JP6948780B2 - Underwater vehicle - Google Patents

Description

The present disclosure relates to an underwater vehicle.

For example, as a configuration capable of reducing the noise of a ship, Patent Document 1 discloses that a carbon fiber sheet with a molded circular protrusion is attached to an outer wall surface of the ship. According to this configuration, it is considered that energy loss can be significantly reduced and noise can be prevented by eliminating the fluid resistance by the small and regular circular protrusions.

Japanese Unexamined Patent Publication No. 2004-52547

Some underwater vehicles capable of navigating underwater have a protrusion that projects laterally from the main body of the underwater vehicle. Around this type of underwater vehicle, a vortex flow called a horseshoe-shaped vortex is generated by the interference between the protrusion protruding from the body of the underwater vehicle and the boundary layer of the flow that develops along the surface of the body. .. Since this vortex flow has a vertical vortex structure, the vortex is hard to be attenuated, and the flow velocity deviation and the secondary flow (in-plane swirling flow component orthogonal to the mainstream direction) due to the vortex remain to the downstream side of the flow.
When such a non-uniform flow field flows into a propulsion device (rotating body such as a propeller) located behind the protrusion, fluid noise is generated due to load fluctuation of the propulsion device and separation of the flow on the propulsion device surface. It may occur and cause a problem.
In view of the above circumstances, an object of at least one embodiment of the present invention is to provide an underwater vehicle in which the generation of fluid noise in the propeller is suppressed and the underwater vehicle is excellent in quietness.

(1) The underwater vehicle according to at least one embodiment of the present invention is
The main body extending in the axial direction and
A protruding portion protruding from the main body in a direction orthogonal to the axial direction,
A propulsion device located behind the protrusion in the axial direction,
With
The outer surface of the main body includes at least one uneven portion extending so as to surround the main body along the circumferential direction of the main body in front of the protruding portion in the axial direction of the main body.
The at least one uneven portion
A recess formed by a concave curve in a vertical cross-sectional view including the axial direction, and a recess
A convex portion formed by a convex curve in a vertical cross-sectional view including the axial direction and connected to the rear end of the concave portion in the axial direction.
Have,
The front end of the protrusion in the axial direction is located closer to the front end than the rear end of the main body in the axial direction .
When the height of the uneven portion in the radial direction of the main body is Ht and the distance between the uneven portion and the protruding portion in the axial direction is D, the distance ratio D / Ht is 1 or more and 10 It is as follows .

Since the horseshoe-shaped vortex is generated by the interference between the boundary layer of the flow and the protrusion, the generation of the horseshoe-shaped vortex can be suppressed by suppressing the development of the boundary layer. In this regard, according to the above configuration (1), the concavo-convex portion provided on the outer surface of the main body is composed of a concave curve and a convex curve in a vertical cross-sectional view, and the boundary layer flowing along the concavo-convex portion. The flow velocity can be increased and the thickness of the boundary layer can be reduced. As a result, the development of the boundary layer is suppressed and the formation of horseshoe-shaped vortices is suppressed, so that the formation of a non-uniform flow field is also suppressed. As a result, the underwater vehicle having the above configuration (1) is excellent in quietness because the generation of fluid noise in the propeller is suppressed.

(2) In some embodiments, in the above configuration (1),
The main body
With a tubular body and
A head protruding forward from the body in the axial direction,
Including
The at least one uneven portion includes an uneven portion located on the head.

According to the above configuration (2), since the uneven portion is formed on the head, the development of the boundary layer can be suppressed and the generation of the horseshoe-shaped vortex can be suppressed with a simple configuration.

(3) In some embodiments, in the above configuration (1) or (2),
The main body
With a tubular body and
A head protruding forward from the body in the axial direction,
Including
The at least one uneven portion includes an uneven portion located on the body portion.

According to the above configuration (3), since the uneven portion is formed on the body portion, the uneven portion can be arranged near the protruding portion. As a result, the thickness of the boundary layer can be reduced near the protrusion, so that the thickness of the boundary layer that interferes with the protrusion can be further reduced. As a result, the formation of horseshoe-shaped vortices can be further suppressed.

(4) In some embodiments, in any one of the above configurations (1) to (3),
The outer surface of the body further has a plurality of dimples and one or both of at least one circumferential groove in the axial direction in front of the protrusion.

According to the above configuration (4), the flow of fluid along the outer surface of the main body is in contact with the solid wall due to the generation of circulating flow (separation bubbles) in a plurality of dimples or in at least one circumferential groove. Instead, it comes into contact with the fluid (circulating flow). Therefore, the development of the boundary layer is suppressed by the plurality of dimples or at least one circumferential groove. As a result, the formation of horseshoe-shaped vortices can be further suppressed.

According to at least one embodiment of the present invention, the generation of fluid noise in the propulsion device is suppressed, and an underwater vehicle having excellent quietness is provided.

It is a side view which shows typically the underwater vehicle which concerns on one Embodiment of this invention. It is a schematic front view of the underwater vehicle of FIG. 1. It is an enlarged view of the region III in FIG. It is a figure for demonstrating the function of the concavo-convex part of an underwater vehicle, FIG. It is a figure for demonstrating the flow of the fluid around the uneven part of the middle navigation body. It is a side view which shows typically the underwater vehicle which concerns on another Embodiment of this invention. It is a schematic front view of the underwater vehicle of FIG. It is an enlarged view of the region VII in FIG. It is a side view which shows typically the underwater vehicle which concerns on another Embodiment of this invention. It is a side view which shows typically the underwater vehicle which concerns on another Embodiment of this invention.

Hereinafter, some embodiments of the present invention will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of the components described as embodiments or shown in the drawings are not intended to limit the scope of the present invention to this, but are merely explanatory examples. No.
For example, expressions that represent relative or absolute arrangements such as "in a certain direction", "along a certain direction", "parallel", "orthogonal", "center", "concentric" or "coaxial" are exact. Not only does it represent such an arrangement, but it also represents a state of relative displacement with tolerances or angles and distances to the extent that the same function can be obtained.
For example, expressions such as "same", "equal", and "homogeneous" that indicate that things are in the same state not only represent exactly the same state, but also have tolerances or differences to the extent that the same function can be obtained. It shall also represent the existing state.
For example, an expression representing a shape such as a quadrangular shape or a cylindrical shape not only represents a shape such as a quadrangular shape or a cylindrical shape in a geometrically strict sense, but also a concave protrusion or chamfering within a range in which the same effect can be obtained. The shape including the part and the like shall also be represented.
On the other hand, the expressions "equipped", "equipped", "equipped", "included", or "have" one component are not exclusive expressions that exclude the existence of other components.

FIG. 1 is a side view schematically showing an underwater vehicle 1 (1a) according to an embodiment of the present invention. FIG. 2 is a schematic front view of the underwater vehicle 1 (1a) of FIG. FIG. 3 is an enlarged view of region III in FIG. FIG. 4 is a diagram for explaining the function of the uneven portion of the underwater vehicle 1 (1a), and FIG. 4A is a graph schematically showing the relationship between the distance from the tip and the thickness of the boundary layer. (B) is a diagram for explaining the flow of fluid around the uneven portion of the underwater vehicle 1 (1a). FIG. 5 is a side view schematically showing an underwater vehicle 1 (1b) according to another embodiment of the present invention. FIG. 6 is a schematic front view of the underwater vehicle 1 (1b) of FIG. FIG. 7 is an enlarged view of the region VII in FIG. FIG. 8 is a side view schematically showing the underwater vehicle 1 (1c) according to another embodiment of the present invention. FIG. 9 is a side view schematically showing the underwater vehicle 1 (1d) according to another embodiment of the present invention.

As shown in FIGS. 1, 5, 8 and 9, the underwater navigation bodies 1a to 1d according to the embodiment of the present invention include a main body (hull) 3, at least one protrusion 5, and a propeller. It is equipped with a propeller 7 as a. The main body 3 extends in a direction along the axis Ax (axis direction). The protruding portion 5 protrudes from the main body 3 in a direction orthogonal to the axial direction. The propeller 7 is located behind the protrusion 5 in the axial direction.
The underwater vehicles 1a to 1d are, for example, submarines. In this case, the main body 3 has a shape such as a teardrop shape or a cigar shape, and the protruding portion 5 is a bridge or the like.
In the following description, the underwater vehicles 1a to 1d are also collectively referred to as the underwater vehicle 1.

As shown in FIGS. 1 to 3, 4 (b), and 5 to 9, the outer surface of the main body 3 of the underwater vehicle 1 has an uneven portion 9. The uneven portion 9 is located in front of the protruding portion 5 in the axial direction of the main body 3, and extends along the circumferential direction of the main body 3 so as to surround the main body 3 over the entire circumference.
The concave-convex portion 9 is composed of a concave portion 11 formed of a concave curve in a vertical cross-sectional view including the axial direction and a convex curve in a vertical cross-sectional view including the axial direction, and the rear end of the concave portion 11 in the axial direction. It has a convex portion 13 which is continuous with the above.

Since the horseshoe-shaped vortex is generated by the interference between the boundary layer of the flow and the protrusion 5, the generation of the horseshoe-shaped vortex can be suppressed by suppressing the development of the boundary layer. In this regard, according to the above configuration, the concavo-convex portion 9 provided on the outer surface of the main body 3 is composed of a concave curve and a convex curve in a vertical cross-sectional view, and the flow of fluid along the concavo-convex portion 9 is As shown in FIG. 4B, the fluid is reduced after passing through the uneven portion 9. Therefore, the uneven portion 9 can increase the flow velocity of the boundary layer flowing along the uneven portion 9, and as roughly shown in the graph of FIG. 4A, the thickness of the boundary layer is reduced to about half. Can be thinned to. As a result, the development of the boundary layer is suppressed and the formation of horseshoe-shaped vortices is suppressed, so that the formation of a non-uniform flow field is also suppressed. As a result, the underwater vehicle 1 having the above configuration is excellent in quietness because the generation of fluid noise in the propeller 7 as a propeller is suppressed.

In some embodiments, the curved surface forming the concave portion 11 and the curved surface forming the outer surface portion of the main body 3 connected to the front end of the concave portion 11 in the axial direction form a continuous curved surface, and between these curved surfaces. It is continuous up to the first derivative in the connecting line of.
Similarly, in some embodiments, the curved surface forming the concave portion 11 and the curved surface forming the convex portion 13 form a continuous curved surface, and are continuous up to the first derivative in the connecting line between these curved surfaces. ..
Similarly, in some embodiments, the curved surface forming the convex portion 13 and the curved surface forming the outer surface portion of the main body 3 connected to the rear end of the convex portion 13 in the axial direction form a continuous curved surface. It is continuous up to the first derivative in the connecting line between these curved surfaces.

In some embodiments, as shown in FIGS. 3 and 7, the concave curve constituting the recess 11 in vertical cross-sectional view is composed of an arc A1 having a constant radius of curvature R1. The convex curve forming the convex portion 13 in the vertical cross-sectional view is composed of an arc A2 having a constant radius of curvature R2.

In some embodiments, as shown in FIGS. 3 and 7, the concavo-convex portion 9 is composed of only the arc A1 and the arc A2 in the vertical cross-sectional view, and the length of the concavo-convex portion 9 in the axial direction is Lt. When the length of the recess 11 in the axial direction is L1, the ratio L1 / Lt of the length L1 to the length Lt is 0.2 or more and 0.5 or less.
According to the above configuration, when the ratio L1 / Lt is 0.2 or more and 0.5 or less, the flow velocity of the boundary layer is increased while surely suppressing the peeling of the boundary layer in and around the uneven portion 9. be able to.

In some embodiments, the concavo-convex portion 9 is composed of only the arc A1 and the arc A2 in a vertical cross-sectional view, the height of the concavo-convex portion 9 in the radial direction of the main body 3 is Ht, and the height of the concavo-convex portion 9 is behind the concavo-convex portion 9. When the outer diameter of the main body 3 is Db, the height ratio Ht / Db is 0.08 or more and 0.22 or less.
According to the above configuration, since the height ratio Ht / Db is 0.08 or more and 0.22 or less, the flow velocity of the boundary layer is reduced while surely suppressing the peeling of the boundary layer in the uneven portion 9 and its surroundings. Can be faster.
The radial direction of the main body 3 is a direction orthogonal to the axis Ax.

In some embodiments, the body 3 has a torso 15 and a head 17, as shown in FIGS. 1, 3, 4 (b), 5, 7, and 8.
The body portion 15 has a cylindrical shape and is located in the middle of the main body 3 in the axial direction. The protruding portion 5 protrudes from the body portion 15. The cross-sectional shape of the body portion 15 does not have to be a perfect circular shape.
The head 17 projects forward from the body 15 in the axial direction. The outer diameter of the head portion 17 gradually decreases as the distance from the body portion 15 increases in the axial direction.

In some embodiments, the uneven portion 9 is located on the head 17, as shown in FIGS. 1, 3 and 4 (b).
According to the above configuration, since the uneven portion 9 is formed on the head 17, the development of the boundary layer is suppressed and the horseshoe-shaped vortex is generated by a simple configuration without changing the shape of the body portion 15. It can be suppressed.

In some embodiments, the uneven portion 9 is located on the body portion 15, as shown in FIGS. 5, 7, 8 and 9.
According to the above configuration, since the uneven portion 9 is formed on the body portion 15, the uneven portion 9 can be arranged near the protruding portion 5. As a result, the thickness of the boundary layer can be reduced near the protrusion 5, so that the thickness of the boundary layer that interferes with the protrusion 5 can be further reduced. As a result, the formation of horseshoe-shaped vortices can be further suppressed.

In some embodiments, as shown in FIG. 7, the distance ratio D / Ht is 1 or more and 10 or less, where D is the distance between the uneven portion 9 and the protruding portion 5 in the axial direction.
According to the above configuration, since the distance ratio D / Ht is 1 or more and 10 or less, the uneven portion 9 is arranged near the protruding portion 5. As a result, the thickness of the boundary layer can be reduced near the protrusion 5, so that the thickness of the boundary layer that interferes with the protrusion 5 can be further reduced. As a result, the formation of horseshoe-shaped vortices can be further suppressed.

In some embodiments, the outer surface of the body 3 further has a plurality of dimples 19 in the axial direction in front of the protrusions 5, as shown in FIG.
According to the above configuration, the circulation flow (separation foam) is generated in the dimple 19, so that the flow of the fluid along the outer surface of the main body 3 is not in contact with the solid wall but in contact with the fluid (circulation flow). become. Therefore, the development of the boundary layer is suppressed by the plurality of dimples 19. As a result, the formation of horseshoe-shaped vortices can be further suppressed.

In some embodiments, the outer surface of the body 3 further has at least one circumferential groove 21 in the axial direction anterior to the protrusion 5 as shown in FIG.
According to the above configuration, the circulating flow (separation bubbles) is generated in the circumferential groove 21, so that the fluid flow along the outer surface of the main body 3 is not in contact with the solid wall but in contact with the fluid (circulating flow). Will be done. Therefore, the development of the boundary layer is suppressed by at least one circumferential groove 21. As a result, the formation of horseshoe-shaped vortices can be further suppressed.

The present invention is not limited to the above-mentioned some embodiments, and includes a form in which some of the above-described embodiments are modified and a form in which these embodiments are appropriately combined.
For example, in the above-described embodiment, the uneven portion 9 is formed on either one of the body portion 15 and the head portion 17 of the main body 3, but the uneven portion 9 is formed on both the body portion 15 and the head portion 17. You may be. That is, at least one uneven portion 9 may be formed.

1,1a ~ 1d Underwater Navigating Body 3 Main Body (Hull)
5 Protruding part 7 Propeller 9 Concavo-convex part 11 Concave part 13 Convex part 15 Body part 17 Head 19 Dimple 21 Circumferential groove Ax Axis A1, A2 Arc R1, R2 Radius of curvature

Claims (4)

The main body extending in the axial direction and
A protruding portion protruding from the main body in a direction orthogonal to the axial direction,
A propulsion device located behind the protrusion in the axial direction,
With
The outer surface of the main body includes at least one uneven portion extending so as to surround the main body along the circumferential direction of the main body in front of the protruding portion in the axial direction of the main body.
The at least one uneven portion
A recess formed by a concave curve in a vertical cross-sectional view including the axial direction, and a recess
A convex portion formed by a convex curve in a vertical cross-sectional view including the axial direction and connected to the rear end of the concave portion in the axial direction.
Have,
The front end of the protrusion in the axial direction is located closer to the front end than the rear end of the main body in the axial direction .
When the height of the uneven portion in the radial direction of the main body is Ht and the distance between the uneven portion and the protruding portion in the axial direction is D, the distance ratio D / Ht is 1 or more and 10 underwater vehicle, characterized in that at most. The main body
With a tubular body and
A head protruding forward from the body in the axial direction,
Including
The underwater vehicle according to claim 1, wherein the at least one uneven portion includes an uneven portion located on the head. The main body
With a tubular body and
A head protruding forward from the body in the axial direction,
Including
The underwater vehicle according to claim 1 or 2, wherein the at least one uneven portion includes an uneven portion located on the body portion. Any of claims 1 to 3, wherein the outer surface of the main body further has one or both of a plurality of dimples and at least one circumferential groove in front of the protrusion in the axial direction. The underwater vehicle according to item 1.

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