JP2015160467A - underwater damper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a depth change in an underwater acoustic sensor even in a rapid tidal current state.SOLUTION: An underwater damper 13 is used under an environment having a tidal current, and is constituted of a freely foldable sheet-like body 20, and the body 20 is divided into at least two sections, and the first section 28 is provided with a relief hole 21 for opening a part of the body 20, and the second section 29 is positioned around the first section 28, and the body 20 is folded up so that the second section 29 covers the relief hole 21 of the first section 28, and a folding-up state 27 is formed, and the folding-up state changes in response to a speed of the tidal current, and is put in a first arrangement mode, and when the speed of the tidal current is less than a pre-assumption state, the second section 29 intercepts the tidal current of flowing in the relief hole 21 of the first section 28, and is put in a second arrangement mode, and when the speed is the pre-assumption speed or more, the tidal current is released from the relief hole 21 of the first section 28.

Description

  The present invention relates to an underwater damper, and more particularly, to an underwater damper that reduces the depth displacement of a foldable sheet-like main body and prevents the underwater acoustic sensor from lifting.

  Conventionally, there has been a drifting buoy system including a float, an underwater damper, and an underwater acoustic sensor (see, for example, Patent Document 1).

  An example of the drifting buoy system 1 will be described with reference to FIGS. FIG. 11 is a diagram illustrating an example of a schematic configuration of the drifting buoy system 1 in a static environment in the related art. FIG. 12 is a diagram illustrating an example of a schematic configuration of the drifting buoy system 1 in the environment of a slow tidal state in the related art. FIG. 13 is a diagram illustrating an example of a schematic configuration of the drifting buoy system 1 in the environment of a fast tidal state in the related art.

  As shown in FIG. 11, the drifting buoy system 1 has a cable 17 connected between the float 11 and the underwater acoustic sensor 15, and an underwater damper 13 provided in the cable 17 shows a relative tidal difference from the ocean current. By reducing the noise, noise generated around the underwater acoustic sensor 15 is prevented.

  The underwater damper 13 receives a lateral force such as a tidal current, and functions as a sea anchor that tries to keep the underwater acoustic sensor 15 at a set depth. For example, as shown in FIG. 12, the drifting buoy system 1 receives a small drag due to the horizontal flow of the tidal current when it is provided in a slow tidal environment. As a result, the underwater damper 13 moves by the angle θ formed by the float 11 and the vertical direction, for example, by receiving lift.

  Thereby, although the displacement of the depth of the underwater acoustic sensor 15 occurs, since the displacement is slight, the underwater acoustic sensor 15 is kept at the set depth.

  On the other hand, for example, as shown in FIG. 13, when the drifting buoy system 1 is provided in an environment of a fast tidal current state, it receives a large drag due to the horizontal flow of the tidal current. As a result, when the underwater damper 13 receives a large lift, for example, the displacement of the angle θ between the float 11 and the vertical direction increases, and the movement range increases accordingly.

  Therefore, since the displacement of the depth of the underwater acoustic sensor 14 is large, the underwater acoustic sensor 15 does not stay at the set depth. Specifically, in the environment of a tidal current having a fast current such as the Kuroshio existing around Japan, the underwater damper 13 is lifted as shown in FIG. 13, so that the underwater acoustic sensor 15 stays at a necessary setting depth. Absent.

JP 11-142498 A (paragraph [0003])

  In other words, as described above, when the conventional drift buoy system 1 is provided in a fast tidal environment, the displacement of the depth of the underwater acoustic sensor becomes large. For this reason, in the conventional drift buoy system 1, the underwater acoustic sensor 15 may be lifted depending on the tidal current. Therefore, there is a possibility that the drifting buoy system 1 of the prior art cannot keep the underwater acoustic sensor 15 at the originally required installation depth.

  In other words, it has been desired to reduce the displacement of the depth of the underwater acoustic sensor even in a fast tidal state.

  The underwater damper of the present invention is an underwater damper that is used in a tidal environment and is composed of a foldable sheet-like main body. The main body is divided into at least two sections, and the two sections Of these, the first section is provided with a hole in which a part of the main body is opened. Of the two sections, the second section is located around the first section. The hole of the first section is folded so that the second section covers the hole, and a folded state is formed. The folded state changes according to the speed of the tidal current, and the first arrangement As an aspect, if the speed of the tidal current is less than a speed assumed in advance, the second section blocks the tidal current flowing through the hole of the first section, Above the speed assumed in advance, the first section It is intended to release the power flow from.

  In the underwater damper of the present invention, the main body maintains the first arrangement mode when the tidal current speed is less than the previously assumed speed, and the tidal current speed is Above the assumed speed, the second arrangement mode is maintained.

  Moreover, the underwater damper of the present invention includes a foldable restraining member, and the restraining member is configured such that, of the second compartments, the main body covers the holes of the first compartment. When the speed of the tidal current is less than the previously assumed speed, the main body holds the first arrangement mode, and the speed of the tidal current is not less than the previously assumed speed. The main body holds the second arrangement mode.

  Moreover, in the underwater damper of the present invention, a plurality of the main bodies are provided along the vertical direction, and the total opening area of the holes is increased as the water depth becomes shallower.

  Further, in the underwater damper according to the present invention, the main body has a longitudinal shape and is provided along the vertical direction so that the total opening area of the hole is increased as the water depth becomes shallower. .

  In the underwater damper of the present invention, the main body is provided with a plurality of the holes, and the number of the holes is increased as the depth of the water becomes shallower.

  Further, in the underwater damper of the present invention, the main body has a shape of the hole different along a vertical direction, and the hole has a larger area as the water depth becomes shallower. is there.

  In the underwater damper of the present invention, the underwater damper is provided between the float and the underwater acoustic sensor via a cable.

  The present invention provides a foldable sheet-like body by changing the folding state formed between the shape of the compartment provided with the hole and the shape of the compartment provided with no hole according to the speed of the tidal current. The displacement of the depth of the underwater acoustic sensor can be reduced, and the underwater acoustic sensor can be prevented from lifting.

It is a figure which shows an example of schematic structure of the drifting buoy system 1 of Embodiment 1 of this invention. It is a figure which shows an example of a structure of the underwater damper 13 of Embodiment 1 of this invention. It is a figure which shows an example of the underwater damper 13 in the environment of the stationary state of Embodiment 1 of this invention. It is a figure which shows an example of the underwater damper 13 in the environment of the slow tidal current state of Embodiment 1 of this invention. It is a figure which shows an example of the underwater damper 13 in the environment of the fast tidal current state of Embodiment 1 of this invention. It is a figure which shows an example of a structure of the underwater damper 13 of Embodiment 2 of this invention. It is a figure which shows an example of a structure of the underwater damper 13 of Embodiment 3 of this invention. It is a figure which shows an example of a structure of the underwater damper 13 of Embodiment 4 of this invention. It is a figure which shows an example of a structure of the underwater damper 13 of Embodiment 5 of this invention. It is a figure which shows an example of a structure of the underwater damper 13 of Embodiment 6 of this invention. It is a figure which shows an example of schematic structure of the drifting buoy system 1 in the environment of a stationary state in a prior art. It is a figure which shows an example of schematic structure of the drifting buoy system 1 in the environment of a slow tidal current state in a prior art. It is a figure which shows an example of schematic structure of the drifting buoy system 1 in the environment of a quick tidal current state in a prior art.

  Hereinafter, Embodiments 1 to 6 of the present invention will be described in detail with reference to the drawings.

Embodiment 1 FIG.
<Overview>
As will be described later, the underwater damper 13 has a folded state 27 formed by the shape of the compartment provided with the escape hole 21 and the shape of the compartment provided with no escape hole 21 according to the speed of the tidal current. By changing, the displacement of the depth of the foldable sheet-like main body 20 is reduced, and the underwater acoustic sensor 15 is prevented from being lifted.

<Description of configuration>
First, an overall configuration example will be described with reference to FIG. FIG. 1 is a diagram showing an example of a schematic configuration of a drifting buoy system 1 according to Embodiment 1 of the present invention. As shown in FIG. 1, the drifting buoy system 1 includes, for example, a float 11, an underwater damper 13_1 to an underwater damper 13_N, and an underwater acoustic sensor 15. In the drifting buoy system 1, for example, after being dropped from an aircraft or the like into the sea 3, the underwater dampers 13 </ b> _ <b> 1 to 13 </ b> _N and the underwater acoustic sensor 15 are deployed in the sea, the float 11 floats on the sea surface, and the underwater acoustic sensor 15 Is in a state of sensing sound at a set depth.

  The timing at which the underwater acoustic sensor 15 starts sensing is not particularly limited. For example, when the drifting buoy system 1 starts to contact the sea 3, sensing of the underwater acoustic sensor 15 may be started.

  The float 11 is balanced with the underwater damper 13_1 to the underwater damper 13_N and the underwater acoustic sensor 15, and supplies various signals supplied from the underwater acoustic sensor 15 to the outside.

  The underwater damper 13_1 to the underwater damper 13_N have a function of an anchor effect that stabilizes the posture of the underwater acoustic sensor 15, and the underwater acoustic sensor 15 is prevented from flowing by the tidal current. It is intended to prevent the lifting.

  The underwater acoustic sensor 15 acquires acoustic data at a set depth by receiving sound at a set depth, and supplies the acoustic data to the float 11 via the cable 17.

  Note that the underwater dampers 13_1 to the underwater dampers 13_N are referred to as the underwater dampers 13 unless particularly distinguished from each other. In addition, although an example in which a plurality of underwater dampers 13 are provided has been described in FIG. 1, the present invention is not particularly limited thereto. For example, the case where only one underwater damper 13 is provided may be used.

  Next, details of the underwater damper 13 will be described with reference to FIG. FIG. 2 is a diagram illustrating an example of the configuration of the underwater damper 13 according to the first embodiment of the present invention. As shown in FIG. 2, each of the first state 31, the second state 32, and the third state 33 will be described in order. First, the first state 31 will be described. The first state 31 is a state in which a main body 20 described later is deployed.

  The underwater damper 13 has a relief hole 21 formed in the main body 20. The underwater damper 13 is provided with a cable 17 on the main body 20. The cable 17 is disposed in the main body 20 so as to bypass the periphery of the escape hole 21. The cable 17 is disposed on the main body 20 by being fixed to the main body 20 with, for example, an adhesive tape 23. Such an underwater damper 13 is folded before being dropped into the sea 3. Further, the shape of the escape hole 21 is, for example, a circle, but is not particularly limited thereto.

  In other words, the underwater damper 13 is used in an environment having a certain depth and a certain amount of tidal current, and is configured by a foldable sheet-like main body 20. The main body 20 is formed of a fibrous material that does not have directionality in strength and elongation, and can be easily changed in shape, such as cloth.

  The main body 20 is divided into at least two sections. Of the two compartments, the first compartment 28 has a relief hole 21 formed therein, and a part of the main body 20 is opened. The escape hole 21 is an opening through which the tide is released. On the other hand, of the two sections, the second section 29 is located around the first section 28 and blocks the tidal current.

  Next, the second state 32 will be described. The first state 31 is a state where the main body 20 is unfolded, while the second state 32 is a state where a part of the main body 20 is folded. The main body 20 is folded with the portion including the escape hole 21 as a valley side.

  In other words, the underwater damper 13 is one in which a part of the second section 29 including the first section 28 is folded.

  Next, the third state 33 will be described. The third state 33 is a folded state 27 in which a part of the main body 20 is folded so that the escape hole 21 of the first section 28 is covered by the second section 29.

  Specifically, a part of the folded main body 20 is fastened by the restraining member 25_1 and the restraining member 25_2, and the escape hole 21 is positioned on the valley side of the folded main body 20, whereby the folded state 27 is formed. ing. Each of the suppression member 25_1 and the suppression member 25_2 is formed of, for example, the same material as that of the main body 20, and is configured as a foldable sheet-like member.

  In other words, in the main body 20, a folded state 27 is formed by a part of the second section 29 and the first section 28, and the folded state 27 changes according to the speed of tidal current, as will be described later. Is. Note that the suppression member 25_1 and the suppression member 25_2 will be referred to as the suppression member 25 when not particularly distinguished from each other.

  In addition, the change degree of the folding state 27 formed by the 1st division 28 and the 2nd division 29 can be adjusted by changing the length of the suppression member 25. FIG. For example, if the length of the restraining member 25 is increased, the degree of development of a part of the folded main body 20 increases, so that more tidal current can be released from the escape hole 21. On the other hand, if the length of the restraining member 25 is shortened, the degree of development of a part of the folded main body 20 is reduced, so that the tidal current can be released from the escape hole 21 to a small extent. Thus, since the flow rate of the tidal current that passes through the escape hole 21 can be adjusted according to the length of the suppression member 25, the underwater damper 13 adjusts the overall drag according to the length of the suppression member 25. Can do.

  Further, if the material of the restraining member 25 is formed of a highly stretchable material, the folded state 27 formed by the first compartment 28 and the second compartment 29 can be used even if the length of the restraining member 25 is not used. The degree of change can be adjusted.

  Even if the suppressing member 25 is not used, the folded state 27 may be maintained by making the material of the main body 20 highly stretchable and fixing a part of the folded main body 20 with a fixing means. Here, the fixing means is not particularly limited. For example, a part of the folded main body 20 may be fixed with an adhesive or the like, may be fixed by fusing, or may be fixed by sewing.

<Description of operation>
Next, the operation of the underwater damper 13, which is a main part of the present invention, will be described with reference to FIGS. FIG. 3 is a diagram illustrating an example of the underwater damper 13 in the stationary environment according to the first embodiment of the present invention. FIG. 4 is a diagram illustrating an example of the underwater damper 13 in the environment of the slow tidal current state according to the first embodiment of the present invention. FIG. 5 is a diagram illustrating an example of the underwater damper 13 in the fast tidal current environment according to the first embodiment of the present invention.

  In the case of FIG. 3, the underwater damper 13 is kept in a stationary state because it is balanced by the retaining force of the float 11 on the sea surface and the underwater weight of the underwater acoustic sensor 15. The retaining force of the float 11 on the sea surface is generated by, for example, the buoyancy of the float 11 and the tidal power of the sea surface.

  In the case of FIG. 4, the underwater damper 13 is in an environment receiving a slow tidal current. Specifically, the underwater damper 13 receives a weak horizontal flow in a portion of the tidal current where the drag is generated. In this state, the shape of the folding state 27 of the underwater damper 13 including the escape hole 21 and the main body 20 changes according to the speed of the tidal current.

  Specifically, the underwater damper 13 has a shape of a folded state 27 formed by folding a part of the main body 20 including the escape hole 21 when the speed of the tidal current is less than a speed assumed in advance. The 1st arrangement | positioning aspect to maintain is hold | maintained. Therefore, since the main body 20 is configured to block the tidal current by the second section 29 blocking the escape hole 21 of the first section 28, displacement of the depth due to the slow tidal current is suppressed. That is, the suppressing member 25 causes the main body 20 to hold the first arrangement mode under a slow tidal current.

  In the case of FIG. 5, the underwater damper 13 is in an environment receiving a fast tidal current. Specifically, the underwater damper 13 receives a strong horizontal flow in the tidal current at a portion where the drag is generated. In this state, the shape of the folding state 27 of the underwater damper 13 including the escape hole 21 and the main body 20 changes according to the speed of the tidal current.

  Specifically, the underwater damper 13 is a part of the folded main body 20 when the speed of the tidal current is equal to or higher than a speed assumed in advance, and is a part of the folded main body 20. A large gap is generated at the folded point with the valley side. Next, the escape hole 21 expands within a range where the main body 20 is suppressed by the suppression member 25. As a result, the underwater damper 13 maintains the second arrangement mode in which the tidal current is released from the escape hole 21. Therefore, since the main body 20 is configured to release the tidal current from the escape hole 21 of the first section 28, displacement of the depth due to the fast tidal current is suppressed. That is, the suppressing member 25 causes the main body 20 to hold the second arrangement mode even under a fast tidal current.

  In other words, even under a fast tidal current, the underwater damper 13 has a configuration in which a part of the tidal current is removed from the escape hole 21. Therefore, drag beyond the assumed tidal current is released. Therefore, even under a fast tidal current, the overall drag received by the underwater damper 13 is the same as that under a slow tidal current.

<Description of operating principle>
Next, as an operation principle of the present invention, the drag will be described using mathematical expressions. The drag of the underwater damper 13 is obtained from the general formula of the drag expressed by the following formula (1).

  Here, D is drag, ρ is density, Cd is drag coefficient, S is area, and V is velocity. Among these, since ρ is density, it does not change under the condition of underwater. Therefore, although the drag D depends on the drag coefficient Cd, the area S, and the speed V, the speed V is a tidal current speed, and thus is not a parameter that can be controlled by the underwater damper 13. Therefore, the drag D is reduced by adjusting the area S and the drag coefficient Cd.

  That is, even under a fast tidal current, the underwater acoustic sensor 15 is prevented from being lifted by the lift of the underwater damper 13 by adjusting the area S and the drag coefficient Cd. Here, if the following equation (2) is satisfied, the underwater acoustic sensor 15 is lifted.

  Therefore, the state shown in the following formula (3) must be obtained.

  Here, the lift of the underwater damper 13 is generated by receiving the tidal velocity V, but can be reduced by the area S of the underwater damper 13 and the drag coefficient Cd. On the other hand, the underwater weight of the underwater acoustic sensor 15 depends on the structure of the underwater acoustic sensor 15.

  The speed V assumed by the tidal current varies according to the set depth and the environment in which the underwater damper 13 is provided. Therefore, the area S and the drag coefficient Cd of the underwater damper 13 may be adjusted according to the target tidal velocity V and the underwater weight of the underwater acoustic sensor 15.

  Specifically, the lift of the underwater damper 13 is generated by the drag D of the underwater damper 13. Therefore, when the tidal velocity V is high, for example, the overall drag D applied to the underwater damper 13 may be reduced by adopting a configuration in which the tidal current is removed from the escape hole 21.

  Therefore, the underwater damper 13 exhibits a function as a sea anchor when receiving a slow tidal current, that is, a weak drag D. On the other hand, when the underwater damper 13 receives a fast tidal current, that is, a strong drag D, the underwater damper 13 functions as a sea anchor while escaping the tidal current and reducing the drag D.

  In particular, when the underwater damper 13 receives a fast tidal current, the drag D generated from the tidal current is released from the hole 21 due to a change in shape. In this way, the underwater damper 13 uses the phenomenon that the shape of the folded state 27 changes when seawater passes through the gap of the folded state 27 formed in the main body 20 by receiving the force of the tidal current. Drag D is adjusted.

  In other words, the underwater damper 13 is a first section 28 in which the escape hole 21 is formed and a part of the main body 20 that forms the periphery of the escape hole 21 according to the speed of the tidal current. The shape of the folded state 27 formed by the section 29 changes. Therefore, during a fast tidal current, the tidal current is released from the escape hole 21 and the drag D is reduced. Therefore, the underwater damper 13 reduces the lift D and reduces the depth displacement of the underwater acoustic sensor 15 in order to reduce the drag D received as a whole.

<Description of effects>
From the above description, even when the underwater damper 13 is subjected to a tidal current of a speed that is assumed in advance, the relief hole 21 is provided, so that the drag D is reduced, thereby suppressing the generation of lift. As a whole, the force received from the tidal current is reduced.

  Thereby, since the underwater damper 13 can suppress the displacement of the depth even under a fast tidal current, the displacement of the depth of the underwater acoustic sensor 15 can be suppressed. As a result, the underwater damper 13 can be maintained at a set depth assuming the underwater acoustic sensor 15.

  As described above, in the first embodiment, the underwater damper 13 is composed of a foldable sheet-like main body 20 that is used in a tidal environment, and the main body 20 is divided into at least two sections. Of the two compartments, the first compartment 28 is provided with a relief hole 21 in which a part of the main body 20 is opened. Of the two compartments, the second compartment 29 is formed around the first compartment 28. The main body 20 is folded so that the second section 29 covers the escape hole 21 of the first section 28 to form a folded state 27. Depending on the speed of the tidal current, the folded state 27 is If the speed of the tidal current is less than the speed assumed in advance, the second section 29 blocks the tidal current flowing through the escape hole 21 of the first section 28 as the first disposition mode. As an arrangement mode of In-water damper 13 to release the forward flow from the relief holes 21 of the first compartment 28 is formed.

  Further, in the first embodiment, the main body 20 maintains the first arrangement mode when the tidal current speed is less than the presumed speed, and the tidal current speed is the presumed speed. Above this, the second arrangement mode may be maintained.

  Further, in the first embodiment, a foldable restraining member 25 is provided, and the restraining member 25 has the main body 20 out of the second compartment 29 with the escape hole 21 of the first compartment 28 in the second compartment 29. If the speed of the tidal current is less than the speed assumed in advance, the main body 20 holds the first arrangement mode, and at a speed higher than the speed assumed in advance, The main body 20 may hold the second arrangement mode.

  In the first embodiment, an underwater damper 13 may be provided via the cable 17 between the float 11 and the underwater acoustic sensor 15.

  In other words, the underwater damper 13 is folded according to the folding state 27 formed by the shape of the compartment provided with the hole and the shape of the compartment provided with no hole according to the speed of the tidal current. The displacement of the depth of the flexible sheet-like main body 20 can be reduced, and the underwater acoustic sensor 15 can be prevented from being lifted. Thereby, since the sensing result of the underwater acoustic sensor 15 becomes sound of a depth assumed in advance, the underwater damper 13 can improve the accuracy of sensing of the underwater acoustic sensor 15.

Embodiment 2. FIG.
<Overview>
FIG. 6 is a diagram illustrating an example of the configuration of the underwater damper 13 according to the second embodiment of the present invention. As shown in FIG. 6, in the second embodiment, it is assumed that the main body 20 of the underwater damper 13 has a longitudinal shape and is provided along the vertical direction.

<Description of configuration>
Specifically, the number of escape holes 21 may be increased as the water depth becomes shallower, or the area of the escape hole 21 may be increased as the water depth becomes shallower. That is, it is only necessary that the total opening area of the escape hole 21 is increased as the water depth becomes shallower.

<Description of effects>
From the above description, even when the underwater damper 13 is subjected to a tidal current of a speed that is assumed in advance, the relief hole 21 is provided according to the water depth, so that the drag according to the degree of the drag D is provided. Since D is reduced, the generation of lift can be reliably suppressed at any depth, and the force received from the tidal current as a whole can be reduced.

  As described above, in the second embodiment, a plurality of the main bodies 20 may be provided along the vertical direction, and the total opening area of the escape holes 21 may be increased as the water depth becomes shallower.

  In the second embodiment, the main body 20 may be provided with a plurality of escape holes 21, and the number of the escape holes 21 may be increased as the depth of the water becomes shallower.

  Further, in the second embodiment, the main body 20 has a different shape of the escape hole 21 along the vertical direction, and the area of the escape hole 21 is increased as the water depth becomes shallower. Also good.

  In other words, since the underwater damper 13 can reliably suppress the displacement of the depth even under a fast tidal current, the displacement of the depth of the underwater acoustic sensor 15 can be reliably suppressed. As a result, the underwater damper 13 can reliably maintain the underwater acoustic sensor 15 at an assumed set depth. Thereby, since the sensing result of the underwater acoustic sensor 15 becomes sound of a depth assumed in advance, the underwater damper 13 can improve the accuracy of sensing of the underwater acoustic sensor 15.

Embodiment 3 FIG.
<Overview>
FIG. 7 is a diagram illustrating an example of the configuration of the underwater damper 13 according to the third embodiment of the present invention. As shown in FIG. 7, in the third embodiment, it is assumed that a plurality of main bodies 20 of the underwater damper 13 are provided along the vertical direction.

<Description of configuration>
Specifically, the number of escape holes 21 may be increased as the water depth becomes shallower, or the area of the escape hole 21 may be increased as the water depth becomes shallower. That is, it is only necessary that the total opening area of the escape hole 21 is increased as the water depth becomes shallower.

<Description of effects>
From the above description, even when the underwater damper 13 is subjected to a tidal current of a speed that is assumed in advance, the relief hole 21 is provided according to the water depth, so that the drag according to the degree of the drag D is provided. Since D is reduced, the generation of lift can be reliably suppressed at any depth, and the force received from the tidal current as a whole can be reduced.

  As described above, in the third embodiment, the main body 20 has a longitudinal shape, is provided along the vertical direction, and the total opening area of the escape hole 21 is increased as the water depth becomes shallower. Good.

  In the third embodiment, the main body 20 may be provided with a plurality of escape holes 21, and the number of the escape holes 21 may be increased as the water depth becomes shallower.

  Further, in the third embodiment, the main body 20 has a different shape of the escape hole 21 along the vertical direction, and the area of the escape hole 21 is increased as the water depth becomes shallower. Also good.

  In other words, since the underwater damper 13 can reliably suppress the displacement of the depth even under a fast tidal current, the displacement of the depth of the underwater acoustic sensor 15 can be reliably suppressed. As a result, the underwater damper 13 can reliably maintain the underwater acoustic sensor 15 at an assumed set depth. Thereby, since the sensing result of the underwater acoustic sensor 15 becomes sound of a depth assumed in advance, the underwater damper 13 can improve the accuracy of sensing of the underwater acoustic sensor 15.

Embodiment 4 FIG.
<Overview>
FIG. 8 is a diagram illustrating an example of the configuration of the underwater damper 13 according to the fourth embodiment of the present invention. As shown in FIG. 8, in the fourth embodiment, a foldable sheet-like cylindrical member 41 is provided in a part of the main body 20 of the underwater damper 13, and a relief hole 21 is provided at the tip of the cylindrical member 41. Assumes that

<Description of configuration>
Specifically, under a fast tidal current, the tubular member 41 of the underwater damper 13 extends, and the tidal current escapes from the escape hole 21 provided at the tip of the tubular member 41.

<Description of effects>
As described above, the underwater damper 13 is provided with the relief hole 21 even when receiving a tidal current of a speed that is assumed in advance, so that the generation of lift is suppressed in order to reduce the drag D. As a whole, the force received from the tidal current is reduced.

  Thereby, since the underwater damper 13 can suppress the displacement of the depth even under a fast tidal current, the displacement of the depth of the underwater acoustic sensor 15 can be suppressed. As a result, the underwater damper 13 can be maintained at a set depth assuming the underwater acoustic sensor 15. Thereby, since the sensing result of the underwater acoustic sensor 15 becomes sound of a depth assumed in advance, the underwater damper 13 can improve the accuracy of sensing of the underwater acoustic sensor 15.

Embodiment 5 FIG.
<Overview>
FIG. 9 is a diagram illustrating an example of the configuration of the underwater damper 13 according to the fifth embodiment of the present invention. As shown in FIG. 9, it is assumed that a valve 43 is configured in the escape hole 21.

<Description of configuration>
The valve 43 is made of, for example, a flexible member, for example, a member formed from a material such as plastic, rubber, and carbon fiber. Therefore, the valve 43 is opened during a fast tide, and the tide flows from the escape hole 21.

<Description of effects>
According to the above description, the underwater damper 13 is provided with the relief hole 21 provided with the valve 43 even when receiving a tidal current of a speed that is assumed in advance, so that the drag force D is released, so that the lift force To reduce the force received from the tidal current as a whole.

  Thereby, since the underwater damper 13 can suppress the displacement of the depth even under a fast tidal current, the displacement of the depth of the underwater acoustic sensor 15 can be suppressed. As a result, the underwater damper 13 can be maintained at a set depth assuming the underwater acoustic sensor 15.

Embodiment 6 FIG.
<Overview>
FIG. 10 is a diagram illustrating an example of the configuration of the underwater damper 13 according to the sixth embodiment of the present invention. As shown in FIG. 10, for example, it is assumed that escape holes 51_1 to 51_9 are provided in the main body 20.

<Description of configuration>
As the function similar to the escape hole 21, the escape hole 51 </ b> _ <b> 1 to the escape hole 51 </ b> _ <b> 9 are formed in the main body 20. Here, when the relief holes 51_1 to 51_9 are not particularly distinguished, they are referred to as relief holes 51.

  In the example of FIG. 10, for example, an example in which nine escape holes 51 are provided is described. However, the example is not particularly limited thereto. Specifically, the number of the escape holes 51 may be increased as the water depth becomes shallower. The shape of the escape hole 51 is, for example, a circle, but is not particularly limited to this.

<Description of effects>
According to the above description, the underwater damper 13 is provided with the relief hole 51 provided with the valve 43 even when receiving a tidal current exceeding a speed assumed in advance. To reduce the force received from the tidal current as a whole.

  Thereby, since the underwater damper 13 can suppress the displacement of the depth even under a fast tidal current, the displacement of the depth of the underwater acoustic sensor 15 can be suppressed. As a result, the underwater damper 13 can be maintained at a set depth assuming the underwater acoustic sensor 15. Thereby, since the sensing result of the underwater acoustic sensor 15 becomes sound of a depth assumed in advance, the underwater damper 13 can improve the accuracy of sensing of the underwater acoustic sensor 15.

  1 Drifting buoy system, 3 sea, 11 float, 13, 13_1 to 13_N underwater damper, 15 underwater acoustic sensor, 17 cable, 20 body, 21, 51, 51_1 to 51_9 relief hole, 23 adhesive tape, 25, 25_1, 25_2 suppression Member, 27 folded state, 28 first compartment, 29 second compartment, 31 first state, 32 second state, 33 third state, 41 tubular member, 43 valve.

Claims (8)

It is an underwater damper that is used in a tidal environment and consists of a foldable sheet-shaped body,
Dividing the body into at least two compartments;
Of the two compartments, the first compartment is provided with a hole in which a part of the main body is opened,
Of the two compartments, the second compartment is located around the first compartment,
The body is
Folded so that the second compartment covers the hole of the first compartment, a folded state is formed,
According to the speed of the tidal current, the folding state changes,
As a first arrangement mode, when the speed of the tidal current is less than a speed assumed in advance, the second section blocks the tidal current flowing through the hole of the first section,
As a second arrangement mode, the underwater damper is characterized in that the tidal current is allowed to escape from the hole of the first section at a speed higher than the previously assumed speed. The body is
If the speed of the tidal current is less than the speed assumed in advance, the first arrangement mode is maintained,
2. The underwater damper according to claim 1, wherein the second arrangement mode is maintained when a speed of the tidal current is equal to or higher than the speed assumed in advance. With a foldable restraining member,
The suppression member is
Among the second sections, the main body is provided at a position folded so that the second section covers the hole of the first section,
The speed of the tidal current is
If the speed is less than the previously assumed speed, the main body is held in the first arrangement mode,
The underwater damper according to claim 2, wherein the second arrangement mode is held in the main body at a speed higher than the speed assumed in advance. The body is
A plurality are provided along the vertical direction.
4. The underwater damper according to claim 2, wherein a total opening area of the hole is formed larger as the depth of water becomes shallower. The body is
It has a longitudinal shape and is provided along the vertical direction.
4. The underwater damper according to claim 2, wherein a total opening area of the hole is formed larger as the depth of water becomes shallower. The body is
A plurality of the holes are provided;
The underwater damper according to claim 4 or 5, wherein the number of the holes is increased as the depth of water becomes shallower. The body is
The shape of the hole is different along the vertical direction,
6. The underwater damper according to claim 4, wherein an area of the hole is increased as the depth of water becomes shallower. The underwater damper according to any one of claims 1 to 7, wherein the underwater damper is provided via a cable between the float and the underwater acoustic sensor.

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