TWI435971B - Artificial sea-mount - Google Patents

Description

Artificial seamount

The present invention relates to an artificial seamount that is constructed on the seabed to stimulate vertical mixing of seawater near the depth of compensation.

Background of the invention

At present, there is a technique for artificially constructing a seabed-shaped structure on the seabed, and the use of natural energy of currents or ocean currents to raise the nutrient salt rich in the seawater under the compensation depth to the sunlight. The surface area of the sea where the phytoplankton grows (compensation depth). It is known that this structure is used to produce phytoplankton that enriches seawater near the artificial seamounts with nutrients and provides fish and shellfish for reproduction. In this specification, this structure will be represented by an artificial seamount. The artificial sea-mount mountain is formed by stacking a plurality of blocks which are recyclable materials such as coal ash, concrete blocks, artificial blocks using waste materials, or natural blocks made of stones or the like. Made of body (the following is a block).

In order to achieve the desired inrush current through the artificial sea-mount mountain range, it is necessary to establish a large-scale artificial sea-bottom mountain range in the deep sea area. However, due to the difficulty of shrinking, artificial seamounts thus create a need to minimize the scale, and to produce an optimum inrush effect near the depth of compensation, i.e., to obtain vertical mixing of seawater.

Artificial seamounts of this type are described in U.S. Patent No. 5,267,812 (reference 1). Reference 1 describes an example of an artificial sea-mount mountain having a ridge formed by linearly connecting a pair of vertices of a cone disposed at a predetermined height in a vertical direction to traverse a tidal current. Reference 1 also illustrates another example of an artificial sea-mount mountain that connects the ridges of the vertices of a pair of cones below the vertices. In the second artificial sea-mount mountain range, the water that climbs up the slope and rapidly moves away from the horizontal line of the ridge of the artificial sea-mount mountain will form a vortex with a horizontal axis and, at the same time, move around the side surface of the artificial sea-mount mountain and The stream that is quickly removed from there will form a vortex with a vertical axis. These two vortices are combined in a counterflow region formed behind the artificial sea-mount mountain to intermittently generate large surge vortices.

Current field observations and analysis reveal that in deep sea areas with strong density stratification, the wavelength and height of the internal waves formed vary according to water depth, current state, stratum state, and the height and shape of the artificial seamount. In addition, it is known that since the direction and speed of the water flow eventually change due to the influence of tide retreat and tidal current, the wavelength and wave height of the internal wave temporarily change. "Density stratification" means a continuous density layer structure which is formed by surface water having a low density due to high temperature and low salt concentration, and deep water having a low temperature and a high salt concentration.

In general, seawater is difficult to mix vertically in a density stratified state. However, it is known that internal waves generated by collisions of water currents with subsea structures or the like can cause vertical mixing, even in the vicinity of the surface layer. Therefore, there is a need for an efficient artificial seamount that can cause vertical mixing in the deep sea where the water mass density varies greatly between the surface and the bottom layer and includes the vertical distribution of density and nutrients. There are various changes in water conditions.

To effectively generate horizontal vortices under water conditions with no or weak density stratification, the artificial seamounts of reference 1 form a horizontal ridge that moves linearly in a direction substantially perpendicular to the flow of water, thereby forming a surge vortex. However, according to the test of the inventor of the present invention, no significant inrush vortex was observed in the deep sea area with strong density stratification. It is known that when the density is strongly stratified, a large amount of seawater at the bottom layer easily passes over a structure to effectively generate internal waves, which strongly stimulates vertical mixing.

summary

It is an object of the present invention to provide an artificial seamount that can cause effective vertical mixing, even in deep sea areas with intense density stratification.

In order to achieve the above object, according to the present invention, there is provided an artificial sea-mount mountain range which is constructed by stacking a plurality of blocks on a seabed, which uses tides and currents in a marine area where the plurality of blocks are stacked. And internal waves for vertically mixing seawater in the surrounding marine region, including a first array of cones formed by the plurality of blocks, and comprising at least three cones linearly arranged on the seabed, The apex spacing between the cones adjacent to each other is set to be 0.75 to 2 times the radius of the bottom of the cone.

According to the invention, the apex spacing between the three or more cones of the artificial seamount is set to be 0.75 to 2 times the radius of the bottom of the cone. Due to the inverted triangular gap formed between the cones and the plurality of conical surfaces, a composite water flow or vortex is generated by the tidal current, ocean current or internal wave colliding with the artificial seamount and across it. This composite water flow or vortex produces internal waves that rise above the upstream to the downstream of the artificial seamount and their effects are further transmitted upwards. To this end, effective vertical mixing can be induced near the depth of compensation, even in deep sea areas with continuous intense density stratification. This vertical mixing can enrich the water present under the compensation depth to the water above the compensation depth, thereby making the water zone rich in nutrients.

According to the present invention, changing the vertex spacing between the cones of the artificial seamount can quickly create vertices from the composite water flow and cause more efficient vertical mixing. Constructing an artificial seamount group by arranging most of the artificial seamounts can also lead to more efficient vertical mixing.

As is well known in the past, artificial seamounts not only have the above-described vertical mixing function, but are also greatly provided as a fishing bank. Regarding the function of fisheries, it is known that artificial seamounts should have hidden places of various sizes for the accumulation of fish and shellfish to protect them from hazards, such as large-scale migratory fish. In addition, it is desirable to provide an adherent base material with excellent seawater exchange so that microorganisms feeding the aggregated fish and shellfish can adhere to the surface of the block and grow. The artificial sea-mount mountain of the present invention can obtain about 20% more surface area and more complex shapes than the artificial sea-mount mountain range described in Reference 1 in the same volume (assuming that the structural cost is proportional to the bulk volume). Large food microbes can be grown due to the ability to disperse light and water and provide many effective attachment surfaces.

On the other hand, the relevant configuration, such as the mountain having a continuous linear ridge in the horizontal direction in Reference 1, needs to be constructed by constantly fine-tuning the falling position of the block. However, the artificial seamount can be easily and efficiently constructed in the deep sea by centering the vertex positions and shapes of the cones of the mountain to handle the vertex position and height as desired by the design. In addition, the number of cones and the vertex spacing can be changed in the design of the artificial sea-mount mountain to make the artificial sea-mount mountain have the smallest volume and meet the required total surge flow while maintaining the high flow per unit volume. effectiveness.

Simple illustration

1A and 1B are a perspective view and a front view of an artificial sea-mount mountain range according to a first embodiment of the present invention; and FIG. 2 is a chart showing a relationship between a cone and a surge flow of an artificial sea-mount mountain range according to the first embodiment. Fig. 3 is a graph showing the relationship between the vertex spacing and the surge flow between the cones of the artificial sea-mount mountain range according to the first embodiment; and Fig. 4 is the artificial sea-mount mountain range according to the modification of the first embodiment. 5A and 5B are perspective and front views of an artificial sea-mount mountain range according to a second embodiment of the present invention; and FIG. 6 is a view showing a relationship between vertex spacing and inrush flow of an artificial sea-mount mountain range according to the second embodiment. 7A and 7B are perspective views of an artificial sea-mount mountain range according to a modification of the third embodiment of the present invention; FIG. 8 is a front view of the artificial sea-mount mountain range according to the fourth embodiment of the present invention; and FIG. It is a graph showing the relationship between the distance between adjacent artificial sea-mount mountains and the inrush flow according to the fourth embodiment.

Detailed description of the preferred embodiment (First Embodiment)

A first embodiment of the present invention will now be described with reference to Figs. 1A through 3.

As shown in Fig. 1A, an artificial sea-mount mountain M1 is formed by three cones C1, C2 and C3 (conical columns) having a circular base and being nearly perpendicular to the tidal current, ocean current and interior in the sea area. The directions of the waves are arranged linearly. The trailing ends of the adjacent cones C1, C2 and C3 are in contact with each other or overlap, which will be described in detail later to form a mountain shape. It should be noted that the bases of the cones C1, C2 and C3 may not be circular and may have a shape that is nearly circular. In this embodiment, the cones C1, C2, and C3 are formed to have the same size and shape and have the same apex height H and the same bottom radius r. In fact, they can have slight differences. The vertex spacing L between adjacent cones C1, C2 and C3 is set to be 0.75 to 2 times its bottom radius r.

More specifically, in order to construct an artificial sea-mount mountain range at a depth of about 160 m on a continental reef layer, if each cone has a height H=20 m and an inclination H/r=1/2 to ensure its stability on the seabed. Degree, assuming radius r = 40 m and vertex spacing 1.25 = 50 m.

For example, to construct the artificial sea-mount M1, a work boat such as a bottom-hopper barge is positioned at a first position on the sea to continuously drop a predetermined number of blocks and The piles are piled up on the seabed to form the cones C1. Next, the work boat is moved away from the second position, one of two times the vertex spacing between the cones, and positioned so that the block can be placed and stacked on the seabed a predetermined number of times to form the cone C3. The cone C2 is then formed in the same manner at a third location between the cones C1 and C3.

It should be noted that the order of the cone architecture is not limited to this. It should be noted that this structure does not have a precise cone shape at the portion where the adjacent cones overlap in FIG. 1A. However, it is important to reach a predetermined vertex spacing and vertex height. Especially in the deep sea, due to the strong action of the ocean currents, the placed blocks will drift until they are placed on the seabed. Controlling the position of the placement to accurately position the blocks at the apex of each cone provides an architecturally accurate configuration.

According to the artificial sea-mount mountain M1 of the first embodiment, a three-dimensional gap having a complex inverted triangular surface is formed between the vertices of the cones C1, C2 and C3. In addition to this, all of the tail surface, that is, the side of the artificial sea-mount mountain M1, is a conical surface. Therefore, a tidal current or ocean current perpendicular to the direction in which the cones C1, C2, and C3 are arranged will collide with the artificial seamount M1, and the water flow obscured by the structure will follow the cones C1, C2, and C3. The uniform tail surface rises. This rising water flow passes over the artificial seamount M1 to create a composite water flow or vortex, and at this point causes effective internal waves.

If the spontaneously generated internal waves collide with the artificial seamount M1, it is expected that the internal waves can be broken and rapidly mixed in the artificial sea-mount M1. The manner in which the vortex generated by the artificial sea-mount M1 is different from that in the case of having no or low-density stratification in Reference 1 is different. A change in the flow or vortex caused by the flow of water across the artificial seamount M1 can produce an effective internal wave from upstream to downstream of the artificial seamount M1. Since the influence of internal waves is transmitted upwards and upstream/downstream, effective vertical mixing can be caused even in deep sea areas with strong density stratification.

Fig. 2 is a simulation result showing the perturbation flow per unit volume of the artificial sea-mount mountain in Fig. 1 (hereinafter, simply expressed by the inrush flow), which is formed by a linearly arranged cone to make the tail thereof Overlap or touch each other. Gushing flow means that the nutrient salt passes vertically through a horizontal cross-section at various depths throughout the flow calculation area. To obtain the inrush flow, a marker of nutrient concentration is set to linearly increase from the surface layer to the bottom layer, and is averaged over a long period of time by the amount of mark that moves vertically through each horizontal cross section.

Figure 2 is a view showing the number of linearly arranged cones increased from 1 to 5 and six spacings L between adjacent vertices, i.e., 0.5 times (0.5r) of the radius r of the conical bottom, as shown in Fig. 1A. The inrush flow rate obtained by 1 time (1r), 1.25 times (1.25r), 1.5 times (1.5r), 2 times (2r), and 3 times (3r). In this simulation, the inrush current is higher than the level obtained in Reference 1 is set to a low threshold (=0.625). In this case, the inrush flow rate of the present embodiment exceeds the threshold when the number of cones is three or more, and L=1r to 2r, as seen in FIG.

Fig. 3 is a graph showing the simulation results of the surge flow when the number of cones is limited to 3 to 5 to reduce the number of blocks of the artificial sea-mount mountain range, and the vertex distance L between adjacent cones is changed. According to this simulation, if the vertex spacing L is less than 0.75r or greater than 2r, the inrush flow is less than the low threshold (=0.625). On the other hand, when L = 0.75 to 2r, the inrush flow rate is greater than the low threshold (=0.625). In particular, the surge flow is the maximum when L = 1.25r.

In the first embodiment, the three cones are linearly arranged while partially overlapping. From the simulation results, it can be seen from Figures 2 and 3 that the inrush flow rate can be exceeded by using three or more cones. Therefore, as shown in Fig. 4, an artificial sea-mount mountain M2 can be formed by linearly arranging four cones C1 to C4. Although not shown, five or six or more cones may be linearly arranged. In any case, the vertex spacing L is preferably set in the range of 0.75r to 2r.

(Second embodiment)

Next, the artificial sea-mount mountain range according to the second embodiment will be explained with reference to Figs. 5A to 6 . The main configuration is the same as that of the first embodiment. In the second embodiment, from the cones C1, C2 and C3 of the artificial sea-mount M3, the vertex spacing La between the cones C1 and C2, and the vertex spacing between the cones C2 and C3 Lb is different. It is to be noted that the height H and the bottom radius r of the respective cones C1, C2 and C3 are the same as in the first embodiment. The vertex spacings La and Lb fall within the range of 0.75r to 2r as in the first embodiment.

Fig. 6 is a graph showing the simulation results of the inrush flow rate obtained by changing the ratio La/Lb of the vertex spacings La and Lb in the range of 0.5 to 2. When La/Lb=1, the vertex spacings La and Lb are equal such that the spacing between the vertices is uniform. According to this simulation, when La/Lb is changed, the inrush flow is slightly reduced or improved compared to the equal vertex spacing in the artificial sea-mount M1 (first embodiment), but does not fall below the threshold. . Therefore, when the vertex distances La and Lb are not equal, the flow of water across the artificial sea-mount M3 becomes more complex, and the internal waves are changed due to the influence thereof. The inrush flow rate also changes and may exceed the inrush flow of the artificial seamount M1 (first embodiment). Especially when La/Lb=1.2 or La/Lb 0.83, and if one of La and Lb is 1.25r and the other is 1.5r, the inrush flow rate is the maximum amount, as can be seen from Fig. 6.

According to the artificial sea-mount mountain M3 of the second embodiment, since there are different vertex spacings between the two adjacent cones, unlike the first embodiment, the gap formed between the three cones does not have a bilaterally symmetric inverted triangle. It can be known that the shape of the gap different from the artificial sea-mount mountain M1 of the first embodiment changes the vertical mixing effect, and sometimes achieves a larger effect than the artificial sea-mount mountain M1.

(Third embodiment)

In the first and second embodiments, the plurality of cones forming the artificial seamount have equal apex heights H and equal bottom radii r. In a third embodiment, the plurality of cones can have different apex heights. In Fig. 7A, the artificial sea-mount mountain M4a of the third embodiment is formed by arranging three cones C1, C2 and C3. The apex height H1 of the two cones C1 and C3 at both ends is higher than the apex height H2 of a cone C2 at the center. In Fig. 7B, the artificial sea-mount mountain M4b of the third embodiment is formed by arranging four cones C1, C2, C3 and C4. The apex height H3 of the two cones C1 and C4 at both ends is lower than the apex height H4 of the two cones C2 and C3 at the center. It is to be noted that since the cones have equal bottom radii r, the slope of the conical surface between the cones varies with different apex heights.

As a variant of the first embodiment, the plurality of cones may have different bottom radii r. When this is applied to the artificial sea-mount mountain M1 shown in FIG. 1A, among the three cones C1, C2 and C3, the bottom radius ra of the two cones C1 and C3 at both ends is set to be larger than the middle. The radius rb of the bottom of a cone C2, but not shown in the figure. It is to be noted that when adjacent cones have different bottom radii, the average radius ra of the different bottom radii of the adjacent cones is used. Let r1 and r2 be the radii of two adjacent cones, and the average radius ra = (r1 + r2)/2. In this case, the vertex distance L is preferably in the range of from 0.75 to 2 ra.

Thus, the cones having some or all of the different apex spacing L, apex height H, and bottom radius r can be constructed by controlling the difference in the shape of the block to be placed from the sea level, depending on the material. Type, number of blocks, size and positioning angle of the work vessel to be put on work, placement position, release time limited by cable or the like, use of biodegradable rope or the like to loosely bind The extent of the block, as well as the velocity and direction of the tidal current, the wind direction and wind speed, and the wave condition at the time of launch.

A group of a plurality of blocks (hereinafter referred to as a block group) is loaded in a plurality of stages on the work ship, and the block group of the upper stage and the block group of the lower stage are a time difference Delivery. This prevents the inevitable collision between the block group and the work boat body. This can reduce the number of voyages that the work boat uses to carry out the work, and can improve the efficiency and economic benefits of reducing CO ₂ emissions during navigation.

( Fourth embodiment )

Next, the fourth embodiment will be explained with reference to Fig. 8. In the fourth embodiment, a mountain group is formed by linearly arranging two or more artificial sea-mount mountains according to the first to third embodiments. In Fig. 8, one of the artificial seamount M2a (first cone array) and an artificial seabed each having the same shape as the artificial sea-mount M2 formed by the four cones C1 to C4 shown in Fig. 4A. The mountains M2b (second cone array) are linearly arranged to form a group of mountains. In the artificial sea-mount mountains M2a and M2b, the vertex spacing L of the cones is set to be 0.75r to 2r.

Figure 9 is a diagram showing the relationship between the inrush flow rate and the vertex spacing Lm between the cones disposed adjacent to the ends of the two-linear configuration artificial sea-mounts M2a and M2b (hereinafter, the adjacent vertex spacing Lm) Express). Figure 9 shows three examples in which the vertex spacing is 1r, 1.25r and 2r. From this simulation, it can be seen that when the vertex spacing between the cones of the artificial sea-mount mountains M2a and M2b is 2r, and the adjacent mountain vertex spacing Lm between the artificial sea-mount mountains M2a and M2b is greater than 4.5r, The surge flow falls below this threshold. Otherwise, the inrush flow is greater than the threshold. Therefore, the adjacent mountain vertex spacing Lm is preferably less than 4.5r. That is, if the adjacent mountain vertex spacing Lm exceeds 4.5r, it is less effective to form a mountain group. In addition, if the adjacent mountain vertex spacing Lm is less than 2r, the mountain group will be equivalent to the artificial sea-mount mountain formed by continuously arranging several cones according to the first to third embodiments, thereby becoming Not effective.

In the fourth embodiment, each of the artificial sea-mount mountains M2a and M2b can produce effective vertical mixing as in the first embodiment. In addition, an inverted triangular gap is formed between the two artificial sea-mount mountains M2a and M2b, and a plurality of inclined faces are formed. Therefore, changes in the flow or vortex caused by the artificial seamounts M2a and M2b can effectively act in the area of the artificial seamount group. It is known that vertical mixing occurs in a wide area along the direction of the artificial seamounts contained in the group of artificial seamounts, and this makes it possible to produce a superior multiplier effect than the single artificial seamounts M2a and M2b.

Also in the fourth embodiment, an artificial sea-mountain group may be constructed by linearly configuring a plurality of artificial sea-mount mountains each having a cone having a different vertex spacing L or a vertex height H as in the third embodiment.

In the first to fourth embodiments, for example, when constructing an artificial sea-bottom mountain having the largest flow rate, the depth, water flow state, density distribution, nutrient concentration distribution, and the like in the target seafloor region are used as inputs. data. In addition, the number of cones, the apex of the cone, the height of the apex, the radius of the bottom, the inclination, the number of seamounts included in a group of artificial seamounts, the spacing between seamounts, and the like are also used. parameter. By performing an analytical operation, the vertical mixing amount per unit volume of the artificial sea-mount mountain range is maximized on a horizontal cross section close to the compensation depth, and the total vertical mixing amount close to the compensation depth is maximized, and the manama with the greatest effect can be achieved. Seamounts. In this case, the total vertical mixing amount can be obtained by integrating the vertical mixing amount of the water depth region on both sides of the compensation depth. In addition, the optimal shape and proportion of the artificial sea-mount mountain range can be calculated by considering the reciprocating flow of the ebb and the high tide.

In the above simulation, the inrush flow is defined as the amount of nutrient salt that passes through a horizontal cross section at various depths throughout the flow calculation region. Otherwise, the influx of water for a long period of time can be obtained by averaging the amount of nutrient salt that moves vertically through the compensated depth in all vertical cross sections downstream of the artificial seamount.

In the first to fourth embodiments, the artificial sea-mount mountain range is constructed by directly stacking blocks on the seabed. However, if the seabed is soft, it may be difficult to construct an artificial seamount as expected because the stacked blocks are buried. Preferably, in this case, the prior work constructed in the artificial sea-mount mountain range firstly lays components, such as blocks, evenly on the seabed to form a foundation, and then constructs the artificial sea-mount mountain range on the foundation.

The invention can be applied to artificial seamounts constructed on the seabed, in particular independently of the method of construction.

As described above, according to the present invention, it is possible to provide an artificial sea-mount mountain that can cause effective vertical mixing in the vicinity of the compensation depth even in a deep sea area of intense density stratification.

M1, M2, M3, M4a, M4b, M2a, M2b. . . Artificial seamount

C1, C2, C3, C4. . . Cone

1A and 1B are perspective and front views of an artificial sea-mount mountain range according to a first embodiment of the present invention;

Figure 2 is a graph showing the relationship between the cone of the artificial sea-mount mountain range and the inrush flow according to the first embodiment;

Figure 3 is a graph showing the relationship between the vertex spacing and the inrush flow between the cones of the artificial sea-mount mountain range according to the first embodiment;

Figure 4 is a perspective view of an artificial sea-mount mountain range according to a modification of the first embodiment;

5A and 5B are perspective and front views of an artificial sea-mount mountain range in accordance with a second embodiment of the present invention;

Figure 6 is a graph showing the relationship between the vertex spacing and the inrush flow of the artificial sea-mount mountain range according to the second embodiment;

7A and 7B are perspective views of an artificial sea-mount mountain range according to a modification of the third embodiment of the present invention;

Figure 8 is a front elevational view of an artificial sea-mount mountain range in accordance with a fourth embodiment of the present invention;

Fig. 9 is a graph showing the relationship between the distance between adjacent artificial sea-mount mountains and the inrush flow according to the fourth embodiment.

M1. . . Artificial seamount

C1, C2, C3. . . Cone

Claims (4)

An artificial sea-mount mountain range, which is constructed by stacking a plurality of blocks on a seabed, using tidal currents, ocean currents and internal waves in the seas stacked by the plurality of blocks to vertically vertically in the surrounding sea area Mixed seawater characterized by comprising: a first array of cones comprising at least three cones linearly arranged on the seabed, each of the at least three cones being comprised by the plurality of blocks Forming, wherein the apex spacing between the cones adjacent to each other in the first array of cones is set to be 0.75 to 2 times the radius of the bottom of each of the cones. The seamount of claim 1, wherein the at least three cones have different vertex spacings in the first array of cones. The seamount mountain of claim 1, further comprising a second cone array formed by the plurality of blocks and comprising at least three cones linearly arranged on the seabed, wherein the first The array of cones and the array of second cones are arranged linearly. The seamount mountain of claim 3, wherein a vertex spacing between the cones disposed at adjacent ends of the first cone array and the second cone array is set to each of the cones The bottom radius is 2 to 4.5 times.