JPH0530877A - Structure for generating upswelling flow - Google Patents

Abstract

(57) [Summary] [Purpose] A mound that can efficiently generate upwelling currents in all directions even in areas where the flow direction is not stable and that can be easily installed on the seabed. Provide a structure for upwelling in the form of a strip. [Structure] As a substantially cone-shaped or substantially truncated cone-shaped mound-like structure 10 provided with a gently sloping surface 14 that is inclined from a top portion 13 in a radial direction toward a seabed 12, a seabed 1
Install in 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an upwelling structure, and more particularly to a upwelling structure installed as a mound-like structure on the seabed.

[0002]

2. Description of the Related Art A so-called upwelling current, which flows from the seabed toward the sea surface, promotes vertical mixing of seawater by raising deep-seawater that tends to stagnant because of low water temperature and high specific gravity. In addition, nutrient salts such as phosphates and nitrates, which are abundant in the seabed, are pushed up to the upper layer where sunlight reaches, thereby promoting photosynthesis by sunlight and promoting plankton growth, and at the same time, to the surface layer of deep cold seawater. Due to the pressure difference and the temperature difference due to the increase, the dissolved amount of oxygen is increased, and these forms a favorable environment for the fish to inhabit. Therefore, if a vertical upwelling can be generated by utilizing a horizontal current such as an ocean current or a tidal current, its utility value is high, and various structures that generate upwelling from such a horizontal current have been developed. ..

As an example of such an upwelling generation structure, there is a mound-like upwelling generation structure described in Japanese Patent Application No. 3-67455 filed by the applicant of the present application. Due to the gentle slope, the upwelling flow can be generated more efficiently than the partition-type upwelling flow generation structure that is a known technique before that. That is, as shown in FIG. 4, this structure 30 has a ridge portion 31 arranged across the tidal current Y, and gentle sloping surfaces 32, 33 that incline from the ridge portion 31 toward the sea bottom,
The reciprocating flow passing across this runs up the inclined surface 32 and merges with the horizontal flow above the ridge 31, strengthening the horizontal flow and reducing the counterflow area in front of the structure, and further sloping the side edge. The surface 33 engulfs the flow passing thereabove, thereby efficiently generating the upwelling flow 34.

[0004]

However, the mound-like upwelling structure 30 having the above-described structure has a clear flow direction such as a reciprocating flow, and the structure 3 crosses the direction.
It is effective for sea areas where it is easy to set 0,
For example, in a sea area in which the flow direction frequency distribution as shown in FIG. 5 is not stable, as shown in FIG.
When a flow occurs in parallel with the direction of, the above-mentioned action cannot be obtained, and therefore, as shown in FIG.
There was a problem that the upwelling could not be generated efficiently.

When a mound-shaped structure is piled up with mound materials such as stones, blocks, coal ash concrete blocks, etc., it is necessary to construct a structure having a predetermined length while moving the position where the mound material is charged. was there.

Therefore, the present invention has been made to solve the above-mentioned problems, and an object thereof is to enable an upwelling current to be efficiently generated in an arbitrary flow direction even in a sea area where the flow direction is not stable. To provide a mound-like upwelling structure.

Another object of the present invention is to construct a mound material such as abandoned stone, a block, a coal ash concrete block, etc., which is piled up and installed in the sea. The object is to provide a mound-like upwelling structure having excellent properties.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned object, and its gist is a mound-like structure to be installed on the seabed to generate upwelling current. However, the upwelling generation structure is characterized in that it is installed as a substantially conical or substantially frustoconical structure having a gently sloping surface sloping toward the sea bottom in a radial direction from the top.

Here, the apex does not have to be an apex, but can be a flat surface such as a circle or a curved surface such as a spherical surface. And from the said top part, the inclined surface which inclines radially is provided, and by this, the mound-shaped structure has a substantially triangular or trapezoidal cross-sectional shape with respect to an arbitrary vertical cut surface.

The slope of the inclined surface is 1: 1.5 to 1:
It is preferably 3. If the gradient is larger than 1: 1.5, it is difficult to carry out the construction in deep water, and if the gradient is smaller than 1: 3, the upwelling flow generation efficiency is deteriorated and at the same time the volume of the structure is increased, which is preferable. Absent. Furthermore, the height of the structure is preferably 10% to 30% of the water depth of the installation sea area. If the height is lower than 10% of the water depth, nutrient salts cannot be sufficiently sent to the euphotic layer, and if it is higher than 30%, the upwelling effect is sufficiently exerted but the volume of the structure becomes very large, which is uneconomical. Therefore, both are not preferable.

Although the upwelling structure may be integrally formed of concrete, steel structure, etc., it is constructed by stacking mound materials such as abandoned stones, blocks, and coal ash concrete blocks at an arbitrary scale. Preferably.

[0012]

In the mound-like upwelling structure of the present invention,
The flow colliding with the radially expanding inclined surface rises up the inclined surface and produces a vertical vortex due to the action of the negative pressure region generated on the back surface of the structure, and the flow passing through the laterally expanding inclined surface is the inclined surface. Change the direction inward by the action of, and the flow passing through the side of the structure is attracted to the center by the action of the negative pressure area on the back of the structure and collides with each other, thereby efficiently upwelling It will occur. In addition, since the upwelling structure has a sloping surface that extends radially around the top, it faces each other with the same shape in all flow directions, and therefore its efficiency is reduced by the same action for all flow directions. No upwelling occurs.

Further, in the upwelling structure of the present invention, when the mound material such as abandoned stone, block, coal ash concrete block, etc. is piled up and installed, the structure has a substantially conical shape or a substantially truncated cone shape. It has a shape, and since such a shape is similar to the shape formed as a result of natural dropping after the material is put into the sea from the same location, its construction is facilitated.

[0014]

Embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

As shown in FIGS. 1 (a) and 1 (b), in the upwelling structure of this embodiment, a mound material 11 such as abandoned stone, a block, a coal ash concrete block, etc. is piled up on the seabed 12. It is installed on the seabed as a mound-shaped structure 10 having a substantially conical shape. That is, the mound-shaped structure 10 has a spherical top portion 13 and an inclined surface 14 that is inclined from the top portion 13 in a radial direction toward the seabed ground 12 at an inclination of about 1: 2.

The mound-like structure 10 is 15 in the sea.
Then, the upflow is generated by acting on the flow X passing therethrough as follows. That is, the flow a colliding near the center of the mound-shaped structure 10 runs up the inclined surface 14, and a vertical vortex 17 is generated by the action of the negative pressure region 16 generated on the back surface of the mound-shaped structure 10.
Further, the flow b passing above the inclined surface 14 that spreads to the side of the structure 10 changes its direction inward by the action of the inclined surface that inclines outward, and further passes through the side of the mound-shaped structure 10. The flowing flows c are attracted to the center by the action of the negative pressure region 16 on the back surface of the mound-shaped structure 10 and collide with each other. And due to these synergistic effects, high upwelling 1
8 efficiently occurs. Here, the mound-shaped structure 10 as such an upwelling flow generation structure has the inclined surface 14 extending in the radial direction with the apex 13 as the center, and faces the flow from all directions in the same shape. The upwelling current 18 can be generated without reducing the efficiency with respect to the current direction.

In order to stack and mount the mound material 11 on the mound-shaped structure 10, for example, as shown in FIG.
A floating body device 20 provided with a cylindrical body 22 connected to the charging opening 21 and having a circular lower end is moored in a predetermined sea area, and the mound material 11 transported to the floating body device 20 by a grab boat 23 or the like is loaded. throw into. The charged mound material 11 drops in the sea and deposits on the bottom of the sea, forming a mound-like structure 10
To form. Here, the mound-shaped structure 10 to be installed
Since the mound material 11 has a conical shape, when the mound material 11 is thrown into the sea from the same location, it is similar to the shape formed by deposition as a result of spontaneous fall, and therefore, the mound material 11 can be easily moved without moving the loading location by the floating body device 20. The structure 10 can be formed. By making the tubular body 22 of the floating body device 20 expandable and contractable, the distance between the bottom opening and the seabed can be adjusted to arbitrarily set the slope of the inclined surface and the shape of the top.

FIG. 3 shows the inclination of the conventional type and the conical or truncated cone type mound-shaped upwelling generation structure shown in FIG. 4 in an experimental tank having a water depth of 25 cm and a flow rate of 3.5 cm / sec. It is a model shape-upwelling efficiency figure which shows the result of having performed the comparative experiment to the thing whose surface gradient is 1: 2. Here, the upwelling efficiency is a value obtained by dividing the upwelling amount upwelling at a predetermined water depth or more by the volume of the mound-like structure, when the flow goes in a direction perpendicular to the conventional mound-like structure. 1
It is the ratio calculated as 00%. In the right half of the figure, the horizontal axis is the angle from the direction perpendicular to the conventional upwelling structure, and the left half of the figure is the conical or frustoconical upwelling structure. The abscissa represents the shape of the top of the flow generating structure. And from such experimental results, the conventional type has a large upwelling effect when the flow direction is predominant in one direction, but the upwelling efficiency deteriorates as the flow direction varies, and therefore the upflow frequency distribution It is understood that, when considering multi-directionality in a sea area where a certain amount of variation occurs, for example, the total upwelling effect over a long time of one day or more is greater in a conical or frustoconical upwelling structure. It

[0019]

INDUSTRIAL APPLICABILITY As described above, the upwelling structure of the present invention is a mound-like structure of a substantially conical shape or a substantially truncated cone shape having an inclined surface that is inclined from the top toward the sea bottom in the radial direction. Since it is installed on the seabed as an object and faces the same direction with respect to all flow directions, it is possible to efficiently generate high upwelling current without being influenced by the direction of the flow even in the sea area where the flow direction is unstable. it can.

When the mound material is piled up to install the upwelling structure, its shape approximates to the shape formed as a result of the natural fall of the mound material in the sea, and the introduction and installation of the mound material. Since it is easy to construct, it can be easily constructed.

[Brief description of drawings]

FIG. 1 is an explanatory view showing an embodiment of an upwelling flow generation structure of the present invention, (a) is a side view, and (b) is a plan view.

FIG. 2 is an explanatory diagram showing an embodiment in which mound materials are stacked and an upwelling structure is installed.

FIG. 3 is a upwelling efficiency diagram showing a comparison of upwelling effects of conventional and inventive mound-like upwelling structures.

FIG. 4 is a perspective view showing a conventional mound-like upwelling generation structure.

FIG. 5 is a distribution chart showing an example of the frequency of flow direction in a sea area where the flow direction is not fixed.

FIG. 6 is an explanatory diagram showing a situation in which a flow occurs in parallel with a conventional mound-like upwelling structure,
(A) is a plan view and (B) is a side view.

[Explanation of symbols]

 10 Mound-like structure (upwelling structure) 11 Mound material 12 Submarine ground 13 Top 14 Slope

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Goro Isayama 2-5-8 Kitaoaoyama, Minato-ku, Tokyo Ma Incorporated

Claims (1)

Claim: What is claimed is: 1. A mound-like structure that is installed on the seabed to generate upwelling current, the structure sloping in a radial direction from the top toward the seabed. An upwelling generation structure, which is installed as a substantially conical or substantially frustoconical structure having a surface.