JPH04135120U - cable structure - Google Patents

Abstract

(57) [Summary] [Purpose] In cables used for towing, suspending, laying, etc. in fluid, many small depressions are arranged on the surface of the cable, and these depressions reduce the Karman vortex generated in the fluid. and reduce fluid resistance. [Structure] A large number of regularly arranged small depressions 3 are arranged on the surface of the cable to disturb the flow of fluid on the cable surface and prevent the flow from separating from the surface. In the fluid flow, the separation point of the flow is located relatively rearward, and the Karman vortex generated in the wake region becomes smaller.

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

This invention particularly relates to cables used for towing, suspending, laying, etc. in fluids. It is.

0002

[Conventional technology]

An example of conventional technology can be used for example when observing sound in a fluid. An example of such a cable will be explained below. The first conventional example shown in Fig. 2 is a commonly used towing cable (hereinafter simply cable). FIG. 2(a) is its external view, and FIG. 2(b) is FIG. 3 is a flow cross-sectional view showing the flow of fluid around the cable. When observing sound in a fluid, one end of the cable 1a is connected to the sound in the fluid. Hang an acoustic sensor (not shown) that observes the sound and store it by wrapping the other end around a drum, etc. Then, an acoustic sensor is placed into the fluid and observed. Crossing of cable 1a shown in the figure The surface is almost perfectly circular and has a smooth surface. shape like this A shaped cable is highly flexible and can be stored in a drum or the like relatively easily. Besides that It has features such as being able to lengthen the cable length. However, The fluid flow around the cable 1a is such that the flow separation point X1 is located relatively forward. Because the Karman vortex is large, the wake region Y1 of the cable 1a becomes large and the There is great resistance. Also, the direction of the flow tends to change rapidly.

0003 The second conventional cable 1b shown in FIG. 3 is different from the cable 1a shown in FIG. It is a cable with Fair 2. Figure 3(a) is an external view of the (b) is a flow sectional view showing the flow of fluid around the cable. The cross section of the cable 1b shown in the figure has a teardrop shape. Around cable 1b In the fluid flow, the flow separation point X2 is located relatively backward, and the Karman vortex is Because a small vortex forms along fair 2, the wake area Y2 of cable 1a becomes small. This reduces the resistance.

0004

[Problem that the idea aims to solve]

The advantage of the first conventional cable 1a is that it is highly flexible and can be stored in a drum, etc. It is relatively easy, and the cable length can be increased. however, The disadvantage of this is that the Karman vortex becomes large in the fluid, and the wake region of the cable Y1 becomes larger. This increases the resistance and makes it difficult for the cable to sink. Moreover, cable vibration is more likely to occur and noise is more likely to occur. this Therefore, it was difficult to make good observations when observing acoustics in fluids. In addition, in general, shaking Cable vibration can be reduced by installing a module in front of the acoustic sensor that dampens cable vibration. It is known that reducing noise reduces noise and improves acoustic performance.

[0005] The advantage of the second conventional cable 1b is that it reduces resistance due to fluid and reduces cable vibration. This means that it is possible to prevent the occurrence of motion. However, as a disadvantage, Fair 2 significantly reduces flexibility and makes storage difficult, making it difficult to store cables. If it is not possible to lengthen it, which limits operation, or if twisting occurs, It is inconvenient to deal with it (untwisting it). This resulted in low versatility.

[0006] Therefore, conventional methods have low resistance (in fluid), flexibility, and storage properties. It is extremely difficult to create a cable that has characteristics such as no damage to the cable. The realization of this has been long awaited.

[0007]

[Means to solve the problem]

In a cable used for towing, suspending, laying, etc. in a fluid, the cable is Karma that has regularly arranged depressions on the surface and is generated in the fluid by the depressions. It is characterized by reducing vortices and reducing fluid resistance.

[0008]

[Effect]

A large number of regularly arranged small depressions on the surface of the cable allow the cable to stay in the fluid. This reduces the Kalmar vortex generated in the wake area of the bull and reduces fluid resistance. Ma In addition, as with the conventional model, its feature is that it does not impair the flexibility and storage of the cable. Ru.

[0009]

【Example】

Hereinafter, the present invention will be explained with reference to illustrated embodiments. Figure 1 shows the cable structure according to the present invention, and Figure 1 (a) is its external view. , FIG. 1(b) is a flow cross-sectional view showing the flow of fluid around the cable. The cable structure (cable 1c) of the present invention is different from the conventional perfectly circular cable 1a (cable 1c). For cable 1b (second conventional example) in which fair 2 is placed on cable 1b (conventional example 1), this On the contrary, a large number of regularly arranged small depressions 3 are arranged on the surface of the cable 1a. It is characterized by By arranging a large number of these depressions 3, the area around the cable 1c is The fluid flow is as shown in FIG. 1(b). In other words, the flow separation point X3 is the cable 1c, and also in the wake area Y3 of cable 1c. The Karman vortex generated becomes smaller. This disturbs the fluid flow on the cable surface and causes This is because the flow does not separate from the surface as a result. As a result, it seems as if the second conventional The flow can be similar to the example, which reduces the resistance in the fluid. stop Since the fluid resistance is reduced, cable vibration can be suppressed. Also, The change in flow direction is a very gentle change compared to the first conventional example. Cable 1a of the first conventional example and cable 1c of the present invention with the same length under the same conditions A comparison of the sinking conditions when towing a ship is as shown in Figure 4. 4 is a ship , 5 is an acoustic sensor suspended from a cable, and α is the traveling direction of the ship 4. , β1 and β2 are the sinking angles of each acoustic sensor 5, and F and f are respectively This shows the resistance force of the fluid in the lateral direction. As shown, the cable 1c is Since the resistance is smaller than that of cable 1a (F>f), its sinking angle is deeper (β1< β2) It becomes. Therefore, when sinking cable 1c and cable 1a under the same conditions, The cable of the present invention (cable 1c) sinks deeper. As explained above, when observing acoustics in a fluid, it is necessary to Since the Kalmar vortex generated in the area is small, cable vibration is reduced and noise is reduced. This allows for better observation than before. Also, since the present invention (cable 1c) sinks deeper, set it to the intended depth. Easy to use, especially when observing acoustics in fluids or towing fishing nets. This makes it a suitable cable. Although the present invention has been explained based on a towing cable as an example, the present invention is , not limited to towing cables, but all cables used for towing, suspending, laying, etc. in fluids. This does not exclude these from the scope of claims for utility model registration of the present invention. stomach.

0010

[Effect of the idea]

As explained above in detail, according to the present invention, towing, suspension, laying, etc. By placing regularly arranged depressions on the surface of the cable used for The Kalmar vortex generated in the wake area of the engine can be reduced and the resistance can be reduced. . Therefore, it has the effect of suppressing cable vibration, and improves the acoustic performance of towed vehicles related to underwater acoustics. can be expected. In addition, since it does not impair the flexibility and storage of the cable, it can be easily stored in drums, etc. It is relatively easy to store, and the cable length can be increased. resistance due to fluid Since it is small, it can provide excellent effects such as making it easier for the cable to sink.

[Brief explanation of drawings]

FIG. 1 is an external view and a flow sectional view of a cable structure according to the present invention.

FIG. 2 is an external view and a flow sectional view of a cable structure according to a first conventional example.

FIG. 3 is an external view and a flow sectional view of a cable structure according to a second conventional example.

FIG. 4 is a comparison diagram of the degree of sinking of the cable structure according to the first conventional example and the present invention.

[Explanation of symbols]

1c cable 3 Hollow

Claims (1)

[Scope of utility model registration request] 1. A cable used for towing, suspending, laying, etc. in a fluid, wherein the cable has a large number of small depressions on its surface, and the depressions reduce Karman vortices generated in the fluid, Cable structure characterized by reduced fluid resistance.