JPH11227683A - Rolling reducing structure of floating structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To generate a higher effect to reduce the rolling than in a conventional structure and allow easy maintenance and adjustment of the neutral condition of a floating structure. SOLUTION: A rolling reducing structure is equipped with a rolling reducing hollow body 7 on the side face 2x of a floating structure 2 on its wave W incident side, wherein the hollow body 7 is composed of an inclined plate 4, which is inclined to the upstream in the wave W advancing direction with the top located near the draft line 3 and whose bottom is positioned in depth near the undersurface of the floating structure 2, and a bottom plate 6 which extends from the bottom of the inclined plate 4 approx. horizontally toward the floating structure 2 and is provided with an opening 5 in an appropriate position.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure for reducing the rolling of a floating structure which is installed in a floating manner in a coastal area such as the sea and used for various purposes due to waves.

[0002]

2. Description of the Related Art In recent years, it has been considered that a coastal area can be effectively used, and large-scale convention facilities, parking lot facilities, and the like are manufactured as pontoon-type floating structures, and these are being installed in a floating manner. .

In order to utilize such floating structures in the coastal area in the same way as the above-ground structures, it is necessary to reduce the fluctuation caused by the waves as much as possible. Although mooring is performed at a fixed position in the area with a large number of chains and wire ropes, the fact is that swinging due to waves cannot be effectively reduced simply by increasing the number of chains and wire ropes.

[0004] In particular, in the case of a floating structure in a coastal area, FIG.
As shown in a plan view, a force of a wave W in a substantially constant direction is often applied from the offshore side to the floating structure 2 moored to the quay 1, and a rolling R (rolling) due to the wave W is generated. Reduction is the biggest challenge.

Accordingly, the applicant of the present invention has already filed Japanese Patent Application No. Hei.
No. -19145 has filed an effective rolling reduction structure of a floating structure. In the invention of this application, for example, as schematically shown in FIG. 5, a box-shaped floating body (pontoon)
It is proposed that the side surface 2x on the incident side of the wave W in the floating structure 2 provided as a shape inclined toward the upstream side in the traveling direction of the wave W.

In fact, by adopting such a shape, it is possible to reduce the wave forcing moment and the rolling amplitude of the floating structure 2 with respect to the rolling R, and it is possible to greatly reduce the rolling R by a water tank test. Has been confirmed.

[0007]

However, in the conventional structure of the prior application, since the rolling R is reduced by changing the shape of the floating structure 2 itself, the floating structure 2 is moved in the traveling direction of the wave W. And the extra buoyancy increases on the incident side of the wave W. Therefore, there is a difficulty in maintaining and adjusting the neutrality of the floating structure 2, and this makes it difficult for various devices on the upper surface of the floating structure 2. There was a problem that the arrangement was restricted.

The present invention has been made in view of the above-mentioned circumstances, and has a higher effect of reducing the roll than the conventional structure, and can easily maintain and adjust the neutrality of the floating structure. It is an object of the present invention to provide a roll reduction structure.

[0009]

SUMMARY OF THE INVENTION The present invention is directed to a wave-incident side surface of a floating structure, which is inclined toward the upstream in the direction of travel of the wave with the upper end near the waterline and the lower end of the lower surface of the floating structure. A tilting hollow body comprising a tilted plate reaching the vicinity and a bottom plate extending substantially horizontally from the lower end of the tilted plate toward the floating structure side and having an opening formed at an appropriate position is provided. The present invention relates to a structure for reducing the rolling of a floating structure.

In this manner, the overall shape of the floating structure including the hollow body is reduced so that the side face of the floating structure itself on the wave incident side is different from the conventional structure in the traveling direction of the wave. It is equivalent to the one inclined toward the upstream side,
As the wave forcing moment against rolling decreases,
The roll amplitude also decreases.

[0011] At this time, the water moves up and down due to the incidence of the wave on the lower side of the bottom plate in the hollow body, but the water freely enters and exits through the opening of the bottom plate. The body itself does not generate buoyancy, and when water enters and exits the opening in the bottom plate, a vortex is formed on the exit side of the water entry and exit, and a large damping force against rolling occurs. Become.

[0012]

Embodiments of the present invention will be described below with reference to the drawings.

FIGS. 1 to 3 show an embodiment of the present invention, in which the same reference numerals as in FIG. 5 denote the same parts.

As shown in FIGS. 1 and 2, in this embodiment, the vicinity of a water line 3 (a demarcation line where the floating structure enters the water) is formed on the side surface 2 x on the incident side of the wave W of the floating structure 2. An inclined plate 4 inclined toward the upstream side in the traveling direction of the wave W and having a lower end approaching the depth of the lower surface of the floating structure 2, and extending substantially horizontally from the lower end of the inclined plate 4 toward the floating structure 2 In addition, a vibration-reducing hollow body 7 including a bottom plate 6 having an opening 5 is provided near the side surface 2x of the floating structure 2 on the incident side of the wave W, and is substantially perpendicular to the traveling direction of the wave W. A triangular internal space 8 is formed when viewed from the horizontal direction.

Here, since the internal space 8 of the hollow body 7 extends in a horizontal direction substantially perpendicular to the traveling direction of the wave W and has both ends open to the outside, the bottom plate is provided. The structure is such that water freely enters and exits from the opening 5 formed in the hollow 6, so that the hollow body 7 itself does not generate buoyancy.

Further, since the vibration-reducing hollow body 7 has a plate-like structure composed of the inclined plate 4 and the bottom plate 6, the weight increase due to the provision of the vibration-reducing hollow body 7 is negligible. Compared with the floating structure 2 before the attachment, the amount of water drained by the above-mentioned slight weight increment (the weight of water eliminated by the submerged portion of the floating structure 2 when the floating structure 2 floats in still water and maintains equilibrium) : The product of the volume of the floating structure 2 below the water surface and the specific gravity of water) merely increases.

In the drawing, the upper end of the inclined plate 4 of the rocking hollow body 7 is aligned with the water line 3, but the upper end of the inclined plate 4 only needs to be located near the water line 3, for example, from the water line 3. Although it may be located slightly below, it is more effective to be located above the waterline 3 more preferably.

In this manner, the hollow body 7 is reduced.
And the entire shape of the floating structure 2 including the above is the same as the conventional structure in which the side surface 2x on the incident side of the wave W of the floating structure 2 itself is inclined toward the upstream side in the traveling direction of the wave W. ,
As a result, the wave forcing to the roll R is reduced, and the roll amplitude is also reduced.

At this time, the water moves up and down below the bottom plate 6 in the rocking hollow body 7 due to the incident wave W, and the water freely enters and exits the opening 5 of the bottom plate 6. Therefore, the hollow body 7 itself does not generate buoyancy, and when water enters and exits the opening 5 of the bottom plate 6, as shown by solid arrows and broken arrows in FIG. A vortex is formed on the exit side of the entrance and exit, and a large damping force against the roll R is generated.

Therefore, according to the above embodiment, the vibration-reducing hollow body 7
Can reduce the wave-forcing moment and the rolling amplitude of the floating structure 2 with respect to the rolling R as in the prior art, and at the same time, water can pass through the opening 5 of the bottom plate 6 of the hollow body 7. Since the damping force caused by moving in and out can also act synergistically, the effect of reducing the roll can be greatly improved as compared with the conventional structure.

Further, the hollow body 7 is composed of the inclined plate 4 and the bottom plate 6.
Since no extra buoyancy is generated and the weight increase by the provision of the hollow body 7 is small, the entire floating structure 2 including the hollow body 7 is formed. Even if the shape is asymmetric in the traveling direction of the wave W,
Neutrality of the floating structure 2 can be easily maintained and adjusted, thereby greatly reducing restrictions on the arrangement of various devices on the upper surface thereof, and particularly, maintaining neutrality of the existing floating structure 2 The present invention can be applied very easily without causing any particularly remarkable inconvenience regarding adjustment and restrictions on arrangement of various devices.

It is to be noted that the structure for reducing the roll of the floating structure of the present invention is not limited to the above-described embodiment, and it is needless to say that various changes can be made without departing from the gist of the present invention. is there.

[0023]

According to the above-mentioned structure for reducing the rolling of the floating structure of the present invention, various excellent effects as described below can be obtained.

(I) According to the outer shape of the hollow body,
The wave forcing and the roll amplitude for the roll of the floating structure can be reduced as before, and
Since the damping force caused by the ingress and egress of water through the opening of the bottom plate of the hollow body can also act synergistically, the effect of reducing the roll over the conventional structure can be greatly improved.

(II) Since the hollow anti-vibration body has a plate-like structure composed of an inclined plate and a bottom plate, no extra buoyancy is generated, and the weight increase due to the provision of the anti-vibration hollow body is small. Even if the entire shape of the floating structure including the anti-rolling hollow body is asymmetric in the direction of the wave propagation, the neutrality of the floating structure can be easily maintained and adjusted.
Restrictions on the arrangement of various devices on the upper surface can also be greatly eased, and it does not cause exceptional remarkable problems, especially regarding maintaining and adjusting the neutrality of existing floating structures and restricting the arrangement of various devices. Can be easily applied.

[Brief description of the drawings]

FIG. 1 is a perspective view schematically showing an example of an embodiment for carrying out the present invention.

FIG. 2 is a side view of FIG. 2;

FIG. 3 is an enlarged view illustrating movement of water flowing into and out of the rocking hollow body of FIG. 2;

FIG. 4 is a plan view showing an installation state of a floating structure in a coastal area.

FIG. 5 is a perspective view showing a conventional example.

[Explanation of symbols]

 Reference Signs List 2 Floating structure 2x Side of wave incident side 3 Waterline 4 Inclined plate 5 Opening 6 Bottom plate 7 Reduced hollow body R Rolling W wave

Claims (1)

[Claims] 1. An inclined plate having, on a side of a wave incident side of a floating structure, a slope inclined toward an upstream side in a traveling direction of a wave with a vicinity of a draft line as an upper end and having a lower end close to a depth of a lower surface of the floating structure. And a bottom plate having a bottom plate that extends substantially horizontally from the lower end of the inclined plate toward the floating structure and that has an opening at an appropriate position. .