JPH01314686A - Lower tip structure of bow - Google Patents

Abstract

PURPOSE:To suppress wave making resistance as low as possible regardless of the sea surface condition or the draft of vessel by projecting a blade support forward from the lower tip of a bow and fixing a blade to the support. CONSTITUTION:A blade 1 having an attack angle against the flow is supported by a support 2 projecting forward at the lower end of a bow. When the blade 1 is moved under the water surface, water pressure at an obliquely lower region in the advancing direction of the blade 1 increases while the water pressure in the upper rear region of the blade 1 decreases thus lowering the water level simultaneously. When such structure is employed, water flow close to a bow outerboard 4 can be curved considerably downward or obliquely downward with low loss. Since wave making resistance and frictional resistance at the bow section are decreased and the mass of water around the blade 1 is relieves pitching, fuel consumption can be improved remarkably.

Description

Detailed Description of the Invention "Industrial Application Field" The present invention relates to the reduction of propulsion resistance of ships, and in particular to the reduction of wave-making resistance at the bow, and the lower tip of the bow for reducing frictional resistance by suppressing turbulence. Regarding structure.

"Conventional technology and its disadvantages" When a ship moves forward, the waves created by the bow create a large wave resistance, so as a measure to reduce or prevent this, conventional techniques have included adding a bulge (spherical shape) to the lower tip of the bow. thrust forward,
The so-called bulbous bow is well known.

To explain the working principle of a spherical bow using a drawing, for example, as shown in Figure 6, when a ball is moved under the water surface, the water pressure increases in the forward direction of the ball and the water surface rises, and vice versa behind the ball. Water pressure decreases and the water level drops. Taking advantage of this, the spherical bow has a spherical protrusion formed at the bottom tip of the bow, which moves the waves that would normally form just behind the bow forward, raises the water surface gently, and gives the appearance of a ship. Increase the length of the waves to reduce wave-making resistance. The waves generated by this spherical bow are different from the sudden waves created by the bow skin of a normal bow, and the water surface in a wider area in front of the bow rises more gently. , there is some effect in suppressing wave resistance.

However, this bulbous bow also has the following drawbacks. Firstly, the mound on the water surface at the bow cannot be suppressed to 1", and secondly, the flow on the upper surface of the spherical protrusion of the ship 1f is raised while rotating as shown in FIG. 7. The flow that rises from the bottom of Zunawara Lead White along the outer plate turns into a rotating flow, generating waves and changing the laminar flow in front of Lead White into a strong turbulent flow. This increases the boundary layer and increases the ship's resistance to Hf movement.This first drawback is particularly noticeable in large ships that are fully loaded and sail through waves.

``Object of the Invention'' The object of the present invention is to eliminate the drawbacks of the above-mentioned spherical bow and reduce the resistance during navigation of the ship. i+6
This is to minimize wave-making resistance no matter the surface situation or water flow of the ship.

[Structure and Working Principle of the Invention] The working principle of the bow lower tip structure of the present invention is slightly different from that of a ship with a spherical protrusion. As shown in Figure 6a, when the blade moves on the water surface, the water pressure in the diagonally downward area in the nij direction of the blade's traveling direction increases, while the water pressure in the -1 part rear area of the blade decreases. At the same time, the water surface rises. The present invention utilizes this principle of operation. The ship has a unique structure, with a vane plate at the lower tip of the bow at an angle of attack relative to the flow supported by a support member protruding forward. Naturally, it is important to provide sufficient clearance between the trailing edge of the wing and the bow skin for the flow to pass through. With this configuration, during navigation, it is possible to bend the flow in the vicinity of the lead-white outer shell downwardly or diagonally downwards with little resistance and in a comfortable manner. To explain with another example, when sending air to the bent wind barrel 11 as shown in Fig. 5a, a guide vane plate 8 as shown in Fig. 5a is provided, which does not reduce the resistance but maintains the same principle of operation. It is. At bends where the direction of the flow changes significantly, separation occurs in the flow as shown in Figure 5a, but the flow separation is reduced or prevented by the action of the guide vanes in Figure 5, and the overall flow is resistance decreases. The action of the vane of the invention is just like that of this guide vane. Furthermore, as shown in Figure 6a, when a blade is placed in a flow, a region of high pressure occurs slightly in the F direction in front of the blade.
A region of very low pressure occurs on the back of the wing, but this limited high-pressure region in front of the wing acts as if there were a protrusion there, much like the protrusion of a marlin or tuna. , increasing the apparent length and gently changing the direction of the flow. On the other hand, the strong negative pressure area on the back surface of the wing significantly suppresses the swelling of the water surface near the bow skin. This effect of suppressing the rise of the water surface naturally varies depending on the shape, size, and angle of attack of the wing plate, as well as the shape of the boat, the stiffness of the water, its speed, and the depth of the water. However, if the angle of attack of the blade becomes excessive due to various conditions, the flow behind the blade will separate, and the propulsion resistance will increase, which may even have a negative effect, so it is important to avoid flow separation. In order to prevent this, it is desirable to have a plurality of vanes whose angle of attack can be adjusted individually (i.e., by adjusting the angle of attack, the clearance can be adjusted accordingly. The planar shape is similar to that of an aircraft wing, and various shapes are possible, so there is no need to mention it specifically, but the purpose is to suppress wave resistance and smooth the flow around the bow shell. Therefore, it is natural to think of circles, ellipses, triangles, etc. with a width much narrower than that of an aircraft, and the cross-sectional shape can vary depending on the water area where the ship is sailing, the type of ship, and the water pressure that the wing plate receives. It is possible to consider a hollow structure.

"Example" Examples will be described below with reference to the drawings.

Figure 1a shows an example in which the wing plate supporting material 2 is welded to the steel bow shell 4, and the wing plates l are welded to the left and right sides of the wing plate 2. Tighten, glue,
Alternatively, it is conceivable to have the entire structure integrated with the hull. In the drawing, the wing plate 1 is attached to the wing plate support member 2 in the horizontal direction when viewed from the front, but depending on the shape of the bow and the speed of the ship, the wing plate 1 may be bent and attached in a figure 7 or U shape. can also be considered. Figure 1 shows a plurality of blade support members 2.
This is an example in which a wing plate] is supported on the inside of the wing plate, and during anchorage,
This is to prevent the anchor chain from coming into contact with the thin trailing edge of the wing plate 1 due to changes in the tidal current or the like. FIG. 2a shows an embodiment in which a plurality of blade plates 1 are attached to a blade support member 2 for the purpose of preventing flow separation, similar to the gap blade of an aircraft. Figure 2, c,
d, a cut 3b is made in the blade plate 1, a bulging process is made, and a blade plate l is formed.
The simplest example of work is shown in which a plurality of gaps 3a are provided in the body. FIG. 3 shows an example in which the protrusion of a conventional spherical bow 5 is regarded as the wing plate support material of the present invention, and the wing plate 1 is welded to both sides of the tip. This shows that it can be applied without major modification.

The point to keep in mind here is that if the thickness of the blade root l is increased and the blade length is shortened, the shape in plan view will resemble a conventional spherical bow, but there are clear differences between the two. , Figure 6a,
As shown in b, in the pressure distribution, the negative pressure region and the positive pressure region are distributed before and after the case of a spherical bow. In a member that overhangs from above, it is a point distributed below the
In the specific configuration, any of the elements that are characteristic of a general wing, such as a round leading edge, a sharp trailing edge, an angle of attack, and a camber, will be reflected in the member that protrudes from the protrusion to the left and right (the wing root 1 in Figure 3). The difference is whether or not it exists in the vertical cross-section in the bow direction of the member corresponding to .

FIG. 4 shows that the blade is attached to a hollow blade root support member 2 via a shaft 9, and the shaft 9 is connected to a hydraulic device 1 via a link mechanism 12.
0, and the angle of attack of the vane can be adjusted. In addition to a hydraulic system, the adjustment means may include a reach rod system, a gear system, and the like.

"Effects of the Invention" The structure of the present invention reduces wave-making resistance and frictional resistance at the bow, and the added mass of water around the blades alleviates pitching. Therefore, fuel efficiency is significantly improved. Furthermore, in order to reduce wave formation, the outer plate of the bow of a high-speed ship has traditionally been narrowed inward in a concave shape, but this narrowing can be relaxed, increasing the cargo carrying capacity. The structure of the present invention can be manufactured at a lower cost than a spherical bow or the like, so it has excellent economic effects. Note that the present invention is applicable to all floating structures, regardless of the presence or absence of an engine.

[Brief explanation of the drawing]

Figures 1a and 1b are perspective views of an embodiment of the bow lower tip structure of the present invention, Figure 2a is a side view of an example of a gap blade attached to a plurality of blade root supports, Figures 2, c, and d are a side view, plan view, and sectional view showing one way to create a gap wing; Figure 3 is a side view and sectional view of an example in which a wing plate is attached to a conventional spherical bow; Figure 4 is a partial cross-sectional side view of the embodiment showing how to adjust the angle of attack of the blade, Figures 5 a and b are explanatory diagrams showing streamlines inside the wind barrel, and Figures 6 a and b are views of the flow line in the flow. Figure 7 is an explanatory diagram of the pressure distribution around the placed wing and sphere, and Figure 7 is an explanatory diagram of the rotational flow created by the spherical bow. 1... Wing plate, 2... Wing plate support material, 3.3a... Gap, 4... Bow outer plate. 5-... Spherical bow, 6... Ball, 7... Wing, 8...
Guide blade root, 9... shaft, IO... hydraulic system, 11... wind barrel, 12...
・Link mechanism. 766-Procedural amendment (voluntary) 3 Relationship with the case of the person making the amendment Patent applicant Furibe Kiql Iwatai Address 495, 1-18 Seiwago, Kita-ku, Kobe City "Detailed description of the invention" of the specification to be amended Column 6: “Due to the shape of the ship and its material” on page 6, line 11 of the statement of contents of the amendment.
Insert the following 19 characters between ``change to welding'' and ``change to welding''.

Claims (3)

[Claims] (1) A lower tip structure of a bow, characterized in that a wing plate support member is protruded approximately forward near the lower tip of the bow, and a wing plate is attached to the wing plate support member. (2) The lower tip structure of a bow according to item 1, wherein the wing plate is attached to a wing support member so that the angle of attack of the wing plate can be adjusted. (3) A first feature in which the protrusion of the existing spherical bow is regarded as a wing support material, and the wing plate is attached to the protrusion.
The lower tip structure of the bow as described in Items 1 and 2.