Submerged object suspended from a towing cable optimized to neutralize disrupting hydrodynamic forces

Patent metadata

Field	Value
Publication number	US-10029765-B2
Application number	US-201515515579-A
Country	US
Kind code	B2
Filing date	Oct 1, 2015
Priority date	Oct 1, 2014
Publication date	Jul 24, 2018
Grant date	Jul 24, 2018

Abstract

An object that can be towed in a fluid by a cable along a substantially horizontal transport axis comprises a body suspended under gravity from the cable by a fixing arm, and an exterior hydrodynamic surface that is symmetric with respect to a vertical plane containing the transport axis, so as to limit the lateral lift of the body, and an opening passing through the body along a vertical axis and configured to equalize the pressures of fluid flowing along the exterior surface, making it possible to limit the hydrodynamic forces that may be generated perpendicular to the transport axis giving rise to a force in rotation about the transport axis opposing the effect of gravity.

First claim

The invention claimed is:

1. An object intended to be towed in a fluid by a cable along a substantially horizontal transport axis; the object comprising a single-shell monocoque body and at least one fixing arm, the body being intended to be suspended under the effect of gravity from the cable by means of said at least one fixing arm,
the object wherein the body comprises:
an exterior hydrodynamic surface that is symmetric with respect to a vertical plane containing the transport axis so as to limit the lateral lift of the body,
a central opening passing through the body along a vertical axis, which opening is intended to be occupied by the fluid so as to equalize the pressures of fluid flowing along the exterior surface, so as to limit the vertical lift of the body;

making it possible to limit the hydrodynamic forces that may be generated perpendicular to the transport axis by the flow of fluid around the body and that are liable to lead to a load in rotation about the transport axis by opposing the effect of gravity.

2. The object as claimed in claim 1 , wherein the fixing arm has a shape that is asymmetric with respect to the vertical plane containing the transport axis.

3. The object as claimed in claim 2 , wherein the fixing arm has the overall shape of a “C”, connected by a first end to the body and intended to be connected by a second end to the cable.

4. The object as claimed in claim 2 , comprising a ballast weight positioned inside the body and configured so that the center of gravity of the object maintained at zero speed in the fluid is positioned in the vertical plane containing the transport axis.

5. The object as claimed in claim 4 , comprising a ballast weight positioned inside the body and configured so that the center of gravity of the object kept immersed in air at zero speed is positioned in the vertical plane containing the transport axis.

6. The object as claimed in claim 1 , comprising a ballast weight positioned inside the body and configured so that the center of gravity of the object is positioned in the vertical plane containing the transport axis both when the object is kept submerged at zero speed in water and when the object is kept immersed at zero speed in air.

7. The object as claimed in claim 3 , comprising a set of deflectors secured to the body configured to generate a hydrodynamic force by the flow of fluid around the object that neutralizes the hydrodynamic force induced by the asymmetric shape of the fixing arm.

8. The object as claimed in claim 1 , wherein the exterior surface comprises an upper surface and a lower surface which are symmetric with respect to one another about a horizontal plane so as to limit the vertical lift of the body.

9. The object as claimed in claim 1 , wherein the exterior surface comprises an upper surface and a lower surface, the upper surface or the lower surface is configured so as to form in the vertical plane containing the transport axis a thick NACA-type profile making it possible to limit the vertical lift of the body.

10. The object as claimed in claim 1 , wherein the exterior surface is configured so as to form in the horizontal plane a thick NACA-type profile making it possible to limit the lateral lift of the body.

11. The object as claimed in claim 1 , wherein the exterior surface is configured to form, in a vertical plane perpendicular to the transport axis, a curved profile, comprising a small vertical portion so as to limit the lateral lift of the body.

12. The object as claimed in claim 1 , wherein the exterior surface comprises an upper surface and a lower surface, the upper surface being configured so that the exterior surface forms:
in the horizontal plane a thick NACA-type profile making it possible to limit the lateral lift of the body;
in a vertical plane containing the transport axis, a thick NACA-type profile making it possible to limit the vertical lift of the body,
the opening on the one hand onto the upper surface and on the other hand onto the lower surface.

13. The object as claimed in claim 1 , wherein the body comprises a lateral opening passing through the body along a horizontal axis perpendicular to the transport axis and situated in a downstream part of the body so as to limit the lateral lift of the body, the opening being intended to be occupied by the fluid.

14. The object as claimed in claim 1 , comprising a substantially vertical aileron fixed on a downstream part of the body having a substantially asymmetric hydrodynamic shape configured to stabilize the orientation of the object by generating a moment about a vertical axis.

15. The object as claimed in claim 1 , comprising a substantially horizontal aileron fixed on a downstream part of the body having a substantially asymmetric hydrodynamic shape configured to stabilize the orientation of the object by generating a moment about the transport axis.

16. The object as claimed in claim 1 , comprising two fixing arms configured so as to connect, in first and second substantially vertical directions respectively, the cable and, respectively, a first and a second end of the body along the transport axis, so that a force tending to separate the two fixing arms makes it possible to stabilize the body about a vertical axis.

17. The object as claimed in claim 1 , intended for sonar detection in a marine environment, and comprising an acoustic emission antenna fixed to an internal structure of the body.

18. An active sonar system intended to be towed by a ship, comprising a towing cable that can be connected to the ship and an object as claimed in claim 1 , towed by the cable.

19. The active sonar system as claimed in claim 18 , comprising a tail containing a longilinear body for receiving acoustic signals.

20. The object as claimed in claim 1 , wherein the body is wholly delimited by a shell.

21. The object as claimed in claim 20 , wherein the shell comprises an exterior surface delimiting a volume that forms a single hydrodynamically profiled cell.

22. The object as claimed in claim 1 , wherein the body has the overall shape of a teardrop.

23. The object as claimed in claim 1 , wherein the exterior surface is substantially convex.

24. The object as claimed in claim 1 , wherein the dimension of the body along a vertical axis is substantially the same over the entire periphery of the opening.

Assignees

• Thales Sa
• Jourdan Michael

Inventors

• Jourdan Michaël
• Borel Christophe

Classifications

• B63B21/66 Primary

  Equipment specially adapted for towing underwater objects or vessels, e.g. fairings for tow-cables ({paravanes for dragging fishing nets A01K73/02; } salvaging underwater vessels or objects B63C7/00; towed underwater vessels B63G8/42) · CPC title

• B63B2211/02

  Oceanography · CPC title