PROPULSION DEVICE FOR A VESSEL, COMPRISING AT LEAST ONE HOLLOW WING HAVING A LONGITUDINAL AXIS INTENDED TO EXTEND VERTICALLY

Abstract

This relates to a propulsion device for a vessel, including at least one hollow wing which includes: an envelope which delimits an internal volume and which includes a rear part including two perforated zones; a suction device, to generate a flow of sucked air which is intended to pass through the perforated zones; and a shutter, adapted to alternately close one of the two perforated zones. The shutter includes: at least one shutter member which consists of a flexible flap, and an operator structured to operate the flexible shutter within the frame.

Description

TECHNICAL FIELD OF THE INVENTION

The present invention relates to the technical field of propulsion devices for vessels which comprise at least one wing having a longitudinal axis intended to extend vertically.

STATE OF THE ART

Environmental constraints, and the increase in the cost of fossil fuels, require vessel builders to propose partial alternatives to thermal engines.

In this sense, documents FR2847009 and FR3035861 describe wind thrusters which comprise an elongated hollow body, suction zones provided along the peripheral wall of this hollow body, and associated suction means.

The suction at the peripheral wall of the thruster makes it possible to limit the separation of the flow of the aeraulic flow from the wall of the thruster.

To produce a lift force directed to one side or the other of the vessel, these wind thrusters generally use a system of flaps which are movably mounted to respectively close off symmetrically arranged suction zones.

However, the orientation of the lift force is not always optimal with current flap systems.

Indeed, the shutting obtained with current shutter systems is not completely effective.

Suction phenomena are then likely to occur outside the initially planned suction zones, leading to a loss of efficiency of the suction means.

Therefore, there is a need for new wind thrusters whose orientation of the lift force and efficiency would be improved.

Presentation of the Invention

To remedy the aforementioned drawback of the state of the art, the present invention proposes a propulsion device for a vessel, comprising at least one hollow wing having a longitudinal axis intended to extend vertically.

This hollow wing includes:

• • an envelope which delimits an internal volume and which has a rear part comprising two perforated zones,

which two perforated zones are in fluid communication with said internal volume and are arranged symmetrically on either side of a longitudinal plane of symmetry,

• • suction means, to generate a flow of sucked air which is intended to pass through said perforated zones and which is directed towards said internal volume, and
  • shutter means, adapted to alternately close one of said two perforated zones, which shutter means include:
  • at least one shutter member, adapted to close at least one of said two perforated zones,
  • operating means, adapted to operate said at least one shutter member relative to at least one of said two perforated zones,

which operating means are structured to operate said at least one shutter member between two positions:

• • an open position, in which said at least one shutter member is retracted relative to at least one of said two perforated zones, and
  • a closed position, in which said at least one shutter member is deployed facing said perforated zone.

And said at least one shutter member consists of a flexible flap.

Said operating means comprise a frame equipped with support means which cooperate with said at least one flexible shutter.

And said support means are structured to maneuver said flexible flap within said frame between said two positions, advantageously without friction phenomena between said flexible flap and said envelope, namely:

• • said open position, in which said flexible flap is moved away from said envelope and retracted relative to at least one of said two perforated zones, and
  • said closed position, in which said flexible flap is deployed facing said envelope and conforms to (or fits) said perforated zone.

Such a structure offers a wind thruster whose orientation of the lift force and efficiency are improved compared to the state of the art.

Preferably, the support means comprise at least one rotary roller, which is maneuvered in translation around said envelope and which cooperates with said at least one flexible flap to define two strands: an active strand, intended to conform to said envelope, and an inactive strand, spaced from said envelope, which at least one roller advantageously comprises an axis of rotation which extends parallel to said longitudinal axis.

According to a preferred embodiment, said at least one flexible flap has two side edges, namely:

• • a fixed first side edge secured to said envelope, between said two perforated zones, and
  • a movable second side edge secured to said support means.

Other non-limiting and advantageous characteristics of this embodiment according to the invention, taken individually or in all technically possible combinations, are as follows:

• • said fixed first side edge is secured at the level of said longitudinal plane of symmetry;
  • the support means comprise at least one roller which consists of a return roller, cooperating with said at least one flexible flap to define the two strands: the active strand, extending between the first side edge and said return roller, and the inactive strand, extending between said return roller and said second side edge; the movable second side edge is advantageously secured to traction means which are movable in translation and which are intended to maintain said at least one flexible flap in tension; preferably, the shutting means comprise at least two flexible flaps intended to cooperate respectively with said two perforated zones, and the traction means consist of connecting means which connect the movable second side edges of said two flexible flaps;
  • the support means comprise at least one roller which consists of a winding roller, cooperating with said at least one flexible flap to define the two strands: the active strand, extending between the first side edge and said winding roller, and the inactive strand, wound around said winding roller, and of which said second side edge is secured to said winding roller;
  • the two side edges advantageously include rods and are assembled with complementary profiles.

Other non-limiting and advantageous characteristics of the product according to the invention, taken individually or in all technically possible combinations, are as follows:

• • the frame cooperates with motor means, for the translational maneuvering of said frame on the circumference of said envelope, and which maneuvering means are structured to coordinate, on the one hand, said translational movement of said frame and, on the other hand, said movement of said flexible flap between said open position and said closed position, advantageously without friction phenomena between said flexible flap and said envelope; preferably, the motor means comprise at least one motor member which is coupled with pinions, and at least one toothed ring gear, which are distributed between said casing and said frame;
  • the shutting means comprise at least two flexible flaps which are each intended to close respectively one of said two perforated zones;
  • said frame carries an aerodynamic flap, for example V-shaped, forming the trailing edge of said hollow wing;
  • said envelope comprises: a front part, forming the leading edge of the wing, and a rear part, provided with perforated zones;
  • said at least one flexible shutter is chosen from flexible membranes and rolling shutters.

The present invention also relates to a vessel equipped with a propulsion device according to the invention.

Of course, the different characteristics, variants and embodiments of the invention can be associated with each other in various combinations as long as they are not incompatible or exclusive of each other.

DETAILED DESCRIPTION OF THE INVENTION

In addition, various other characteristics of the invention emerge from the appended description made with reference to the drawings which illustrate non-limiting forms of embodiment of the invention and where:

FIG. 1 is a general perspective view of a vessel equipped with a propulsion device according to the invention;

FIG. 2 is an isolated perspective view of a hollow wing belonging to the propulsion device according to the invention;

FIG. 3 is a partial perspective view of a section of a hollow wing whose shutting means comprise two flexible flaps (flexible membranes) each cooperating with a return roller (also named deflection roller or guide roller);

FIG. 4 is a top view of the hollow wing section illustrated in FIG. 3;

FIG. 5 is a partial view of the hollow wing section according to FIG. 4, illustrating the shutting means in more detail;

FIG. 6 is an isolated and perspective view of the shutter means illustrated in FIGS. 3 to 5;

FIG. 7 is a partial perspective view of a section of a hollow wing whose shutting means comprise two flexible flaps each cooperating with a winding roller;

FIG. 8 is a partial view of the hollow wing section according to FIG. 7, illustrating the shutting means in more detail;

FIG. 9 is an isolated and perspective view of the shutter means illustrated in FIGS. 7 and 8;

FIG. 10 is a partial perspective view of a section of a hollow wing whose shutting means comprise two flexible flaps (rolling shutters) which each cooperate with a return roller (also named deflection or guide roller);

FIG. 11 is an isolated and perspective view of the shutter means illustrated in FIG. 10.

It should be noted that, in these figures, the structural and/or functional elements common to the different variants may have the same references.

The present invention thus relates to a propulsion device 1 for a vessel N (FIG. 1).

By “vessel” is meant in particular a boat (or ship) intended for maritime navigation, preferably large tonnage, decked boats intended for transport at sea, preferably cargo vessels.

The propulsion device 1 according to the invention comprises at least one hollow wing 2, preferably several hollow wings 2, which is erected on the vessel N.

The hollow wing 2 according to the invention is intended to generate a lift force which is used to participate in the propulsion of the vessel N. Thus, the hollow wing 2 is of the wind type and is mounted on the vessel N so that the air flow passes around this hollow wing 2 to generate a propulsive force.

Generally speaking, such a hollow wing 2 has a longitudinal axis 2′ intended to extend vertically.

As shown in FIG. 2 and following, the hollow wing 2 comprises:

• • an envelope 3 which delimits an internal volume 31 and which comprises two perforated zones 32,
  • suction means 4 (represented schematically in FIG. 2), to generate a flow of sucked air which passes through the perforated zones 32 and along the internal volume 31, and
  • shutting means 5, adapted to alternately closing the perforated zones 32 (taking into account in particular the orientation of the air flow passing around the hollow wing 2).

Envelope

The envelope 3 is for example made of a material chosen from steel, aluminum or a composite material.

Preferably, the envelope 3 has a cross section, perpendicular to the longitudinal axis 2′ and horizontal, having an oval or elliptical shape.

Generally speaking, this envelope 3 advantageously comprises two front parts 3a, 3b:

• • a rear part 3a, and
  • a front part 3b, advantageously forming a leading edge of the hollow wing 2.

In other words, the two parts 3a, 3b extend longitudinally and over the height of the envelope 3, on either side of the longitudinal axis 2′.

Each one of the two parts 3a, 3b advantageously has a section in the shape of a semi-oval or semi-circle, separated by a small axis passing through the longitudinal axis 2′.

The envelope 3 also has two longitudinal ends 3c, 3d, defining its height (FIG. 2):

• • a lower longitudinal end 3c, intended to be fixed to the vessel N and to be oriented downwards, and
  • an upper longitudinal end 3d, opposite, intended to be oriented upwards and away from the vessel N.

The envelope 3 also includes two opposite surfaces 3e, 3f (FIG. 3 and following):

• • an interior surface 3e, delimiting the internal volume 31, and
  • an exterior surface 3f, opposite, oriented outwards and participating in generating the lift force.

Furthermore, preferably, the rear part 3a of the envelope 3 comprises the two perforated zones 32.

The two perforated zones 32 are in fluid communication with the internal volume 31.

Each perforated zone 32 advantageously comprises a plurality of through orifices, allowing circulation of an air flow.

The through orifices thus open advantageously at the level of the two opposite surfaces 3e, 3f of the envelope 3.

The perforated zones 32 are thus intended to be crossed by a flow of air, flowing between the internal volume 31 and the exterior (between the two opposite surfaces 3e, 3f of the envelope 3).

The two perforated zones 32 are also arranged symmetrically on either side of a longitudinal plane of symmetry P of the envelope 3 (FIG. 3).

Each perforated zone 32 advantageously extends over the entire height of the envelope 3, on one side of the longitudinal plane of symmetry P of the envelope 3.

Here again, the upper longitudinal end 3d of the envelope 3 is terminated by a terminal wing 35 extending in a plane perpendicular to the longitudinal axis 2′. This terminal wing 35 makes it possible to stabilize the air flow and limit turbulence at the top of the envelope 3.

This wing 35 includes in particular a V-shaped leading edge, extending cantilevered on either side of the envelope 3.

Suction Means

The suction means 4, illustrated schematically in FIG. 2, are designed to generate a flow of sucked air which is able to pass through the perforated zones 32.

The suction means 4 then generate a flow of sucked air which is directed towards the internal volume 31, from the outside.

In other words, the flow of sucked air travels from the exterior surface 3f, towards the interior surface 3e, of the envelope 3.

For this, the suction means 4 advantageously comprise a fan having an axis of rotation which is parallel to the longitudinal axis 2′ of the hollow wing 2.

The fan is advantageously installed connected to the internal volume 31 and at the level of the lower longitudinal end 3c of the envelope 3.

Shutting Means

The shutting means 5 are adapted to alternatively close one of the two perforated zones 32, to create lift.

As shown in FIG. 3 and following, the shutter means 5 include:

• • at least one shutter member 51, adapted to close at least one of said two perforated zones 32,
  • operating means 52, adapted to operate said at least one shutter member 51 relative to at least one of said two perforated zones 32, which comprise a frame 521 equipped with support means 522 cooperating with said at least one flexible shutter 51.

In this case, said at least one shutter member 51 here consists of a flexible flap 51.

Generally speaking, said at least one flexible flap 51 is advantageously chosen from:

• • the flexible membranes 51 (FIGS. 3 to 9), for example made of a material chosen from neoprene rubbers, polyurethanes, polyester elastomers, which can be woven or non-woven, and
  • the rolling shutters 51 (FIGS. 10 and 11), comprising a plurality of pivoting blades 511 (for example made of plastic, metallic or composite material).

The width of the pivoting blades 511 is advantageously chosen as a function of the diameters of the exterior surface 3f of the envelope 3 (and, where appropriate, of said at least one roller 5221 described subsequently).

Two pivoting blades 511 are advantageously connected by a hinge structure, allowing a degree of freedom in rotation advantageously parallel to the longitudinal axis 2′.

Preferably, the shutting means 5 comprise at least two flexible flaps 51 which are intended to cooperate respectively with the two perforated zones 32.

In other words, the shutting means 5 comprise at least two flexible flaps 51 which are each intended to close respectively one of said two perforated zones 32.

For this, these flexible flaps 51 are then advantageously located on either side of the longitudinal plane of symmetry P.

In other words, each flexible flap 51 is intended to close one of the two perforated zones 32:

• • a first flexible flap 51 is intended to close a first perforated zone 32, on a first side of the plane of longitudinal plane of symmetry P of the envelope 3, and
  • a second flexible flap 51 is intended to close a second perforated zone 32, on a second side of the plane of longitudinal plane of symmetry P of the envelope 3.

Furthermore, said at least one flexible flap 51 advantageously comprises two side edges, namely:

• • a fixed first side edge 51d, secured to the envelope 3, between the two perforated zones 32, and
  • a mobile second side edge 51e, secured to the support means 522.

Preferably, the two side edges 51d, 51e comprise rods 51j and are assembled with complementary profiles 5225 belonging to the support means 522.

For example, the first fixed side edge 51d is secured to a complementary profile 5225d which is fixed to the envelope 3. Preferably, the first, fixed side edge 51d is secured at the longitudinal plane of symmetry P.

The mobile second side edge 51e is intended to be maneuvered so as to maneuver said at least one shutter member 51 relative to a perforated zone 32.

Generally speaking, the operating means 52 are structured to operate said at least one shutter member 51 between two positions:

• • an open position (illustrated for example in FIG. 3), in which said at least one shutter member 51 is retracted relative to at least one of said two perforated zones 32 (here relative to the perforated zone 32 which is at the bottom in FIG. 3), and
  • a closed position (illustrated for example in FIG. 3), in which said at least one shutter member 51 is deployed facing said perforated zone 32 (here on the perforated zone 32 which is located at the top in the FIG. 3).

And the support means 522 are structured to maneuver the flexible flap 51 within the frame 521 between the two positions, namely:

• • the open position, in which the flexible flap 51 is moved away from the envelope 3 and retracted relative to at least one of said two perforated zones 32, and
  • the closed position, in which the flexible flap 51 is deployed facing the envelope 3 and conforms to (also named fits) a perforated zone 32.

Generally speaking, said at least one flexible shutter 51 is protected within the frame 521, in the open position, in the closed position and when maneuvering between these two positions.

Preferably, the support means 522 are structured to maneuver the flexible flap 51 within the frame 521, between the two aforementioned positions, without friction phenomena between this flexible flap 51 and the envelope 3. In other words, the flexible shutter 51 is maneuvered, between the two aforementioned positions, without sliding phenomenon relative to the envelope 3.

Such a structure is particularly interesting for limiting, or even eliminating, the phenomena of wear by friction of the flexible flap 51 on the surface of the envelope 3 during maneuvers between the two aforementioned positions.

For this, the support means 522 advantageously comprise at least one rotary roller 5221, which is maneuvered in translation around the envelope 3.

This translation maneuver is advantageously carried out according to a stroke matching the envelope 3, and in particular its rear part 3a.

This roller 5221 cooperates advantageously with said at least one flexible flap 51 to define two strands:

• • an active strand 51a, intended to conform to the envelope 3, and
  • an inactive strand 51b, separated from this same envelope 3.

Said at least one roller 5221 advantageously comprises an axis of rotation 5221′ which extends parallel to the longitudinal axis 2′ of the hollow wing 2.

Likewise, the frame 521 cooperates advantageously with motor means 524 (schematic in FIG. 4), for the translational maneuver of the frame 521 on the circumference of the envelope 3.

The motor means 524, distributed between the envelope 3 and the frame 521, comprise for example:

• • at least one motor unit which is coupled with pinions, and
  • at least one toothed ring.

The frame 521 then follows a trajectory which is also parallel to the envelope 3, advantageously on an angular sector of the rear part 3a.

In this context, the support means 522 are advantageously structured to coordinate, on the one hand, the translational movement of the frame 521 and, on the other hand, the movement of the flexible flap 51 between the open position and the closed position.

This coordinated movement advantageously makes it possible to avoid friction phenomena between the flexible flap 51 and the envelope 3.

In this case, advantageously, the evolution of the length dimension of the active strand 51a is synchronized with the evolution of the displacement dimension of the frame 521.

For this, in particular, the rotary roller 5221 is advantageously fixed within the frame 521. The movement of the roller 5221 is then caused by the movement of this frame 521 which is controlled here by the motor means 524.

Furthermore, in general, the frame 521 carries an aerodynamic flap 5211, for example V-shaped, forming the trailing edge of the hollow wing 2.

The aerodynamic flap 5211 makes it possible to break the symmetry of the envelope 3 and thus increase the propulsive force generated.

This aerodynamic flap 5211 is oriented on one side or the other of the envelope 3, relative to the longitudinal plane of symmetry P of the envelope 3, depending on the direction of the wind.

The flow of fluid around the hollow wing 2 is then accelerated on one side and slowed down on the other side, which reinforces the propulsive force.

Embodiments

According to a first embodiment described below in connection with FIG. 3 to 6 or 9 and 10, the support means 522 comprise at least one roller 5221 which consists of a return roller 5221 (also named deflection roller or guide roller), cooperating with said at least one flexible flap 51 to define the two strands:

• • the active strand 51a, extending between the first side edge 51d and the return roller 5221, and
  • the inactive strand 51b, extending between the return roller 5221 and the second side edge 51e.

Preferably, the flexible flap 51 has a general dihedral shape, on either side of the return roller 5221.

In this first embodiment, the movable second side edge 51e is advantageously secured to traction means 525 which are movable in translation, and which are intended to maintain said at least one flexible flap 51 in tension.

More preferably, the traction means 525 consist of connecting means 525 which connect the movable second side edges 51e of the two present flexible flaps 51.

The connecting means 525 advantageously consist here of links 525a (for example metal cables) passing through return pulleys 525b.

These links 525a are advantageously equipped with a spring member 525c, aimed at controlling the tension forces.

According to a second embodiment described below in connection with FIGS. 7 to 9, the support means 522 comprise at least one roller 5221 which consists of a winding roller 5221.

Said at least one winding roller 5221 cooperates with said at least one flexible flap 51 to define the two strands:

• • the active strand 51a, extending between the first side edge 51d and the winding roller 5221, and
  • the inactive strand 51b, wound around the winding roller 5221, and of which said second side edge 51e is secured to this winding roller 5221.

Said at least one winding roller 5221 is for example rotated by:

• • a spring member, ensuring a winding return, or
  • a gear.

Generally speaking, each embodiment can include a flexible shutter 51, advantageously chosen from flexible membranes 51 and rolling shutters 51.

Functioning

In practice, the shutting means 5 are maneuvered around the hollow wing 2 to alternately close one of the two perforated zones 32 depending on the direction of the air flows and so as to create lift.

In this case, the closed position has the advantage of offering a configuration in which said at least one flexible flap 51 is deployed facing a perforated zone 32 and pressed against the envelope 3, to obtain optimal closing and to eliminate (or at least significantly limit) leaks.

At the same time, the suction means 4 are implemented to generate a flow of sucked air which is able to pass through the “free” perforated zone 32 with respect to the shutting means 5.

More precisely, the flexible flap 51 is advantageously moved from its open position to its closed position, by the implementation of the operating means 52. In the presence of two symmetrical flexible flaps 51, the second flexible flap 51 follows a movement reverse, from its closed position to its open position.

During this movement towards the closed position, the flexible flap 51 is advantageously maneuvered so that its active strand 51a gradually extends from its movable roller 5221.

In this case, according to the first embodiment, the first flexible flap 51 undergoes a translation movement relative to the first movable roller 5221 so that its active strand 51a lengthens at the same time as its inactive strand 51b shrinks.

For this, the movement of the frame 521 causes a movement of the first roller 5221 which moves away from the first, fixed side edge 51d and which presses the first flexible flap 51 against the first perforated zone 32.

At the same time, the second flexible flap 51 undergoes a translation movement relative to the second movable roller 5221 so that its active strand 51a decreases at the same time as its inactive strand 51b lengthens.

For this, the movement of the frame 521 causes a movement of the second roller 5221 which approaches the fixed first side edge 51d.

According to the second embodiment, the first flexible flap 51 undergoes an unwinding movement relative to the first movable roller 5221 so that its active strand 51a lengthens at the same time as its inactive strand 51b shrinks.

For this, the movement of the frame 521 causes a movement of the first roller 5221 which moves away from the first fixed side edge 51d, and from which the first flexible flap 51 unfolds.

At the same time, the second flexible flap 51 undergoes a winding movement relative to the second movable roller 5221 so that its active strand 51a decreases at the same time as its inactive strand 51b winds up.

For this, the movement of the frame 521 causes a movement of the second roller 5221 which approaches the fixed first side edge 51d.

In practice, in the case where the direction of the wind is incident on the hollow wing 2 of a first side of the envelope 3 which has a first perforated zone 32, the shutter means 5 are operated so that this first perforated zone 32 is closed by said at least one flexible flap 51.

In this closed position, said at least one shutter flap 51 is deployed facing this first perforated zone 32 and pressed against the envelope 3.

This closed position ensures optimal closing of this facing first perforated zone 32.

The second perforated zone 32 (on the second side of the envelope 3) is then free, generating the flow of air sucked through this second perforated zone 32.

In this case, the support 53 in the form of an aerodynamic flap is also oriented at the first side of the envelope 3.

The fluid flow around the hollow wing 2 is then further accelerated on one side and slowed down on the other side, which further increases the propulsive force.

Of course, various other modifications can be made to the invention within the scope of the appended claims.

Claims

1. Propulsion device for a vessel, comprising at least one hollow wing (2) having a longitudinal axis (2′) intended to extend vertically, which hollow wing (2) comprises: an envelope (3) which delimits an internal volume (31) and which comprises a rear part (3a) comprising two perforated zones (32),which two perforated zones (32) are in fluid communication with said internal volume (31) and are arranged symmetrically on either side of a longitudinal plane of symmetry (P), suction means (4), for generating a flow of sucked air which is intended to pass through said perforated zones (32) and which is directed towards said internal volume (31), andshutter means (5), adapted to alternately close one of said two perforated zones (32),which shutter means (5) comprise: at least one shutter member (51), adapted to close at least one of said two perforated zones (32),operating means (52), adapted to operate said at least one shutter member (51) relative to at least one of said two perforated zones (32),which operating means (52) are structured to operate said at least one shutter member (51) between two positions: an open position, in which said at least one shutter member (51) is retracted relative to at least one of said two perforated zones (32), anda closed position, in which said at least one shutter member (51) is deployed facing said perforated zone (32),wherein said at least one shutter member (51) consists of a flexible flap (51),wherein said operating means (52) comprise a frame (521) equipped with support means (522) which cooperate with said at least one flexible flap (51),and wherein said support means (522) are structured to maneuver said flexible flap (51) within said frame (521) between said two positions, namely: said open position, in which said flexible flap (51) is spaced from said envelope (3) and retracted relative to at least one of said two perforated zones (32), andsaid closed position, in which said flexible flap (51) is deployed facing said envelope (3) and conforms to said perforated zone (32).

2. The propulsion device according to claim 1, wherein the support means (522) comprise at least one rotary roller (5221), which is maneuvered in translation around said envelope (3) and which cooperates with said at least one flexible flap (51) to define two strands: an active strand (51a), intended to conform to said envelope (3), andan inactive strand (51b), spaced from said envelope (3).

3. The propulsion device according to claim 1, wherein said at least one flexible flap (51) has two side edges, namely: a fixed first side edge (51d) secured to said envelope (3), between said two perforated zones (32), anda movable second side edge (51e) secured to said support means (522).

4. The propulsion device according to claim 2, wherein said at least one flexible flap (51) has two side edges, namely: a fixed first side edge (51d) secured to said envelope (3), between said two perforated zones (32), anda movable second side edge (51e) secured to said support means, and wherein the support means (522) comprise at least one roller (5221) which consists of a return roller (5221), cooperating with said at least one flexible flap (51) to define the two strands:the active strand (51a), extending between the first side edge (51d) and said return roller (5221), andthe inactive strand (51b), extending between said return roller (5221) and said second side edge (51e).

5. The propulsion device according to claim 4, wherein the movable second side edge (51e) is secured to traction means (525) which are movable in translation and which are intended to maintain said at least one flexible flap (51) in tension.

6. The propulsion device according to claim 2, wherein said at least one flexible flap (51) has two side edges, namely: a fixed first side edge (51d) secured to said envelope (3), between said two perforated zones (32), anda movable second side edge (51e) secured to said support means, and wherein the support means (522) comprise at least one roller (5221) which consists of a winding roller (5221), cooperating with said at least one flexible flap (51) to define the two strands:the active strand (51a), extending between the first side edge (51d) and said winding roller (5221), andthe inactive strand (51b), wound around said winding roller (5221), and of which said second side edge 51e is secured to said winding roller (5221).

7. The propulsion device according to claim 1, wherein the frame (521) cooperates with motor means (524), for the translational maneuvering of said frame (521) on the circumference of said envelope (3), and which operating means (52) are structured to coordinate, on the one hand, said translational movement of said frame (521) and, on the other hand, said movement of said flexible shutter (51) between said open position and said closed position.

8. The propulsion device according to claim 1, wherein the shutting means (5) comprise at least two flexible flaps (51) which are each intended to respectively close one of said two perforated zones (32).

9. The propulsion device according to claim 1, wherein said frame (521) carries an aerodynamic flap (5211) forming the trailing edge of said hollow wing (2).

10. The propulsion device according to claim 1, wherein said envelope (3) comprises: a front part (3b) forming the leading edge of the wing, anda rear part (3a) provided with perforated zones (32).

11. The propulsion device according to claim 1, wherein said at least one flexible shutter (51) is chosen from flexible membranes (51) and rolling shutters (51).

12. Vessel equipped with a propulsion device according to claim 1.

13. The propulsion device according to claim 1, wherein said support means (522) are structured to maneuver said flexible flap (51) within said frame (521) between said two positions, without friction phenomena between said flexible flap (51) and said envelope (3).

14. The propulsion device according to claim 2, wherein said at least one roller (5221) comprises an axis of rotation (5221′) which extends parallel to said longitudinal axis (2′).

15. The propulsion device according to claim 7, wherein operating means (52) are structured to coordinate, on the one hand, said translational movement of said frame (521) and, on the other hand, said movement of said flexible shutter (51) between said open position and said closed position, without friction phenomena between said flexible flap (51) and said envelope (3).