EP1883735A1

EP1883735A1 - Water movement damping device

Info

Publication number: EP1883735A1
Application number: EP06764641A
Authority: EP
Inventors: Pierre Aristaghes; Raphaëlle POUEZEVARA
Original assignee: Saipem SA
Current assignee: Saipem SA
Priority date: 2005-05-20
Filing date: 2006-05-18
Publication date: 2008-02-06
Anticipated expiration: 2026-05-18
Also published as: US7686539B2; ATE497558T1; EP1883735B1; DE602006019956D1; FR2885919B1; ES2360418T3; US20090238645A1; FR2885919A1; WO2006123053A1

Abstract

The present invention relates to a water movement device comprising a flexible wall (1) placed in water close to the surface, substantially vertically in a static rest state, made up of optionally perforated (5) massive unit blocks (4) assembled to one another in strings by cables (2, 3) on which said blocks (1) are threaded or on which said blocks are crimped, said cables comprising: a series of cables (2) disposed vertically (ZZ′) side by side, parallel to one another, and a second series of cables (3) disposed horizontally (XX′) one above another and in parallel, and said vertical cables (2) being suspended or tensioned at their top ends and/or respectively tensioned or moored at their bottom ends, and said blocks including empty orifices (5) passing through them between the front and rear faces (1-1, 1-2) of said wall (1), and/or empty spaces (7) between said blocks, such that said orifices (5) and/or empty spaces between said blocks (7), if any, confer overall porosity on said wall lying in the range 5% to 75%, preferably 20% to 45%, of the area of the vertical section of said wall.

Description

Damping device for water movement

The present invention relates to a device constituting a wall, wall or curtain damping movement (s) of water intended more particularly to damp the jets induced by the propellers of ships as well as choppers and small swells. It is more particularly intended to be installed vertically within pontoons on piles, more precisely below said pontoons between support piles in port facilities.

A port is a space in which the vessels maneuver, using their thrusters (propellers and / or bow thrusters in particular), especially to dock and to leave the berth to which they are moored. These thrusters create jets that can be propagated over long distances and that are likely to cause scouring, that are limited or even eliminated by anti-scouring devices generally at the foot of structures, or in sensitive areas . These jet thrusters can also cause discomfort or mooring difficulties for some nearby boats.

The movement of ships also generates short-term waves, which also cause discomfort for boats, especially those of pleasure or fishing, as well as choppers generated by local winds.

In harbor environments, we generally seek to create protected areas in which the surface of the water remains calm, and many techniques have been developed to date to create these sheltered areas, among which we will mention among others massive dikes, partial dykes, rigid Jarlan type perforated walls, water walls. In all these techniques, one seeks either to reflect the wave by simply returning it offshore, or to dissipate the intrinsic energy of the moving mass of water, or by transforming it directly into heat within the mass of water. water (massive or partial dikes), either by recovering the energy to transform it into electricity (marnantes chambers), or by creating phase shifts within the wave in the case of water walls.

All these systems are highly effective in absorbing heavy swells and especially short swells. But these are usually works massive, because they have to withstand very significant efforts over periods of 30 to 50 years or more.

The solution that consists of "waterproofing" the wharf type piles is not always desirable (apart from its additional cost), because it causes parasitic reflections, whose effect, especially at the bottom of dock or along docks rectilinear, is to increase the agitation, so reduce the comfort or operability of the berths.

With the exception of massive dykes that create a total screen, partial dykes and water walls are very inefficient at absorbing the long wavelengths and choppers generated by currents swirling around the piers or created by the propellers ships approaching their mooring point on a pontoon.

WO 02/26019 discloses a device for dissipating wave energy comprising an array of floating plastic modules assembled by a system of flexible rubber hinges, both in the vertical direction and in the horizontal direction, forming a relatively complex and expensive system to achieve, and relatively fragile-

The complexity of the device described in WO 02/26019 is due to the particular shape of the modules defining particular openings and the shape of the external connecting elements to said modules.

In addition, the flexibility of the articulated system of WO 02/26019 constituted by rubber elastic connection elements external to the various floating modules gives the entire device excessive mobility resulting in wear phenomena and a limited life.

Thus the problem is to provide a device capable of reducing the currents generated by the propellers of ships operating near or within an area that we wish to protect to the maximum by maintaining a virtually flat calm, as well as to reduce small swells and choppers.

Another aim is to provide a device that is less expensive and easier to produce and install than the works of previous embodiments. Another object of the present invention is to provide a device having properties of sufficient resistance to large forces and high loads with a mobility able to allow localized deformations of the device in case of strong swell or chop, but with a mobility limited in order to reduce the phenomena of fatigue and wear and increase the life of the device.

To this end, the present invention provides a damping device for the movement of water such as the current induced by the propellers of the ships, as well as swell and chop constituting a flexible wall, disposed in the water near the surface, substantially vertically. in a static state of rest, comprising solid, possibly perforated, unit blocks assembled to each other in strings by means of cables in which said blocks are threaded or on which said blocks are crimped,

said cables comprising:

A first series of cables arranged vertically (ZZO side by side, parallel to each other, and a second series of cables arranged horizontally (XXO) one above the other parallel, and

each block is pierced right through in the vertical direction and in the horizontal direction, to allow the passage of at least one said vertical cable and at least one said horizontal cable, and each said block is assembled to at least one said vertical cable thus forming a plurality of parallel vertical cable strings, and at least a portion of said blocks, preferably each said block being assembled (s) to at least one said horizontal cable, thereby assuring the assembly of different vertical cable strings between them, and

said vertical cables being suspended or tensioned at their upper ends and / or respectively tensioned or moored at their lower ends, and

the blocks are assembled in a string, the upper faces of one against the lower faces of the others along the said vertical cables, and

said blocks are spaced apart from each other along said horizontal cables by buffers, preferably of elastomeric material, and preferably a sleeve is crimped at each end of each horizontal cable so that said buffers are compressed to a value substantially uniform prestressing, and

said blocks comprise:

• empty holes passing right through between the front and rear faces of said wall and / or Spaced spaces between said blocks, such that said orifices and / or empty spaces between said blocks give said wall a global porosity of said front and rear faces preferably representing 5 to 75%, more preferably 20 to 45%, of the surface of the vertical section of said wall.

"Global porosity" here means a percentage of empty area relative to the total surface of the vertical section of said wall. It is understood that said wall is delimited by:

- The upper and lower faces of the blocks at the ends respectively upper and lower of said vertical cables, and - the outer side faces of the blocks at both ends of said horizontal cables.

The device according to the invention forms a wall also called "curtain" having a certain flexibility allowing deformations in case of current, swell or chop and which allows to create significant pressure drops of the body of water passing through it. its porosity and thus dampen the movements of water, while offering significant strength without risk of rupture due to its flexibility. According to its characteristics (surface mass, porosity, mode of attachment), it will also oppose the transmission of waves for a certain period (typically the waves generated by the passage of ships or choppers), which translates by a transmission coefficient substantially less than 1, that is to say that the values of current, chop or swells are attenuated accordingly.

Beyond this period (whose value depends on the mass and flexibility of the curtain, its porosity, its method of attachment, ...), this transmission coefficient will increase, the curtain tending to oscillate at will waves, which has two advantages: capping forces (impact on sizing anchors, including fatigue), and limiting the increase in agitation because of the low reflectivity of the system.

The positioning of the various blocks resting on each other by gravity, threaded on the same vertical cable, upper faces of one against the lower faces of the others, provides a certain self-locking of said respective upper and lower faces of the two adjacent blocks with respect to others on the same vertical cable. Advantageously, said blocks comprise upper and lower faces of complementary shapes. This embodiment makes it possible to increase the self-locking of said respective upper and lower faces of two adjacent blocks on a vertical cable.

The tensioning of said vertical and horizontal cables and the self-locking of the adjacent blocks on a vertical cable have the effect of stabilizing the shape of said wall by giving it a certain stiffness and maintain the wall in a substantially vertical position or avoid excessive deformation during deformations. due to movements of water such as current, swell or chop. Indeed, the blocks resting on each other, create a prestressing of the assembly which maintains said string in a substantially straight vertical line (ZZ), thus opposing the deformations of said string in the plane (YZ).

The prestressing of the horizontal cables further stabilizes the shape of the device by holding each of the horizontal strings in a substantially straight horizontal line, thus opposing the deformations of said strand in the plane (XY), which gives a certain stiffness to the curtain of rosaries , thus keeping it preferentially in the plane (XZ). In total, the stiffness of the device makes it possible to virtually eliminate the movements of small amplitudes that would not be required by the damping of the swell or the chop, thus sparing wear and unnecessary fatigue of said cables.

However, said elastomeric buffers provide sufficient flexibility to the device according to the invention to allow localized deformations in case of significant effort due to swell or chop.

Thus, for low values of the speeds of the water particles generated by the current of the helices, or by the swell or chop, the device according to the invention remains substantially plane and vertical while reducing said particle velocities. It is only when the particle speeds increase significantly, that we observe movements of the device according to the invention. These high speeds, which are due for example to a strong swell, lead to oscillations of the device according to the invention according to the waves. This makes it possible to limit the forces that the supporting structures of the device according to the invention must bear, as well as the piles of the pontoons, thus limiting the requirements in terms of strength and fatigue resistance of the piles and anchorages, and increasing the duration of life of the device according to the invention. Preferably, the vertical cables are suspended and tensioned by the weight of all of said blocks resting on each other by gravity, the lower terminal block being held on the cable so as to retain all of said blocks of the same vertical cable . It is understood that the blocks according to the invention are not floating and are therefore much heavier than water, and more particularly, they can be advantageously made of concrete, plastic material or composite material.

More particularly, at least a portion of said blocks have said orifices, and more particularly, each block comprises at least one said orifice.

Preferably, each block comprises a plurality of said orifices, and more preferably said blocks have said orifices of different shape, namely for example a cylindrical or frustoconical shape, preferably of circular section, or a shape of the prismatic type, that is to say polygonal cross section, square or rectangular, or a left surface hyperboloid type to a single sheet, such as a venturi.

In a preferred embodiment, said orifices have a porosity representing at least 50% of said overall porosity of said wall.

The term "block porosity" is understood to mean the percentage of void, that is to say the percentage of the empty surface created by said orifices relative to the total surface of a said block in vertical section.

According to another particular feature, said orifices have an axis in the perpendicular direction (YV) to said front and rear faces of said wall, but said axis can also be inclined.

The vertical and horizontal cables according to the invention may be made of steel, preferably of stainless steel, or of plastic or resistant composite material.

According to different variant embodiments adapted according to the implementation conditions of the device explained below:

said perforated blocks have identical porosities; or

said blocks of the same string of vertical cable have decreasing porosity from top to bottom; and preferably the lower terminal block is an unperforated block made of a concrete weighed down compared to that of the other blocks, or - Said blocks of the same string of vertical cable have a greater porosity in the upper part and lower than in the intermediate part.

Thus in one embodiment, said wall is constituted by an assembly of said vertical strings of different porosity variations so that along a said horizontal cable strand there are variations in block porosity between different parts. of said horizontal rosary.

In a preferred embodiment, said vertical cables are suspended from a beam or cable above the surface of the water and the lower end of at least the two vertical cable strings constituting the lateral edges of said wall. are anchored to anchored elements or placed at the bottom of the water or simply tensioned by weights.

In a variant that can be adapted to certain uses that need not to encumber the surface of the water in particular, the lower end of said vertical cables is moored to a lower beam or anchor cable attached to anchored elements or placed on the bottom water such as piles or moorings, and the upper ends of said vertical cables are tensioned by tensioning means such as stays or a top float.

In this last embodiment, preferably said blocks are made of lightweight concrete or plastic or composite material.

The present invention also provides a method for damping the swell and the chop, characterized in that a device according to the invention is immersed in a substantially vertical position.

More particularly, a said device is installed vertically below the pontoons preferably between two piles supporting them, more particularly still below mooring and landing pontoons, in a port facility.

Preferably, the device according to the invention is immersed so that:

the upper edge of said wall constituted by the upper faces of the blocks at the ends in the upper part of said vertical strings is flush with the surface of the water or reaches a height above or a depth below the surface of the water less than 1 m, and - The lower edge of said wall formed by the lower faces of the blocks at the lower ends of said vertical cable strings is located at least 0.5 m from the ground. Thus, the rocking movements, in the case of a device not moored at the bottom, does not interfere with the ground or any obstacle existing or reported later resting at the bottom.

In an advantageous embodiment, at least two rows of devices according to the invention are installed in parallel.

Compared to the conventional mass solutions of the prior art, the device according to the invention has the following advantages: small footprint in plan;

- lower installation cost;

- possibility of carrying out work progressively by progressively equipping the wharves on piles as and when the use of the water body changes;

lack of amplification of the stirring by reflection of waves of "long" period (with respect to the inertia of the curtain);

- Due to its flexibility, it can withstand extreme swells.

Other features and advantages of the present invention will become apparent in the light of the detailed description which follows, with reference to the following figures in which: FIG. 1 represents a front view of a damping device according to the invention installed in suspension below a pontoon θ between two piles 12 supporting the pontoon,

FIG. 2 is the front view of a unitary block having a self-locking shape on its upper and lower faces and cylindrical and frustoconical perforations passing through it,

FIG. 3 is the side view of a lateral face 4-2 of a block according to FIG. 2,

FIG. 4 is a sectional plan view according to AA of a block according to FIG. 2, FIG. 4a details a preferred notched version 4-6 of the lateral wall 4-1, 4-2 of said block,

FIG. 5 is a front view of the assembly of sheet blocks and presenting various variants of cylindrical 5-1 and frustoconical 5-2 and prismatic 5-3 perforations,

FIGS. 6a-6b-6c show a front view of the assembly of blocks of varied porosity, to form vertical cable strings whose porosity is uniform (FIG. 6a), or decreasing from top to bottom (FIG. ) or with a reduced porosity in a central part between the upper and lower ends (FIG. 6c), FIG. 7 is a front view of a variant of FIG. 1 in which the device is totally immersed and outcropped at the surface,

FIG. 8 shows a front view of a variant in which the device according to the invention is anchored to the sea bed and held in tension by a float (13). FIG. 9 is a side view showing the reduction of swell and chop when the water passes through the device from its front face 1-1 to its back 1-2.

In Figure 1 there is shown a pontoon consisting of an apron 9 resting on piles 12 anchored in the seabed 14 and supporting a device according to the invention, hereinafter also called "porous curtain" according to the invention, suspended by a multiplicity of vertical cables 2 to a 9-1 beam integral with said apron. Mooring cables 11-2 located at the bottom of the curtain 1 are connected to attachment points 12-1 integral with said stacks 12, thus maintaining the curtain in a substantially flat configuration, despite currents and waves to which it is submitted.

Figure 2 shows a front view of a unit block 4 constituting the porous curtain. It consists of a solid body preferably obtained by molding a resistant material, preferably a concrete and having on two opposite faces, respectively the upper lateral faces 4-3 and lower 4-4, complementary curves, c ' that is to say, substantially identical curves that allow the concave curve of the lower face 4-4 of a block to come to center on the convex curvature of the corresponding upper face 4-3 of the lower block. Each block is pierced from top to bottom, respectively from top to bottom 4-6 as shown on the sectional view of Figure 4 and horizontally from right to left 4-7 as shown. in Figure 3. These openings allow the passage of cables, the vertical cable ZZ axis 2 'for holding in suspension the assembled blocks in parallel vertical strings between them shown in Figures 6a-6c. The blocks of the same vertical strand rest directly on each other by gravity, a lower washer 8-2 being crimped at the bottom of said vertical string to retain the assembly. The horizontal openings 4-7 of axis XX 'allow the passage of a horizontal cable 3 in said blocks thus forming horizontal strings and to assemble all the vertical strings together to form the porous curtain 1.

The blocks are also drilled in their thickness along YY 'main orifices 5 in which will occur pressure drops that will mitigate the effects of the swell and currents passing through. These orifices 5 are open empty holes connecting the front face 4-8 of the block to its rear face 4-9, as shown in FIGS.

3-4. They are 5-1 cylindrical or frustoconical 5-2, circular or rectangular section or prismatic 5-3, or any intermediate shape. Their axis is preferably parallel to the axis YY ', to facilitate prefabrication mainly during demolding, but they may have an oblique direction relative to the XYZ mark.

These orifices 5 give the front faces 1-1 and rear 1-2 of the wall or curtain 1 a porosity having the effect of absorbing the kinetic energy of the water particles, either by friction on the walls, or by creating vortices, and thus damping the speed of said water particles, and thus reduce the speed of the currents or the amplitude of the swell and the dapot passing through them.

The front face 4-8 of said blocks is advantageously profiled to improve the transfer of the water flows to the various pressure drop orifices 5, either with a pointed shape as shown in FIG. 4, or with a convex curved shape (not shown) The lateral faces 4-1, 4-2 of the blocks are advantageously notched 4-5 to increase the roughness of the passage 7 between two adjacent blocks, as shown in FIG. 4a.

In Figure 5 there is shown in front view the assembly of two vertical and horizontal strings at two adjacent blocks. The suspension cable 2 passes vertically through the string of blocks, the horizontal cable 3 passes horizontally along XX 'to all the adjacent blocks, each of the blocks being separated from the next by a buffer 6 of controlled thickness, preferably made of elastomer, by neoprene example, which gives the whole a certain flexibility. A bushing 8-1 is crimped onto the cable at the left end 1-5 of the wall or curtain 1, in the same way a second bushing (not shown) is crimped at its right end 1-6, after the cable has been tensioned, which has the effect of compressing all elastomeric buffers to a uniform prestressing value. This gives a certain stiffness to the curtain while maintaining a certain flexibility conferring a deformation capacity to dampen the swell and chop In this figure, there are shown orifices of various shapes.

The empty spaces 7 between adjacent blocks on the same horizontal string and between two vertical strings side by side also contribute to the overall porosity of the curtain 1 as the orifices 5 but to a lesser extent.

Figures 6a-6b-6c shows rosaries having different porosities. The rosary of Figure 6a has a uniform porosity over the entire height. The string of Figure 6b has a decreasing porosity from top to bottom, the lower block 4-10 is opaque and consists of a very high density concrete, weighed for example by iron shot. The string of Figure 6c has a high porosity at the top and bottom, the intermediate portion 2-1 having a lower porosity. Depending on the configuration of the site to be protected, it will advantageously optimize damping by organizing the porosity rather, towards the surface, or downwards. To limit the phenomena of curtain resonance, in a non-uniform porosity configuration, several types of vertical strings, for example strings of the type of FIGS. 6a, 6b and 6c, will be advantageously alternated, so that along a horizontal generator is also found a variation of said porosity.

In a preferred version shown in FIGS. 7 and 9, more particularly intended for areas of low tidal range, the curtain is flush with the level of the water, so that a swell can cross said curtain, but, the flow of water passing through said curtain will create a phase shift of the wave which will have an attenuation effect of said wave, and this will result in a highly attenuated residual wave.

In a variant of the invention shown in Figure 8, the curtain is fixed on a lower beam 11-1 secured to anchor points such as the stacks 12, or dead bodies simply placed on the bottom. A float 13 located at the top of the curtain ensures its tensioning upwards and maintains it in a position substantially vertical. Complementary shrouds (not shown) preferably located in the YZ plane advantageously improve the vertical stability of said curtain. The curtain is then immersed so that its upper edge 1-3 reaches 0.5 to 1 m from the surface and does not clutter the surface which may be appropriate for certain use, in particular to protect a bathing area or a zone allowing low draft boats.

The unit blocks 4 are preferably made by casting heavy materials in the case of hanging curtains, and light in the case of curtains tensioned by a float, as described in FIG. 8. Among the heavy materials, concrete will advantageously be used, which will advantageously be increased to constitute the lower elements described in Figure 6b. Among the lightweight materials, it will be advantageous to use concretes with light aggregates, or combinations of concrete structure and plastics.

The vertical support cables 2 as well as the horizontal tensioning cables 3 of the curtains 1 will advantageously be made of stainless steel or of plastics material, such as polyethylene, polyamide or polyimide, or any other resistant fiber that is insensitive to plastics. 'water.

The dimensions of the blocks 4 will depend on the means of prefabrication and lifting means, they have 0.4m to 1.2 m wide, 0.6 to 2 m high and their thickness varies from 10 to 30 cm. The cylindrical or conical orifices according to the different cross-sectional variations, have an equivalent diameter (average cross section) of 8 to 25 cm, depending on the type of damping sought. To avoid splinters during handling and during their lifetime, the edges of the blocks are advantageously rounded, which facilitates their demolding, especially in the case of use of concrete for manufacturing.

Adjacent blocks on a horizontal cable 3 will be spaced 7 from 0.015m to 0.2m.

As an illustration, the curtain in FIGS. 7 and 8 has an overall porosity of 28.5%, each block pierced with orifices 5 having a porosity of 23.8%, all of said orifices 5 representing 71% of the overall porosity, the complement of porosity being provided by the empty spacer spaces 7 between adjacent blocks, the sections of the elastomeric pads 6 being opaque, as well as the mass of the blocks themselves. As a general rule, in order to fulfill their function of damping the propeller jets, the curtains must extend over the entire slice of water, but it is preferable to leave the lower edge 1-4 of the curtain at about 0.5 m. or Im from the sea floor, so that the rocking movements, in the case of a device not moored in the lower part, do not interfere with said ground or any obstacle existing or reported later.

The overall dimensions of the curtain 1 will advantageously be selected to respect the road templates, that is to say that said curtains will not exceed 2.5m in width, devices, not shown in the figures for assembling rigidly or hinged , two adjacent devices, so that they deform together under the effect of the jets of propellers, choppers or small swells.

The device of the invention is intended primarily to damp currents induced by the propeller jets and choppers and waves of ships, but it can be applied without technical limitation to medium or long swells. The period of separation between waves stopped and waves transmitted has indeed nothing absolute on the technical level. We can always increase the mass, the stiffness, the anchors, the porosity, etc. so that the device according to the invention is opposed to swells of any period.

The device according to the invention is at the same time:

- flexible to limit the internal forces under the effect of these solicitations, and also not to interact too much with swells of strong period, and

- High inertial mass, and preferably weigh when it is predated, to provide significant inertia hydrodynamic stresses targeted.

It is in principle simply hanging in the head on a fixed structure or strong inertia compared to the waves (floating platform for example), but it is also anchored advantageously also at the foot or at any other point.

In a preferred version of the invention, it is advantageous to install at least two rows, or even three or more, of devices according to the invention in parallel, said devices being more particularly at a distance from each other of a few meters.

In this case, advantageously, each of the rows has its porosity and its own rigidity, for example a first row with medium porosity, simply suspended but tensioned by a series of massive lower blocks of type 4-10, and a second row of low porosity uniformly distributed over the height, each of the devices being anchored to the foot and strongly tensioned to remain substantially plane, as shown in Figure 1.

Claims

1. Water movement damping device constituting a flexible wall (1) disposed in the water near the surface, substantially vertically in a static state of rest, comprising massive unit blocks (4) optionally perforated (5) assembled to each other in a string through cables (2,3) in which said blocks (1) are threaded or on which said blocks are crimped,

said cables comprising:

A first series of cables (2) arranged vertically (ZZ ⁷ ) side by side, parallel to each other, and a second series of cables (3) arranged horizontally (XXf) one above the other in parallel, and each block (4) is pierced (4-6, 4-7) from one side in the vertical direction (ZZ ') and in the horizontal direction (XXO _/ to allow the passage of at least one said vertical cable ( 2) and at least one said horizontal cable (3), and each said block is assembled to at least one said vertical cable thereby forming a plurality of parallel vertical cable strings (2), and at least a portion of said blocks, preferably each said block being assembled (s) to at least one said horizontal cable, thus ensuring the assembly of the different vertical cable strings between them, and

said vertical cables (2) being suspended or tensioned at their upper ends and / or respectively tensioned or moored at their lower ends, and

the blocks are assembled in a string with the upper faces of one against the lower faces of the others along said vertical cables (2), and

said blocks are spaced apart (7) from each other along said horizontal cables (3) by buffers (6), preferably made of elastomeric material, and preferably a sleeve (8-1) is crimped at each end of each horizontal cable (3) so that said buffers are compressed to a substantially uniform preload value, and said blocks comprise:

"empty orifices (5) passing right through them between the front (1-1) and rear (1-2) faces of said wall (1), and / or" empty spaces (7) between said blocks, such that said orifices (5) and / or empty spaces between said blocks (7) give said wall a global porosity preferably representing 5 to 75%, more preferably 20 to 45%, of the surface of the vertical section of the said wall. io

2. Device according to claim 1 characterized in that said blocks comprise upper faces (4-3) and lower (4-4), are of complementary shapes thus ensuring self-locking of said respective upper and lower faces of two adjacent blocks along of a said vertical cable.

3 Device according to claim 1 or 2 characterized in that the vertical cables are suspended and tensioned by the weight of all of said blocks resting on each other by gravity, the lower terminal block being held on the cable so as to retain all of said blocks of the same vertical cable.

4. Device according to one of claims 1 to 3 characterized in that at least part of said blocks has said orifices (5).

5. Device according to claim 4 characterized in that each block comprises at least one said orifice.

6. Device according to one of claims 4 or 5 characterized in that each block comprises a plurality of said orifices (5).

7. Device according to claim 6 characterized in that said blocks have said orifices (5) of different shapes.

8. Device according to one of claims 4 to 7 characterized in that said orifices (5) have a porosity representing at least 50% of said porosity of said wall.

9. Device according to one of claims 4 to 8 characterized in that said orifices (5) have a cylindrical (5-1) or frustoconical (5-2), preferably circular section, or a shape of the type of prismatic (5-3) square or rectangular section.

10. Device according to one of claims 4 to 9 characterized in that said orifices (5) have an axis in the direction perpendicular (YY ⁷ ) to said front (1-1) and rear (1-2) of said wall.

11. Device according to one of claims 4 to 10 characterized in that said perforated blocks have identical porosities.

12. Device according to one of claims 4 to 10 characterized in that said blocks of the same string of vertical cable (2) have a decreasing porosity from top to bottom.

13. Device according to claim 12 characterized in that the lower terminal block is a non-perforated block made of a concrete weighed compared to that of the other blocks.

14. Device according to one of claims 4 to 13 characterized in that said blocks of the same string of vertical cables (2) have a greater porosity in the upper part and in the lower part than in the intermediate part (2-1 ).

15. Device according to one of claims 12 to 14 characterized in that said wall is constituted by an assembly of said vertical cable strings (2) of different porosity variations so that along a said string of horizontal cable (3) there are variations of block porosity between different parts of said horizontal string.

16. Device according to one of the preceding claims characterized in that said vertical cables (2) are suspended from a beam (9-1) or support cable above the surface of the water (10) and the end lower than at least the two vertical cable strings constituting the lateral edges (1-4,1-5) of said wall (1) are moored to elements anchored or placed at the bottom of the water (14) or simply tensioned by weights.

17. Device according to one of claims 1 to 15 characterized in that the lower end of said vertical cables (2) is moored to a beam (11-1) or lower mooring cable (11-2) attached to anchored elements (12) or placed at the bottom of the water such as piles or Mooring, and the upper ends of said vertical cables are tensioned by tensioning means such as shrouds or an upper float (13).

18. Device according to claim 17 characterized in that said blocks are made of lightweight concrete, plastic or composite material.

19. Device according to one of claims 1 to 18 characterized in that: - said blocks have the following dimensions:

-0.4 to 1.2 m in width (XX ⁷ ) -0.6 to 2 m in height (ZZO io

-0.10 to 0.30 m thick (YY ¹ ) _/ and

- said orifices (5) have a diameter or average dimension in cross section (XX ', ZZO 0.08 to 0.25 m.

20. Process for damping the movements of water such as the currents induced by the propeller jets, the chop and the swell, characterized in that a device according to one of claims 1 to 19 is immersed in position. substantially vertical.

21. The method of claim 20 characterized in that a said device is installed in a port area, substantially vertically below the pontoons (9), preferably between two piles (12) supporting them.

22. The method of claim 20 or 21 characterized in that the device is immersed so that:

- The upper edge (1-3) of said wall formed by the upper faces (4-3) of the blocks at the ends in the upper part of said vertical cable strings (2) is flush with the surface of the water (10) or at a height above or a distance below the surface of the water of less than 1 m, and

- The lower edge (1-4) of said wall formed by the lower faces (4-4) of the blocks at the lower ends of said vertical cable strings is located at least 0.5 m from the ground.

23. Method according to one of claims 20 to 22, characterized in that at least two rows of device according to the invention are installed in parallel.