other, and the distance D2 between the low points 421 of the troughs 42, which are close to each other, such that D1 ≤ 10d and / or D2 ≤ 10d.

[0053] According to one embodiment of the invention, 0 < A(y) ≤ 0.5.

[0054] According to one embodiment of the invention, the first function A(y) is equal to a prescribed, positive, and non-zero constant A. The second function f(y) is defined between adjacent bumps 41 and / or between adjacent hollows 42 by f(y) = cos (2πy / λk), where λk is a spacing distance Y prescribed along the transverse direction Oy and associated with each pair k of adjacent bumps 41 and / or hollows 42. This embodiment therefore corresponds to the first example, shown in Figures 1 and 2. figures 2 And 3 and the second example of the figure 9 .

[0055] According to one embodiment of the invention, the spacing distance λ k is different between several pairs of neighboring bumps 41 and / or neighboring hollows 42.

[0056] According to another embodiment of the invention, the spacing distance λ k is identical between several pairs of neighboring bumps 41 and / or neighboring hollows 42.

[0057] Embodiments of the second function f(y), the first function A(y) and the basic profile C = z(x,0) of prescribed shape are described above.

[0058] Following the first example of implementation of the invention at the figure 4 , the basic profile C = z(x,0) of prescribed shape comprises in the basic POxz plane, several segments, which have different geometric shapes and which are connected to each other, with for example a continuity of the tangent between the segments and in the segments.

[0059] A downstream segment C0 of the prescribed basic profile C extends from the upper end 40 of this profile C along a decreasing curve downstream of this upper end 40 in the horizontal Ox direction of length and downwards, i.e., in a downstream quadrant 43. For example, the origin O of the coordinate system of the x-coordinate of length along the horizontal Ox direction of length, of the y-coordinate of width along the transverse Oy direction of width, and of the z-coordinate of height along the vertical Oz direction of height, is located at the upper end 40 of the prescribed basic profile C. The decreasing curve of the downstream segment C0 of the prescribed basic profile C downstream can be z = -0.5x < 1.85.

[0060] The downstream section C0 of the prescribed basic profile C can be connected upstream of the upper end 40 of the prescribed basic profile C to one or more upstream sections C1, C2, C3, connected one after the other, i.e., in an upstream quadrant 44. The downstream section C0 and the upstream section C1 have a continuous tangent to each other at the upper end 40. Each upstream section C1, C2, C3 can, for example, be in the shape of a circular arc. The radii of the circular arcs of the upstream sections C1, C2, C3 can be decreasing, with centers located progressively higher and further upstream, moving from one section C1, C2, C3 to the next from downstream to upstream. The arcs of circles have a continuity of their tangent one after the other from downstream to upstream.

[0061] Thus, for example, the first upstream section C1 can be a first circular arc C1, centered on a first center A1 and having a first radius R1, connected to the upper end 40 of the prescribed basic profile C. The second upstream section C2 can be a second circular arc C1, centered on a second center A2 and having a second radius R2, connected to the first upstream section C1 and located upstream of the first upstream section C1. The third upstream section C3 can be a third circular arc C3, centered on a third center A3 and having a third radius R3, connected to the second upstream section C2 and located upstream of the second upstream section C2.

[0062] Below, an example of the basic profile C = z(x,0) of prescribed shape is given, with the coordinates and radii expressed proportionally to the prescribed value HD of the design load.

[0063] The first center A 1 has, for example, coordinates x= 0 and z = -0.5. The first radius R 1 is, for example, equal to 0.5. The first arc of the circle C 1 extends within the range of validity of the abscissa x from -0.175 to 0.

[0064] The second center A2, for example, has coordinates x = -0.105 and z = -0.219. The second radius R2 is, for example, equal to 0.2. The second arc of the circle C2 extends within the range of validity of the abscissa x from -0.276 to -0.175.

[0065] The third center A3, for example, has coordinates x = -0.2418 and z = -0.136. The third radius R3, for example, is equal to 0.04. The third arc of the circle C3 extends within the range of validity of the abscissa x from -0.2818 to -0.276.

[0066] Of course, the basic profile C of prescribed shape may be different from the example mentioned above, the homothety mentioned above being able to apply to any basic profile C = z(x,0) of prescribed shape.

[0067] There figure 8 represents the flow rate Q (expressed in m³ / s), calculated by computer simulation, on the ordinate, as a function of the ratio H / H D0 on the abscissa, on the one hand for a surface area greater than 4 of standard threshold known according to the figure 1A (flow rate Q represented by points formed by small circles filled with white, surface 4 called standard weir) and on the other hand for the upper surface 4 of the weir of the spillway structure following the first example of figures 2 , 3 And 4 according to the invention (flow rate Q, Q INV represented by points formed of small circles filled with black, surface 4 called threshold with homothetic profile).

[0068] To the figure 8 , the upper surface 4 of standard threshold known according to the figure 1A corresponds to the basic C profile of prescribed shape of the figure 4 , extended in a straight line and horizontally along the Oy direction with width, that is to say with the amplitude A taken zero in the above-mentioned formula of the homothety ratio HD / H D0 . = z(x, y) / z(x,0).

[0069] To the figure 8 , the upper surface 4 of the sill of the spillway according to the invention corresponds to the homothetic embodiment described above for two identical distances λ of separation, for an amplitude A = 5% of H D0 and a distance λ of separation = of 75% of H D0 and for a spillway width (y) fixed at 1.5 m, in the formula of the prescribed variable ratio of homothety HD / H D0 = z(x, y) / z(x,0).

[0070] To the figure 8 , no detachment of the water layer is observed on the upper surface 4 of the weir of the spillway according to the invention for abscissas H / H D0 up to 1.7, whereas such a detachment DEC of the water layer on the upper surface 4 of the standard weir is observed for an abscissa H / H D0 greater than 1.34.

[0071] Therefore, for the standard weir, the flow rate without separation is only valid for H / H D0 less than or equal to 1.34. For the standard weir, for H / H D0 equal to 1.34, the flow rate (Q st) is equal to 5 m³ / s. The maximum flow rate of the standard weir without separation is therefore 5 m³ / s.

[0072] There figure 8 shows that for points having the abscissa of the ratio H / H D0 equal to 1.67 the flow rate Q INV of the upper surface 4 of the weir of the spillway according to the invention without separation is equal to 7.8 m 3< / s, and is therefore increased by 56% compared to the maximum flow rate of the standard weir without separation of 5 m 3< / s.

[0073] Following the second example of an embodiment of the invention in the figure 9 , the basic profile C = z(x,0) of prescribed convex shape in the prescribed longitudinal vertical plane POxz includes a Bézier curve with 4 control points of prescribed coordinates in the prescribed longitudinal vertical plane POxz.

[0074] This Bézier curve with 4 control points can be: B t = 1 − t 3 ⋅ P 0 + 3 ⋅ 1 − t 2 ⋅ t ⋅ P 1 + 3 ⋅ 1 − t ⋅ t 2 ⋅ P 2 + t 3 ⋅ P 3 where P0, P1, P2, P3 are the four control points with prescribed coordinates in the prescribed longitudinal vertical plane POxz, the Bézier curve being defined in a coordinate system originating at the upper end 40 of the basic profile z(x,0). The prescribed longitudinal vertical plane POxz is parallel to the horizontal Ox direction of length and to the vertical Oz direction of height. The parameter t varies from 0 to 1. The pair B(t) denotes the x and z(x,0) coordinates of the basic profile in the prescribed longitudinal vertical plane POxz. The four control points P0, P1, P2, P3 with prescribed coordinates are given by their prescribed x and z coordinates in the prescribed longitudinal vertical plane POxz. Therefore, the x coordinate of the basic profile in the prescribed longitudinal vertical plane POxz is the combination B(t) mentioned above as a function of the x coordinates of the 4 control points P 0 , P 1 , P 2 , P 3 .The z coordinate of the basic profile in the prescribed longitudinal vertical plane POxz is the combination B(t) mentioned above as a function of the z coordinates of the 4 control points P 0 , P 1 , P 2 , P 3 .

[0075] According to one embodiment, P 0 has the following coordinates: x H D 0 = − 0.2818 ± 20 % And 1 H D 0 = − 0.150 ± 20 % P1 has the following coordinates: − 0.2818 − 0.2 ⋅ 0.2818 ≤ x H D 0 ≤ − 0.2818 + 0.2 ⋅ 0.2818 And − 0.12 ≤ z H D 0 ≤ 0.2 , P 2 has the coordinates − 0.2 ≤ x H D 0 ≤ 0.5 And − 0.05 ≤ z H D 0 ≤ 0.3 P3 has the following coordinates: 0.7 − 0.2 ⋅ 0.7 ≤ x H D 0 ≤ 0.7 + 0.2 ⋅ 0.7 And − 0.0904 − 0.2 ⋅ 0.0904 ≤ z H D 0 ≤ − 0.0904 + 0.2 ⋅ 0.0904 , the coordinates being expressed in meters, where H D0 is the minimum prescribed value of design load, . 0.097 − 0.2 ⋅ 0.097 ≤ A ≤ 0.097 + 0.2 ⋅ 0.097 , 1.34 − 0.2 ⋅ 1.34 ≤ λ k ≤ 1.34 + 0.2 ⋅ 1.34 .

[0076] According to one embodiment, 0.01 ≤ A ≤ 0.2 and 0.5 ≤ λ k ≤ 1.5 .

[0077] Following the second example of implementation, P 0 has the following coordinates: x H D 0 = − 0.2818 et z H D 0 = − 0.150 , P 1 has the following coordinates: x H D 0 = − 0.2818 et z H D 0 = − 0.200 , P 2 has the following coordinates: x H D 0 = 0.2930 et z H D 0 = 0.3000 , P 3 has the following coordinates: x H D 0 = 0.7000 et z H D 0 = − 0.0904 , A = 0.097 , λ k = 1.34 .

[0078] The Bézier curve can be connected to the upstream face 2 at a connection point Pr in the prescribed longitudinal vertical plane POxz. The point Pr corresponds to the minimum deformation depth of the upstream face 2.

[0079] The point P r where the Bézier curve connects can have coordinates -0.2818 - 0.2 ⋅ 0.2818 ≤ x H D 0 ≤ − 0.2818 + 0.2 ⋅ 0.2818 And z H D 0 ≤ − 1 For example, the point Pr where the Bézier curve connects can have the following coordinates x H D 0 = − 0.2818 And − 4.5 ≤ z H D 0 ≤ − 1 .

[0080] There figure 15 represents the flow rate Q (expressed in m³ / s), calculated by computer simulation, on the ordinate, as a function of the ratio H / H D0 on the abscissa, on the one hand for a surface area greater than 4 of standard threshold known according to the figure 1A (flow rate Q represented by the squares filled with white, surface 4 called standard threshold) and on the other hand for the upper surface 4 of the threshold of the spillway structure according to the second example of the figure 9 according to the invention (flow rate Q, Q INV represented by points formed of small circles filled with black, surface 4 called threshold with homothetic profile).

[0081] To the figure 15 , the upper surface 4 of the sill of the spillway according to the invention corresponds to the homothetic embodiment described above for two identical distances λ of separation, for an amplitude A = 5% of H D0 and a distance λ of separation = of 75% of H D0 and for a spillway width (y) fixed at 1.5 m, in the formula of the prescribed variable ratio of homothety HD / H D0 . = z(x, y) / z(x,0).

[0082] To the figure 15 , no detachment of the water layer is observed on the upper surface 4 of the weir of the spillway according to the invention for abscissas H / H D0 up to 2.3, whereas such a detachment DEC of the water layer on the upper surface 4 of the standard weir is observed for an abscissa H / H D0 greater than 1.34.

[0083] Therefore, for the standard weir, the flow rate without separation is only valid for H / H D0 less than or equal to 1.34. For the standard weir, for H / H D0 equal to 1.34, the flow rate (Q st) is equal to 17 m³ / s. The maximum flow rate of the standard weir without separation is therefore 17 m³ / s.

[0084] There figure 15 shows that for points having the abscissa of the ratio H / H D0 equal to 2.3, the flow rate Q INV of the upper surface 4 of the weir of the spillway according to the invention without separation is equal to 46 m 3< / s, and is therefore increased by 170% compared to the maximum flow rate of the standard weir without separation of 17 m 3< / s.

[0085] According to one embodiment of the invention, the amplitude of a deformation (vertical distance between the top of a bump 41 and a low point of a hollow 42) along the Oz height direction is less than 50% of the threshold thickness, which is taken along the Ox length direction between a vertical edge 21 of the upstream facing 2 and a vertical edge 31 of the surface 4.

[0086] According to one embodiment of the invention, the horizontal distance between the peaks of two adjacent bumps 41 (or local maxima) is less than 2 times the threshold thickness, which is taken along the Ox direction of length between a vertical edge 21 of the upstream facing 2 and a vertical edge 31 of the surface 4.

[0087] In the embodiments of the invention, represented in figures 2 à 6 , 8 , 9 And 14 , the upstream facing 2 has in top view one (or more) concavity 22 extending downwards the hollow(s) 42 to the lower vertical edge 21 of the end of the upstream facing 2.

[0088] In the modes of embodiment of figures 2 à 15 The upstream face 2 comprises or is formed by a surface parallel to the Oz direction of height, which connects to the upper surface 4 of the threshold. Thus, the upstream face 2 comprises or is formed by a surface composed of generatrices parallel to the Oz direction of height. This surface of the upstream face 2 may be curved in top view, as shown in the diagram. figures 2 , 3 , 5A, 5B, 5C .

[0089] In the modes of embodiment of figures 2 , 3 , 4 , 5A, 5B, 5C , the upstream facing 2 has a surface 23, which is overhanging relative to the lower vertical edge 21 of the end of the upstream facing 2. This surface 23 extends downwards the bump(s) 41.

[0090] The invention makes it possible to generate three-dimensional modifications of the upper surface 4 threshold crest for a fixed spill length along the transverse direction Oy of width.

[0091] Thus, the invention could also be applied to the upper surface 4 threshold crest described above, making changes of direction or zigzags in top view, to have an increased total length along these changes of direction in the horizontal plane Pxy.

Claims

1. Spillway structure (1) comprising an upstream facing (2) which obstructs the flow of water, and an upper threshold surface (4) forming a crest, the upper threshold surface (4) forming a crest being higher than the upstream facing (2) and located downstream of the upstream facing (2), the upper threshold surface (4) forming a crest sloping downwards towards the downstream, the upper threshold surface (4) forming a crest extending along at least one transverse direction (Oy) of width, which is perpendicular to at least one horizontal direction (Ox) of length extending from the upstream facing (2) towards the downstream and which is perpendicular to a vertical direction (Oz) of height, the upper threshold surface (4) having at least one bump (41) and at least one hollow (42) in at least one plane (Pyz) of width, parallel to the transverse direction (Oy) of width and to the vertical direction (Oz) of height and / or in at least one horizontal plane (Pxy), parallel to the horizontal direction (Ox) of length and to the transverse direction (Oy) of width, characterised in that in each vertical longitudinal plane (Pxz), parallel to the horizontal direction (Ox) of length and to the vertical direction (Oz) of height, the upper threshold surface (4) corresponds to a homothety, having a prescribed variable homothety ratio (HD / HD0 , z(x,y) / z(x,0)), which is non-zero and depends on the width coordinate (y) of the upper threshold surface (4) in the transverse direction (Oy) of width, relative to a base profile (C, z(x,0)) of prescribed shape in one (POxz) of the longitudinal vertical planes (Pxz), the prescribed variable homothety ratio (HD / HD0 , z(x,y) / z(x,0)) of homothety being increasing from a hollow (42) to a bump (41) along the transverse direction (Oy) of width, the prescribed variable homothety ratio (HD / HD0 , z(x,y) / z(x,0)) being sinusoidal between the bumps (41), which are adjacent to each other, and / or between the hollows (42), which are adjacent to each other, as a function of a width coordinate (y) of the upper threshold surface (4) along the transverse width direction (Oy).

2. Structure according to claim 1, characterised in that the prescribed variable homothety ratio (HD / HD0, z(x,y) / z(x,0)) of homothety is a curve that is at least continuously differentiable along at least the width coordinate (y).

3. A structure according to any one of the preceding claims, characterised in that the upper threshold surface (4) has, in the at least one horizontal plane (Pxy) at an upstream side (45) of the upper threshold surface (4), a curve (Cxy), which includes the at least one bump (41) and the at least one hollow (42) and which is at least continuously differentiable.

4. Structure according to any one of the preceding claims, characterised in that the base profile (C, z(x,0)) includes a specific downstream reference point (x1), whose transformation by the homothety along the width coordinate (y) is located on a straight downstream segment (31) of the upper threshold surface (4) forming a crest, the straight downstream segment (31) of the upper threshold surface (4) forming a crest being parallel to the transverse direction (Oy) of width.

5. Structure according to claim 4, characterised in that the straight downstream segment (31) of the upper threshold surface (4) forming a crest is formed by an end edge (31) of the upper threshold surface (4) forming a crest.

6. Structure according to claim 4, characterised in that the straight downstream segment (31) of the upper threshold surface (4) forming a crest is connected to another downstream surface.

7. A structure according to any one of the preceding claims, characterised in that the upper threshold surface (4) has alternating bumps (41) and hollows (42) along the transverse direction (Oy) of width in the width plane (Pyz) and / or in the horizontal plane (Pxy).

8. Structure according to claim 7, characterised in that the bumps (41), which are adjacent to each other, have vertices that are spaced apart along the transverse direction (Oy) of width, by a spacing distance (Y) which is greater than or equal to 0.6 times a prescribed value (Y0) of width and which is less than or equal to 1.4 times the prescribed value (Y0) of width.

9. A structure according to claim 7 or 8, characterised in that the hollows (42), which are adjacent to one another, have bottom points, which are spaced apart along the transverse direction (Oy) of width by a spacing distance (Y) which is greater than or equal to 0.6 times a prescribed width value (Y0) and which is less than or equal to 1.4 times the prescribed width value (Y0).

10. A structure according to any one of claims 1 to 9, characterised in that the upper threshold surface (4) has a coordinate z(x,y) along the vertical height direction (Oz), the coordinate z(x,y) depending on the coordinate x of the upper threshold surface (4) in the horizontal direction (Ox) of length and depending on the coordinate y of the upper threshold surface (4) in the transverse direction (Oy) of width, according to the following equations : z x y = z x 0 1 + A y . 1 + f y where z(x,0) is the base profile (C ) of a prescribed convex shape in a prescribed longitudinal vertical plane (POxz), parallel to the horizontal direction (Ox) of length and to the vertical direction (Oz) of height, A(y) is a first height function, which is continuous, greater than zero and less than or equal to 0.5, f(y) is a second function, which is continuous, varies according to the y-coordinate and is greater than or equal to -1 and less than or equal to 1.

11. Structure according to claim 10, characterised in that D 1 ≤ 10 . d and / or D 2 ≤ 10 . d , where D1 is the distance between the vertices (411) of the bumps (41) that are adjacent to each other, D2 is the distance between the bottom points (421) of the hollows (42) that are adjacent to each other, d = x 2 − x 1 , x1 is the minimum or maximum x-coordinate in absolute value for the profile z(x,0), x2 is the x-coordinate of the profile z(x,0), which is different from x1 and which is defined such that z(x2 ,0) = z(x1 ,0).

12. Structure according to claim 10 or 11, characterised in that 0 < A y ≤ 0.5 .

13. A structure according to any one of claims 10 to 12, characterised in that the first function A(y) is chosen from at least one of the following functions: a continuous function of class C1, a continuous function of class C2, a continuous function of class Cn, where n is an integer greater than or equal to 3, a continuous function of class C∞, an elliptic function over at least one interval between two bumps, a Bézier curve with at most 20 control points over at least one interval between two bumps, at least one semicircle over at least one interval between two bumps, at least one arc of a circle over at least one interval between two bumps, a polynomial of degree less than or equal to 20 on at least one interval between two bumps, a piecewise function defined by polynomials of degree less than or equal to 10 on at least one interval between two bumps, a function with at most 15 pieces defined by polynomials of degree less than or equal to 10 on at least one interval between two bumps.

14. A device according to any one of claims 10 to 13, characterised in that the second function f(y), which is continuous, which varies according to the y-coordinate and which is greater than or equal to -1 and less than or equal to 1, is chosen from at least one of the following functions: a sum of at most 10 sinusoidal functions, a sum of at most 10 sinusoidal functions that are phase-shifted relative to each other.

15. A device according to any one of claims 10 to 14, characterised in that the first function A(y) is equal to a prescribed constant A, which is positive and not zero, the second function f(y) is defined between the bumps (41), which are adjacent to each other, and / or between the hollows (42), which are adjacent to each other, by f y = cos 2 πy / λ k , where λk is a spacing distance (Y) which is prescribed along the transverse direction (Oy) of width and which is associated with each pair (k) of neighbouring bumps (41) and / or neighbouring hollows (42).

16. Structure according to claim 15, characterised in that the spacing distance λk is different between several pairs of neighbouring bumps (41) and / or neighbouring hollows (42).

17. Structure according to claim 15, characterised in that the spacing distance λk is identical between several pairs of neighbouring bumps (41) and / or neighbouring hollows (42).

18. Structure according to any one of the preceding claims, characterised in that the base profile z(x,0) of a prescribed convex shape in a prescribed longitudinal vertical plane (POxz), parallel to the horizontal direction (Ox) of length and to the vertical direction (Oz) of height, is chosen from at least one of the following functions: a continuous convex function, a continuous C1 class function, a continuous C2 class function, a continuous Cn class function, where n is an integer greater than or equal to 3, a continuous function of class C∞, an elliptical function over at least one interval between two bumps, a Bézier curve with at most 20 control points, at least one semicircle, at least one arc of a circle, a polynomial of degree less than or equal to 10, a piecewise function defined by polynomials of degree less than or equal to 10, a function with at most 15 pieces defined by polynomials of degree less than or equal to 10.

19. Structure according to claim 18, characterised in that the basic profile (C, z(x,0)) of a prescribed convex shape in the prescribed longitudinal vertical plane (POxz), parallel to the horizontal direction (Ox) of length and to the vertical direction (Oz) of height, comprises a downstream section (C0)in the form of a prescribed decreasing curve extending from an upper end (40) of the base profile (C, z(x,0)) towards the downstream, and at least one upstream section (C1 , C2 , C3 ), which extends from the upper end (40) of the base profile (C, z(x,0)) upstream and which is formed by at least one arc (C1 , C2 , C3 ) of a circle, the downstream section (C0)and the upstream section (C0)having continuity of their tangents one after the other at the upper end (40).

20. Structure according to claim 19, characterised in that the downstream section (C0) in the form of a prescribed decreasing curve has the coordinate z(x,0) =-0.5.x1.85 in a coordinate system with its origin at the upper end (40) of the profile (C, z(x,0)) for x ≥ 0 in the upstream to downstream direction.

21. Structure according to claim 18, characterised in that the base profile (C, z(x,0)) of a prescribed convex shape in the prescribed longitudinal vertical plane (POxz), parallel to the horizontal direction (Ox) of length and to the vertical direction (Oz) of height, comprises a Bézier curve with 4 control points of prescribed coordinates in the prescribed longitudinal vertical plane (POxz).

22. The structure according to claim 21, characterised in that the Bézier curve with 4 control points is: B t = 1 − t 3 ⋅ P 0 + 3 ⋅ 1 − t 2 ⋅ t ⋅ P 1 + 3 ⋅ 1 − t ⋅ t 2 ⋅ P 2 + t 3 ⋅ P 3 where P0, P1, P2, P3 are the 4 control points with prescribed coordinates in the prescribed longitudinal vertical plane (POxz), the Bézier curve being defined in a coordinate system with its origin at an upper end (40) of the base profile (z(x,0)), t is a parameter varying from 0 to 1.

23. The device according to claim 22, taken in combination with claim 15, characterised in that P0 has the coordinates: x H D 0 = − 0.2818 ± 20 % and z H D 0 = − 0.150 ± 20 %, P1 has coordinates: − 0.2818 − 0.2 ⋅ 0.2818 ≤ x H D 0 ≤ − 0.2818 + 0.2 ⋅ 0.2818 and − 0.12 ≤ z H D 0 ≤ 0.2 , P2 has coordinates − 0.2 ≤ x H D 0 ≤ 0.5 and − 0.05 ≤ z H D 0 ≤ 0.3, P3 has coordinates: 0.7 − 0.2 ⋅ 0.7 ≤ x H D 0 ≤ 0.7 + 0.2 ⋅ 0.7 and − 0.0904 − 0.2 ⋅ 0.0904 ≤ z H D 0 ≤ − 0.0904 + 0.2 ⋅ 0.0904 , the coordinates being expressed in metres, where HD0 is a prescribed minimum dimensioning load value, 0.097 − 0.2 ⋅ 0.097 ≤ A ≤ 0.097 + 0.2 ⋅ 0.097 , 1.34 − 0.2 ⋅ 1.34 ≤ λ k ≤ 1.34 + 0.2 ⋅ 1.34 .

24. Structure according to any one of the preceding claims, characterised in that the vertical distance between the vertice of the bump (41) and the bottom point of the hollow (42) in the height direction (Oz) is less than 50% of a threshold thickness, which is a horizontal distance, taken in the direction (Ox) of length, between a vertical edge (21) at the end of the upstream facing (2) and a vertical edge (31) at the end of the upper threshold surface (4).

25. Structure according to any one of the preceding claims, when they depend at least on claim 7, characterised in that the horizontal distance between the vertices of two adjacent bumps (41) is less than twice a threshold thickness, which is a horizontal distance, taken in the direction (Ox) of length, between a vertical edge (21) at the end of the upstream facing (2) and a vertical edge (31) at the end of the upper threshold surface (4).

26. Hydraulic dam comprising at least one spillway structure (1) according to any one of the preceding claims.