JP4414793B2 - Ship - Google Patents

Description

The present invention relates to a ship with low propulsion resistance in waves, and more particularly to the structure of the bow portion of a ship having a bow valve.

  On large vessels such as tankers and bulk carriers, a bow valve (Bulbous Bow) is provided at the bow to reduce wave resistance in plain water. This bow valve is installed at the bottom of the bow to counteract the waves created by the hull in order to reduce the frictional resistance, pressure resistance, wave resistance, and air resistance among the components of propulsion resistance in plain water. Structure.

  And this bow valve shifts the position of the wave generated at the bow and makes it interfere well with the wave generated behind it, thereby reducing the overall wave resistance. In addition, the low-speed enlargement ship also has the effect of reducing the vortex resistance by adjusting the flow of water near the bow.

  However, as shown in FIGS. 17 to 20, in the conventional ship 1X provided with the bow valve 11X, the upper part thereof is retracted from the tip of the bow valve 11X and is advanced again by the upper deck 13X. For this reason, normally, the vicinity of the water surface at the time of navigation, such as the full load water line and the maximum water line, has a rounded and fertile shape and is often formed with a gentle curve with respect to the traveling direction.

  Therefore, in the actual sea area, the wave incident on the bow from the front is reflected almost forward by the bow, and the increase in resistance due to the reflection of the wave becomes large. At the same time, the resistance increases due to the waves generated by the movement of the hull in response to the waves. Therefore, in the actual sea area, the resistance in waves increases in addition to the resistance in plain water.

  In particular, in a large tanker such as a huge tanker, most of the waves generated in the actual sea area are shorter in wavelength than the captain and reflected at the bow, so the resistance in waves against propulsion resistance in plain water The rate of increase of will increase. For this reason, there is a problem that if seamazine is small, the navigation speed (ship speed) in the waves decreases. The sea magazine is a value obtained by dividing "the increase in horsepower necessary for navigating in the waves at a constant ship speed" by "plain water horsepower at the same ship speed".

  In order to reduce the increase in wave resistance of this enlargement ship, the bow part is sharpened as much as possible forward, and it is considered that the wave is not broken forward and it is divided side by side. An enlarged ship formed by sharpening the bow shape has been proposed (see, for example, Patent Document 1 and Patent Document 2).

  However, when a wave hits above the maximum waterline, it is mainly when the wave is full and the wave is high, and in light marine conditions and in calm sea conditions where the wavelength of the main component of the wave is relatively short compared to the captain, Since the waves do not hit, it is estimated that the effect of decreasing the resistance increase in waves is small except during stormy weather.

  Also, in order to improve the propulsion performance when sailing in the waves, it has a bow valve that protrudes forward from the bow perpendicular below the full load water line and an upper bow that protrudes forward from the bow vertical above the full water line. In a large-sized enlarged ship, a wedge-shaped appendage is attached to the end of the bow near the full load water line with the pointed edge facing forward and penetrating the flat water surface, and waves incident on the bow from the front during navigation in waves There has been proposed a large-sized enlargement ship equipped with means for improving propulsion performance in waves that can be divided into right and left at the tip edge of the wedge-shaped appendage to prevent the generation of reflected waves (see, for example, Patent Document 3).

However, as shown in FIG. 21, when the joint portion between the main hull 1Yb and the appendage 12Y is not smoothly connected and a discontinuity of the surface, that is, a bent portion Q occurs, a vortex is generated in the vicinity of the portion Q. There is a problem that V and a new wave W are generated, and resistance increases not only in flat water but also in waves.
Japanese Patent No. 3279284 Japanese Patent No. 3279285 Japanese Patent No. Hei 8-142974

  The present invention has been made to solve the above-described problems, and its object is to reduce an increase in resistance in waves by reducing a reflected wave with respect to an incident wave at a bow portion in a ship having a bow valve. It is to provide a ship that can improve propulsion performance.

In order to achieve the above object, the ship of the present invention is a ship having a bow valve, provided with a reflected wave reducing structure that can be attached as an appendage near the water surface above the bow valve, and the reflected wave reducing structure. In the shape of the water surface, the tip portion is provided at the same position as the tip of the bow valve or a position retracted from the tip of the bow valve, and has a curved surface that smoothly contacts the main hull, Furthermore, in the waterline surface shape, the shape of the connecting portion between the main hull and the reflected wave reducing structure is in the shape of an arc that touches both the main hull and the reflected wave reducing structure and has a center on the outside. The distance between the front end of the reflected wave reducing structure and the front end of the main hull is L1, the radius of the arc is 2 × L1 to 4 × L1, and the reflected wave reducing structure can be attached as an addition. Formed into In addition, a first line extending upward from the top of the tip of the bow valve to the first point intersecting the bow line and a horizontal line extending from the top of the tip of the bow valve horizontally to the hull form a smooth hull. A wavy structure that forms a heel-side surface with a second line connected to the line at a second point and a third line connecting the first point and the second point; It is configured as a feature .

  This reflected wave reducing structure can reduce the reflection of waves incident on the bow part of a ship having a bow valve, and it is difficult to generate vortices and waves at the connecting part with the main hull. What is necessary is just to divert an incident wave to the ship side direction, and to reduce reflection, and to form by forming the structure etc. which the waterline surface shape of a wave cutting part has an acute angle | corner in the curved surface which touches a main hull smoothly.

  The reflected wave reducing structure is provided in the vicinity of the water surface above the bow valve in a ship having a bow valve, that is, a ship having a spherical bow. The vicinity of the water surface above the bow valve is a portion that intersects the water surface and hits a wave when the ship sails.

  In general, the draft of a ship changes depending on the state of loading, and the water surface position relative to the bow also rises and falls. Here, it is desirable to include all the positions of the water surface encountered in the navigation of the ship, such as the draft part in the full load state and the draft part in the light load state, but even in the vicinity of the water surface only in some states, Since the effect can be exerted, it is not always necessary to include all the water surface positions encountered in the navigation of the ship.

  According to the ship of the present invention, a wave that is incident when the ship is navigating in the waves by the reflected wave reduction structure provided near the water surface above the bow valve in the bow part, that is, the ship. Since the reflection at the bow portion can be reduced, the increase in resistance due to the reflected wave can be reduced. In general, a structure that reduces reflected waves also reduces wave formation due to hull motion, thereby reducing resistance increase due to hull motion. Therefore, the propulsion performance in the waves is improved and the horsepower required for navigation is reduced, so that fuel efficiency and carbon dioxide reduction effects can also be obtained.

  In addition, since the reflected wave reducing structure is formed with a curved surface that smoothly contacts the main hull, it is possible to prevent the generation of vortices and waves at the connecting portion between the main hull and the reflected wave reducing structure, It is possible to prevent an increase in resistance in flat water and waves.

  In addition, if the tip of the reflected wave reducing structure is set back in the main hull direction rather than the tip of the bow valve instead of using the tip of the reflected wave reducing structure as the tip of the bow valve, the reflected wave reducing effect is somewhat reduced. However, the size of the adduct can be reduced.

  In addition, this reflected wave reducing structure is configured to be added to the bow structure designed as a bow valve hull form without almost deforming the bow valve shape, so it does not affect the conventional bow valve design method. Does not affect.

  In addition, the wave effect generated by the bow valve occurs deeper than the water surface during navigation, while the wave-making resistance generated by the reflected wave reducing structure is extremely small, so the bow valve and this reflected wave reducing structure The interference with is small. Therefore, the increase in resistance in plain water is extremely small, and the effect of reducing the increase in resistance in waves is greater.

  And in said ship, in the water line shape, the shape of the connection part of the main hull and the reflected wave reducing structure is in contact with both the main hull and the reflected wave reducing structure, and the arc having the center on the outside The distance between the front end of the reflected wave reducing structure and the front end of the main hull is L1, and the radius of the arc is 2 × L1 to 4 × L1.

  That is, in the waterline shape, the main hull and the reflected wave reducing structure are smoothly joined by an arc shape having a radius 2 to 4 times the length L1 of the reflected wave reducing structure so that the main hull and the reflected wave reducing structure are continuously and smoothly joined. It has a curved surface in contact with. According to this structure, it is possible to prevent the generation of vortices and waves at the connecting portion between the main hull and the reflected wave reducing structure, thereby preventing an increase in resistance in the plain water and in the waves. By setting the shape to an arc shape with a specific radius, the arc is determined according to the length L1 of the reflected wave reducing structure, and the entire shape is determined. Therefore, the design is simplified and the curved surface processing is also simplified because it is an arc. Become.

  If the radius of the arc is less than 2 × L1, the main hull will be contacted with a sharp curve, and the effect of preventing the generation of vortices and waves at the connecting portion will be insufficient. Also, if the radius of the arc is larger than 4 × L1, the length of the reflected wave reducing structure is substantially shortened from the relationship of the shape, and the reflected wave reducing structure is reduced. The effect of decreasing the resistance increase due to the reflected wave is insufficient.

  Further, the reflected wave reducing structure can be formed as a wave cutting structure. For example, the wave cutting structure is a target water surface (hereinafter referred to as a target water surface) where the wave cutting structure is intended to exhibit an incident wave reducing effect. The water line surface shape in the water surface is smaller than the water line surface shape in which the bow valve has the maximum area, or the front end portion of the target water surface is the same as or the rear side and the front end of the bow valve. The angle of the portion is formed to be smaller than the angle of the foremost end portion of the bow valve.

  In addition, this reflected wave reducing structure has an angle of the front end, that is, a tip angle of a certain degree or more, thereby avoiding over-extrusion of the tip and avoiding the length of the ship such as the inter-waterline length and the total length. Can be prevented from increasing significantly, and by making the angle smaller than that of the main hull (the hull when no reflected wave reducing structure is provided), the incident wave can be deflected to the side. The reduction effect can be obtained in a practical amount.

  Further, in the above-described ship, in a horizontal section of the reflected wave reducing structure, a front portion of the reflected wave reducing structure is formed in a triangular shape having a tip of the reflected wave reducing structure on a hull center line. That is, a structure having a triangular horizontal cross section is provided between the bow flare and the bow valve.

  Further, in the above-described ship, in a horizontal section of the reflected wave reducing structure, a triangle forming a front portion of the reflected wave reducing structure is within a range surrounded by a tangent line between the tip of the bow valve and the hull. Including and configuring.

  With this configuration, the degree of bow enlargement in the vicinity of the water surface of the bow decreases, so that an increase in resistance in the waves is reduced. Moreover, since the incident angle of the water line surface near the water surface of the bow becomes gentle, the wave-making resistance in plain water is also reduced.

  Further, the reflected wave reducing structure can be added not only to a new ship but also to an existing bow valve ship. In the case of a new ship, it is constructed as a part of the bow structure, and in the case of a modification of an existing ship, it can be additionally installed as a structure that covers the bow structure. In addition, when it is set as this additional structure, since watertightness is not required, it can add easily and can suppress the increase in the steel-material weight by the increase in the length between perpendiculars. The reflected wave reducing structure is also useful for protecting the bow portion.

  According to the ship of the present invention, the reflected wave reducing structure provided in the vicinity of the water surface of the bow part can reduce the reflection of the wave that is incident when the ship is navigating in the waves at the bow part. The increase in resistance due to the reflected wave and the increase in resistance due to the hull motion can be reduced. Therefore, the propulsion performance in the wave of the ship is improved and the horsepower required for navigation is also reduced, so that the fuel efficiency and the carbon dioxide reduction effect can also be obtained.

  In addition, since the reflected wave reducing structure is formed with a curved surface that smoothly contacts the main hull, it is possible to prevent the generation of vortices and waves at the connecting portion between the main hull and the reflected wave reducing structure, It is possible to prevent an increase in resistance in flat water and waves.

  This reflected wave reducing structure is additionally provided in the bow structure designed as a bow valve hull form with almost no deformation of the bow valve shape, thus affecting the conventional bow valve design method. Does not affect.

  Further, the reflected wave reducing structure can be added not only to a new ship but also to an existing bow valve ship.

  Further, in the waterline shape, the main hull and the reflected wave reducing structure are smoothly contacted by an arc having a radius 2 to 4 times the length L1 of the reflected wave reducing structure so that the main hull and the reflected wave reducing structure are continuously and smoothly joined. When formed by a curved surface, it is possible to prevent vortices and waves from being generated at the connecting part of the main hull and the reflected wave reducing structure, thereby preventing an increase in resistance in plain water and waves, and in addition, the shape of the connecting part Since the arc is determined according to the length L1 of the reflected wave reducing structure and the entire shape is determined by making the arc shape with a specific radius, the design is simplified, and the curved surface machining is also simplified because it is an arc, making the machining easier. .

  Hereinafter, embodiments of a ship according to the present invention will be described with reference to the drawings.

As shown in FIGS. 1 to 4, the ship of the first embodiment which is a reference of the present invention is a ship 1 having a bow valve (Barbus bow) 11 at the bow, and an incident wave reducing structure near the water surface of the bow part. A wave cutting part 12 which is a thing is provided and configured.

  The bow valve 11 is a structure in which the bow portion under the surface of the water is inflated in a bulb shape, and is formed in the shape of a bow valve formed in accordance with a normal bow valve design method, and is not deformed into a special shape in the present invention. .

  The wave cutting portion 12 is arranged above the bow valve 11 so as to include at least one portion corresponding to the height of the water surface (target water surface) that the ship 1 encounters during the voyage, if possible, including as wide a range as possible. Is done. 1 to 4 extends upward from the upper part of the bow valve 11 toward the upper deck 13 so as to include the entire range of water surface positions encountered. With this configuration, it is possible to cover the vicinity of the full load waterline and the vicinity of the lightly loaded waterline.

  For convenience, if the water surface when navigating in the full waterline is the target water surface for incident wave reduction, and not the water surface when navigating in other light load conditions, etc., near the full waterline that will be the target water surface In addition, the wave cutting part 12 is provided locally.

  The wave cutting portion 12 has a water surface shape as shown in FIG. 4, and is provided with a front end portion at the same position as the front end of the bow valve 11 and a curved surface that smoothly contacts the main hull. Formed. For example, the water line surface W2 protrudes from the water line surface (W2) when there is no wave cutting part 12, and the tip angle α of the water line surface W2 is also smaller than the tip angle α ′ of the water line surface (W2). It is formed.

  The wave cutting portion 12 has a portion immediately above the bow valve 11 smoothly and gradually thinned from the bow valve 11 and extends upward while maintaining the thin shape, gradually from the vicinity of the maximum water line toward the bow portion of the upper deck. It is formed so as to be smoothly connected to the water line surface W5 of this upper deck.

  Further, as shown in FIG. 2, the wave cutting portion 12 extends vertically from the tip portion of the bow valve 11 in a side view, and the target water surface W.V. L. It is configured to smoothly continue to the front end of the upper bow deck W5 above.

As shown in FIG. 5 to FIG. 7, the ship of the second embodiment that is a reference of the present invention is also a ship 1A having a bow valve 11A at the bow, but the shape of the wave cutting structure 12A is a reference. It differs from the shape of the wave cutting part 12 of the ship 1 of the form .

  This ship 1A is obtained by additionally providing a wave cutting structure 12A to the ship 1X shown in FIGS. 17 to 20, and this wave cutting structure 12A is, as shown in FIG. 6, the wave cutting structure 12A. Is provided so as to recede in the direction of the main hull from the tip of the bow valve 11A. In addition, (B1) in FIG. 6 and (W2) in FIG. 7 show a side cross-sectional shape and a water line surface shape when the wave cutting structure 12A is not provided.

As shown in FIGS. 8 to 12, the ship according to the embodiment of the present invention is also a ship 1 </ b > B having a bow valve 11 </ b > B at the bow, and the shape of the wave cutting structure 12 </ b > B is a reference. It differs from the shape of the wave cutting parts 12 and 12A of the ship 1,1A of the form.

  This ship 1B is obtained by additionally providing a wave breaking structure 12B to the ship 1X shown in FIGS. 17 to 20, and this wave cutting structure 12B is, as shown in FIG. Is provided at the position of the tip of the bow valve 11B. In addition, the dotted line in the figure of FIGS. 9-11 shows a front surface shape, a side cross-sectional shape, and a water line surface shape when not providing the wave cutting structure 12B.

  This wave cutting structure 12B extends horizontally from the upper portion Pa of the tip Bf of the bow valve 11B to a point La that intersects the bow line and the upper portion Pa of the tip Bf of the bow valve 11B to the hull. A starboard-side surface As is formed by a line Lb continuous at a point Pb to a line that smoothly forms a hull and a line Lc connecting the point Pc and the point Pb. Similarly, the port side surface Ap is formed.

  The front portion of the line Lb, preferably 30% to 80%, is formed by a straight line, and the rear portion and the upper portion are configured to be smoothly connected to the hull. If it is less than 30%, the workability deteriorates, and if it is more than 80%, it becomes difficult to smoothly connect the rear part to the hull.

  The width of the corrugated structure 12B, that is, the distance between the starboard side point Pb and the portside point Pb is preferably 5% to 40% of the ship mold width. If it is smaller than 5%, the effect is small, and if it is larger than 40%, the increase in resistance in plain water becomes too large, and the demerit becomes larger than the decrease in resistance increase in waves.

  With this configuration, in the horizontal cross section, the front portion of the hull center line C.I. L. The reflected wave reducing structure 12B formed in a triangular shape having the tip La on the top is obtained. That is, this wave cutting structure 12B is a structure provided between the bow flare and the bow valve 11B and having a triangular horizontal cross section at the front portion.

  This wave cutting structure 12B is configured such that, in its horizontal section, the triangle forming the front portion is included within the range surrounded by the tangent line Lt between the tip Bf of the bow valve 11B and the hull.

  The wave-cutting structure 12B having this configuration reduces the bow enlargement degree near the water surface of the bow, so that the increase in resistance in the waves is reduced, and the incident angle of the water line surface near the water surface of the bow becomes gentle. In addition, wave resistance in plain water is reduced.

Further, in the water line shape, as shown in FIG. 13, the shape of the connecting portion between the main hull 1Bb and the reflected wave reducing structure 12B is in contact with both the main hull 1Bb and the reflected wave reducing structure 12B. Let it be an arc Cr having the center on the outside. At the same time, the distance between the front end P1 of the reflected wave reducing structure 12B and the front end P2 of the main hull 1Bb is L1, and the radius RL of the arc Cr is 2 × L1 to 4 × L1.

  As a result, it is possible to prevent vortices and waves from being generated at the connecting portion between the main hull 1Bb and the reflected wave reducing structure 12B, thereby preventing an increase in resistance in plain water and waves, and the shape of the connecting portion. Since the arc Cr is determined according to the length L1 of the reflected wave reducing structure 12B and the entire shape is determined by making the arc shape Cr with a specific radius RL, the design is simplified and the curved surface processing is also simplified because it is an arc. Processing becomes easy.

  In the embodiment shown in FIGS. 8 to 11, the tip end La of the waved structure 12B is arranged immediately above the tip Bf of the bow valve 11B. However, as shown in FIG. The line La is formed by a straight line that is retracted from the tip Bf of the bow valve 11B, or, as shown in FIGS. 12B and 12C, the tip line La is a curved line having a concave or convex center in side view. Alternatively, it may be formed by a straight line inclined in the front-rear direction as shown in FIG.

The model ship of Example 1 which should be called the reference example which provided the bow shape provided with the wave cutting part 12 as shown in FIGS. 1-4, and the bow ship type which does not provide a wave cutting part as shown in FIGS. A comparative model ship was prepared, and a water tank test for increasing resistance in waves in a full state was conducted. The results of this water tank test are shown in FIG. In the figure, the horizontal axis represents regular wave (incident wave wavelength / length: λ / Lpp), and the vertical axis represents resistance increase coefficient in regular wave direction wave.

  According to the results of the water tank experiment, it can be seen that the example in which the wave cutting part is provided has significantly less resistance increase in waves than the comparative example in which the wave cutting part is not provided.

  As shown in FIGS. 8 to 11, a model ship of the second embodiment having a bow shape provided with a triangular wave-cut portion 12 </ b> B, and a bow shape having no triangular wave-cut portion as shown in FIGS. 17 to 20. The model ship of the comparative example prepared was prepared, and the water tank test of the increase in resistance in waves in the full load state and the wave resistance in flat water was conducted. The results of the water tank test for increasing the resistance in waves are shown in FIG. In the figure, the horizontal axis represents the regular wave (incident wave wavelength / length: λ / Lpp), and the vertical axis represents the same wave height when the Froude number (Fn) is 0.15 (Hw / Lpp = 0.123). The resistance increase coefficient in the regular wave direction is shown. Moreover, the water tank test result of resistance increase in plain water is shown in FIG. In the figure, the horizontal axis indicates the ship speed in a Froude number (Fn) display, and the vertical axis indicates the wave-making resistance coefficient in plain water.

  According to the results of these water tank experiments, it can be seen that Example 2 provided with the triangular wave-cut portion 12B has a remarkably small increase in resistance in waves compared with the comparative example not provided with the triangular wave-cut portion.

It is a perspective view of the bow part of the ship of the 1st form used as a reference of the present invention . It is a front sectional view which shows the shape of the bow part of the ship of FIG. It is a sectional side view which shows the shape of the bow part of the ship of FIG. It is a horizontal sectional view which shows the shape of the bow part of the ship of FIG. It is front sectional drawing which shows the shape of the bow part of the ship of the 2nd form used as the reference of this invention . It is a sectional side view which shows the shape of the bow part of the ship of FIG. It is a horizontal sectional view which shows the shape of the bow part of the ship of FIG. It is a perspective view of the bow part of the ship of an embodiment concerning the present invention . It is a front sectional view showing the shape of the bow portion of the ship of FIG. It is a sectional side view which shows the shape of the bow part of the ship of FIG. It is a horizontal sectional view which shows the shape of the bow part of the ship of FIG. It is a partial side view which shows the shape of the other bow part in the ship of embodiment which concerns on this invention , (a) is a receding linear shape, (b) is a concave curve shape, (c) is a convex curve shape. (D) shows an inclined linear shape. It is a horizontal sectional view which shows the shape of the connection part of the main hull of the ship of FIG. 12, and a reflected wave reduction structure. It is a figure which shows the resistance increase test result in the wave in the full load state of Example 1 which should be called a reference example, and a comparative example. It is a figure which shows the resistance increase test result in the wave in the full load state of Example 2 and a comparative example. It is a figure which shows the resistance increase test result in the plain water in the full load state of Example 2 and a comparative example. It is a perspective view of the bow part of the ship which has a bow valve of a prior art. It is a front sectional view which shows the shape of the bow part of the ship of FIG. It is a sectional side view which shows the shape of the bow part of the ship of FIG. It is a horizontal sectional view which shows the shape of the bow part of the ship of FIG. It is a horizontal sectional view showing the shape of the bow portion of the ship and the state of vortex generation.

Explanation of symbols

1,1A, 1B Ship 11,11A, 11B Bow valve (Barbasse bow)
12 Wave cutting part (reflected wave reduction structure)
12A, 12B Wave cutting structure (reflection wave reducing structure)
Cr arc shape
L1 Distance between the front edge of the reflected wave reduction structure and the front edge of the main hull
RL Arc radius

Claims (4)

In a ship having a bow valve, a reflected wave reduction structure that can be attached as an appendage is provided near the water surface above the bow valve. The reflected wave reduction structure is in a water surface shape, and a tip portion of the bow valve Provided to be the same position as the tip, or a position retracted from the tip of the bow valve, and has a curved surface that smoothly contacts the main hull,
Furthermore, in the waterline surface shape, the shape of the connecting portion between the main hull and the reflected wave reducing structure is in the shape of an arc that touches both the main hull and the reflected wave reducing structure and has a center on the outside. The distance between the front end of the reflected wave reducing structure and the front end of the main hull is L1, and the radius of the arc is 2 × L1 to 4 × L1 ,
The reflected wave reducing structure is formed so as to be attachable as an appendage, and a first line extending from an upper portion of the tip of the bow valve to a first point intersecting the bow line, and a tip of the bow valve A second line connecting at a second point to a line extending horizontally from the top of the ship to the hull and smoothly forming the hull, and a third line connecting the first point and the second point A ship comprising a wave-cut structure that forms a surface on the shore side . The ship according to claim 1, wherein 30% to 80% of a front portion of the second line is formed by a straight line . The ship according to claim 1 or 2, wherein a width of the wave cutting structure is 5% to 40% of a mold width of the ship. The first line at the tip of the corrugated structure is formed by a straight line retreated from the tip of the bow valve, a curved line with a concave or convex center in a side view, or a straight line inclined in the front-rear direction. Vessel according to claim 1, 2 or 3 wherein that.

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