JPS62215839A - Experimental water tank - Google Patents

Abstract

PURPOSE:To perform water tank experiment under a proper contraction percentage, by providing an experimental water tank set to a shallow water layer while providing a deep water layer having a depth capable of simulating the large depth of water of the ocean roughly to the central part of the bottom part of said tank. CONSTITUTION:In some sea area, there is a strong tide equal to or more than that of the surface layer of the sea in the intermediate depth-of-water region between the surface layer and bottom of the sea and large force is applied to the riser tube connecting the drilled well of the sea bottom and the drilling ship on the sea according to circumstances. In order to analyze the motion of this riser tube, a simulated tide generating apparatus 50 capable of generating a simulated tide M by stepwise changing a flow speed in a depth direction to the intermediate depth-of-water region of the deep water layer 13 of an experimental water tank 11 is provided. In this tide generating apparatus 50, a large number of partitions formed in a state divided in the depth direction to the opposed side surfaces of the deep water layer 13 and one of the opposed partitions are set to stream feeding distribution chambers 28 and the other to stream receiving distribution chambers 32 and a water recirculation line is provided so as to make the quantity of water variable at every the depth of water.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an experimental aquarium capable of conducting model experiments regarding marine structures directly connected to the seabed at great depths.

[Traditional technique]

Conventional experimental aquariums have a shallow water layer with a maximum depth of about 6 e; therefore, aquarium experiments are currently conducted using models with a scale appropriate to this water depth.

However, for models related to marine structures that are directly connected to the seabed at deep water depths exceeding 1ooo<=, if the large water depth is simulated to match the water depth of a general experimental tank, the scale of the model will be extremely large. The small size makes it difficult to match with actual equipment, and there is a limit to the miniaturization of various sensors, so there is a problem that experiments cannot actually be carried out in a general experimental tank with a shallow water layer.

In order to solve this problem, if the entire experimental water tank was made deeper, the construction cost would be high and a huge amount of water would be required.

[Purpose of the invention]

The present invention was devised in view of the above-mentioned conventional circumstances and to solve these problems.The deep water layer provided at the center of the bottom of the experimental tank makes it possible to conduct tank experiments simulating large water depths. The purpose is to provide an experimental aquarium.

[Structure of the invention]

An experimental aquarium according to the present invention that achieves the above object includes an experimental aquarium with a shallow water layer, and a deep water layer having a depth capable of simulating the deep water of the ocean at approximately the center of the bottom of the experimental aquarium. It is characterized by:

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, drawings showing the present invention as an embodiment will be described.

In the future, it is predicted that cheaper tilting platforms and tension mooring platforms will be used as platforms for oil production in deep water (water depths of 1000ζ or more) instead of conventional steel jackets.

All of these have the advantage that, unlike a steel jacket, they allow movement within a predetermined range against waves and currents, reducing stress acting on each part of the platform and reducing costs.

For deep-sea tilting platforms that move in response to waves and currents, it is necessary to understand their movements in detail.

As shown in FIG. 4, the tilting platform 10 is
In general, it is configured to be tiltable by a flexible joint 3 such as a universal joint provided on a base 2 installed on the seabed 1, while a large buoyant body 5 is provided just below the sea surface 4, and the moment when it tries to tilt due to its own weight. A moment acts against it and tries to keep it upright, preventing it from tilting more than a slight inclination.

Although the aforementioned tension mooring platform is not shown, the semi-submersible floating body is forcibly submerged slightly, and the semi-submersible floating body and the base on the seabed are connected by flexible vertical mooring legs. It is designed so that a large tension is always applied to the legs.

Both occupy almost the same area all the way to the ocean floor, and are only moved within a certain range by external forces.

Furthermore, below a certain water depth, the influence of ocean waves disappears. Furthermore, since they are generally installed at great depths where the influence of tidal currents disappears as the water depth increases, a deep water layer capable of simulating great water depths is required, but a wide experimental aquarium surface is not required.

Therefore, the experimental water tank 11 has a water depth of 2 to 4 i! ;(maximum 6ζ
) and a deep water layer 13 installed approximately in the center of the bottom 12. The depth of this deep water layer 13 is configured to a depth that can simulate the great depth of the ocean.

In other words, the scale ratio of the model often adopted as a model of this type of marine structure is 1150 to 1/100, and the deep water layer 1
When the depth of 3 is 20 packages, 20ζ;X (50-100) = 1000-2000
e; becomes. That is, when the depth of the deep water layer 13 is 20ζ, it is possible to simulate a water depth of 1000 to 2000e in the ocean.

In addition, the size of the horizontal cross section of this deep water layer 13 is 4 to 6 in diameter in the case of a circle; and 4 to 6 in one side in the case of a square
It is good if there is.

A wave-making device 15 is installed in the shallow water layer 14 of the experimental water tank 11, and a wave-dissipating device 16 is installed in the opposite case.

Since the tilting type bluff 1 to form IO shown in FIG. 4 are bottom-mounted, they are strongly affected by submarine earthquakes. Therefore, in experimental water +1'J11, deep water Ff
By installing a model excitation tM18 on the bottom 17 of the 13, and installing a platform model 20 thereon via a model flexible joint 19, various experiments under earthquake conditions can be carried out. This platform model 20 includes a float part 22 as a buoyant body just below the water surface 21, a tower part 23 that connects the float part 22 and the lower model flexible joint 19, and a deck part 25 above the float part 22. It is composed of a column section 24 that connects the two. This platform model 20 tilts in the direction of the arrow around the flexible joint 19 on the lower side, so the deep water layer 13 that houses it is narrow at the bottom and gradually widens (in an inverted conical shape) toward the top. Alternatively, the deep water layer 13 may be divided into a plurality of stages so that the upper part becomes wider.In addition, when this deep water layer 13 is not used, the upper part of the deep water layer 13 is closed off.

Furthermore, even on tension moored platforms, the mooring legs are greatly affected by earthquakes, so it is effective to understand the conditions under earthquakes.

Next, FIG. 2 will be explained. The system shown in FIG. 2 is designed to allow motion analysis of riser pipes and the like of drilling ships destined for deep water using the deep water layer 13. A particular problem is that depending on the sea area, there are tidal currents that are stronger than those at sea in the mid-water depth area between the ocean and the seabed, and these tidal currents can exert a large force on the riser pipe that connects the drilling valve on the seabed and the offshore drilling vessel. This may lead to destruction.

In order to analyze the movement of this type of riser tube,
A simulated tidal current generator 50 is attached that can generate a simulated tidal current M by changing the flow velocity stepwise in the depth direction in the intermediate depth area of the deep water layer 13 provided in 1. A plurality of compartments divided in the depth direction are provided on opposing sides of the deep water layer 13, and one of the opposing compartments is used as a flow distribution chamber 28 and the other as a flow distribution chamber 32 for receiving water, and the amount of water is variable depending on the water depth. A water circulation line is installed so that

That is, the tidal current on the ocean can be simulated in the shallow water layer 14 by the main circulation line 27 by the main circulation pump 26. As shown in FIGS. 3A and 3B, the simulated tidal current M in the intermediate water depth region is transmitted from one side of the flow distribution chamber 28 provided at opposing positions in the deep water layer 13 to a large number of buckle plates 29.
A sub-circulation line 36 is provided, which passes through the deep water 513 through a large number of opening holes 30 while being rectified by the flow, and flows into the receiving distribution chamber 32 via a large number of opening holes 31 provided on the other side. In this case, the cross section of the deep water Fi 13 may be circular or square.

Further, as shown in FIG. 2, the aforementioned distribution chamber 28 and distribution chamber 32 are each divided into a plurality of areas by a large number of partition walls 33 arranged at predetermined intervals in the vertical direction,
By controlling the flow rate using the flow rate adjustment valve 34 of each of the 28 distribution chambers, it is possible to reproduce the distribution of tidal current velocity depending on the water depth. It is connected to a sub-circulation line 36 that connects the distribution chamber 32 and the distribution chamber 28.

In FIG. 2, a drilling ship model 40 is moored in the shallow water layer 14 of the experimental water tank 11 between a stopper 41 fixed to the bottom 12 by an anchor line 45 consisting of a spring 42, a pulley 43, etc. It is also possible to approximate the behavior of an anchor line at great depths.

A drill ship model 40 on the water surface 21 and a ball joint 47 fixed to a base 46 installed at the bottom 17 of the deep water layer 13
are connected by a model riser pipe 48, and the simulated tidal flow M
A motion analysis experiment of the model riser tube 48 can be performed using the following method.

In addition, recently, dynamic position holding systems (DPS) that do not use anchor lines have been increasingly adopted in deep water, but in this case, the experimental water tank 11
The drilling ship model 40 is attached to a trolley (not shown) attached to the drilling ship model 4 through a rocking device (not shown).
0 can also be given a rocking motion.

As described above, by providing the deep water layer 13 at the bottom 12 of the experimental aquarium 11 with a depth that can simulate the great depths of the ocean,
It is possible to conduct aquarium experiments using a model of a marine structure directly connected to the ocean floor at an appropriate scale. By providing a partial deep water layer 13 in the center of the bottom without deepening the entire experimental tank, it is possible to reduce the construction cost and minimize the amount of water required for the experimental tank. It has the advantage of being able to

In addition, as in the embodiment, on opposite sides of the deep water layer 13,
When the simulated tidal current generator 50 is attached, the deep water layer 13
Using the simulated tidal current M generated within the vessel, it is also possible to perform motion analysis regarding tidal currents of riser pipes, etc. of drilling ships destined for deep water.

〔Effect of the invention〕

In short, the experimental aquarium according to the present invention has an experimental aquarium with a shallow water layer, and a deep water layer with a depth that can simulate the great depths of the ocean at approximately the center of the bottom of this experimental aquarium. Although it is possible to conduct aquarium experiments using a model of a marine structure directly connected to the seabed at great depths at an appropriate scale, it is also possible to conduct a deep-water layer only in the center without deepening the entire experimental aquarium. By providing such a water tank, it is possible to suppress the cost increase of the construction q, and also to minimize the amount of water required for the experimental water tank.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention, in which Fig. 1 is a vertical cross-sectional view of an experimental aquarium having a deep water layer, and Fig. 2 is a longitudinal sectional view of an experimental aquarium with a simulated tidal current generator attached to the deep water layer. 3A and 3B are cross-sectional views of FIG. 2, and FIG. 4 is a side view of the tilting platform. DESCRIPTION OF SYMBOLS 11... Experimental water tank, 12... Bottom, 13... Deep water layer, 14... Shallow water layer, 50... Simulated tidal current generator, M... Simulated tidal current.

Claims (1)

[Scope of Claims] 1. An experimental water tank comprising a shallow water layer, and a deep water layer having a depth that simulates the great depths of the ocean at approximately the center of the bottom of the experimental tank. Aquarium. 2. The experimental aquarium according to claim 1, wherein a simulated tidal current generator is attached to opposing sides of the deep water layer.