RU2607135C2 - Aft end of ship stabilized for storm sailing - Google Patents

Abstract

FIELD: ship building.

SUBSTANCE: invention relates to ship building, particularly, to designing ship hull aft end shape, used in complex storm and ice conditions of navigation. Disclosed is a aft end of the ship stabilized for storm navigation, formed by a stern post and stern counter, made in one-or twin screw version of the propulsors installation with possibility of using wing stabilizers of the remaining rolling and pitching motion and with two helical surfaces configuration for hydrodynamic stabilization of running pitch on calm water and under conditions of intense storm waves: first – at the level of variable waterlines with length from the tumble home of frames on board bulges to sharpened aft end scale of the cruiser stern, and second helical surface resting on keel line with twisting of water flow in opposite direction from under the bottom upwards in the zone of propeller-rudder complex, bilge entrance lines during conjugation of said helical surfaces creates conditions of mutual compensation of vortex flows under stern counter, that is required for general stabilization translational flow and damping of external wave disturbances in the zone of roll rudders and stabilizers action.

EFFECT: invention promotes better navigation and low rolling in conditions of intense storm waves, prevents spray icing top decks and causes the possibility of independent navigation in moderate ice.

1 cl, 2 dwg

Description

The invention relates to the field of the sciences of shipbuilding and navigation in difficult, stormy and ice conditions of navigation, and is the result of mathematical research using a series of experimental nautical tests of ship models carried out in support of new marine engineering developments and the provisions of the target consistent design of ships and ships for storm and ice conditions of navigation in the Russian Far East; to ensure navigation in the polar waters of the Arctic and Antarctic.

Appointment

The present invention establishes the contours and the shape of the aft end of a ship of increased storm seaworthiness and ice patency, which has the properties of hydrodynamic compensation of the running trim in quiet water, with proper moderation of all types of rolling under the influence of intense trochoidal waves of the open sea, and capable of active maneuvering with a given speed and direction movement in conditions of hurricane winds and intense storm waves, and with the possibility of autonomous ice swimming in ice with medium (incomplete) cohesion.

The ocean fleet of increased stormy seaworthiness and ice patency should be created according to special projects for the Far Eastern seas of Russia, which is necessary for the organization of effective marine operations and maintenance of transport communications in all seasons of the year in any weather conditions and which is largely due to the practical absence of refuge ports shelters from storms of ships and vessels intended for marine operations in the vast waters of Sakhalin and the Kuril Islands.

State of the art

The consistent design of marine equipment uses knowledge from the experience of good marine practice and engineering approaches to optimizing the contours, hull shape and general ship architecture of an all-weather vessel capable of the active use of deck devices and high-tech avionics in stormy rolling and cold winds of the northern seas [1].

The concept of target design and construction of a promising vessel is reduced to strict control of compliance with the initial operational task to achieve the highest efficiency in fulfilling tasks for the ship’s purpose, conducting offshore operations and maintaining maritime transport communications in all seasons of the year in any weather conditions of long autonomous navigation in remote storm and ice the waters of the Far Eastern seas of Russia and the North Pacific [2].

The engineering and technical principles [3] of non-resistance to force from storms and reduction of shock ice loads are used as the leading concept for the design of contours and the shape of the ship’s hull, which contributes to the hydrodynamic mutual compensation of all types of rolling, ensuring comfortable crew habitation and unconditional safety of cargo and equipment securing . The consistency of the hydrodynamic influence of the shape, inertia and gravitational mass of the ship on the move under stormy waves creates the necessary conditions to maintain the possibility of all-weather operation of the ship in accordance with the intended purpose.

The optimality of the choice of the contours of the ship as a whole and its aft end was verified by a series of calculations [4] using the Michell integral [5], the physical and geometric interpretation of which reveals the relationship between ship wave formation at high speeds and force impact on the ship’s hull from sea waves:

- соотношение длин для максимальной поперечной волны Λ к расчетной фазовой волне λ; k=2⋅π/λ - волновое число для данной фазовой волны;

- круговая частота расчетной волны во времени.where R _x is the wave resistance of the ship at a speed of movement V ₀ . All values in the Michell integral are reduced to dimensional physical functions and arguments: A (λ) is the amplitude of the radiated ship wave;

- the ratio of the lengths for the maximum transverse wave Λ to the calculated phase wave λ; k = 2⋅π / λ is the wave number for a given phase wave;

- circular frequency of the calculated wave in time.

, где Λ - длина поперечной корабельной волны, соответствующая скорости хода V₀. В оконечностях корабельной волне не хватает скорости для отрыва от корпуса, и волновые процессы заменяются суммированием амплитуд коротких волн в виде простого источника жидкости вблизи судовой обшивки.The physico-geometric interpretation of the hydrodynamic processes in the Michell integral shows the mechanism of reflection of external waves from the ship’s hull, incident on the ship’s hull at oblique angles ϑ in a range of lengths:

where Λ is the transverse ship wavelength corresponding to the speed V ₀ . At the ends of the ship’s wave, there is not enough speed to detach from the hull, and wave processes are replaced by summing the amplitudes of the short waves in the form of a simple source of liquid near the ship’s skin.

The optimization of the contours is reduced to the search for geometric shapes for the passage of a storm trochoidal wave through the ship's hull with minimal distortion. Computational experiments and nautical tests to simulate ship wave formation and the impact of trochoidal storm waves on the hull [6] confirm that the shape of the bow of the hull has the main influence on the storm seaworthiness of the hull, while private and substantially contradictory design conclusions are possible on the contours of the aft end. especially if the optimization design functionality is determined to take into account any one of the particular modes of practical operation of the vessel.

The present invention defines a unified and unified set of engineering solutions determined by the results of mathematical optimization, but relying more on subsequent refinement and experimental testing of the feed contours to achieve the best speed and stabilization of pitching due to stormy waves, which are optimized in combination with the achievement of stable operation of the helical and stabilization complex under the stern supervision of the ship.

The hull is optimized primarily for autonomous navigation in conditions of intense waves under hurricane winds of the open ocean [2, 6], with partial consideration of the possibility and safety of the autonomous course of the vessel in ice (class UL or ULA) of average cohesion, up to 8-9 points, including including at a speed of six or more knots under the icebreaker wiring.

The prototype of this engineering solution should be considered the invention RU2384456 - “Hydrographic and patrol service ship” [7], which defines the purpose and operational features of the high storm seaworthy ship, taking into account the possibility of using Patent RU 2384457 - “Active stabilizer of the ship’s pitching and roll - storm emergency mover "[8] with an improvement in terms of creating a stabilized flow under the stern guard of the ship and the safety of impacts from floating ice debris x fields. The invention RU-2535382 - “Fishing vessel of the North Seas” [9] is presented as an analogue for the low-speed vessel variant, which describes the design of cruise stern to reduce pitching on courses with a trawl along the wave, as well as to achieve greater safety of the trawl team’s work in conditions of intense waves stormy winds. Mighty ships and vessels of the late XIX - early XX centuries that did not have a transom stern are considered historical analogues for the proposed engineering solutions for the formation of the stern end of the ship, under the conditions of the need to maintain propulsion and prevent the stern end from being captured by the storm wave (broaching) while maintaining the course at arbitrary courses relative to the intense storm unrest and hurricane winds in deep water in the open ocean.

The implementation of the invention

The stern shaft and stern clearance of the ship are improved for all-weather navigation in conditions of intense waves under the hurricane winds of the open ocean, taking into account the need for an autonomous course in ice of medium cohesion.

In order to achieve the best speed and maneuverability in intense stormy waves, to provide the possibility of autonomous navigation in ice conditions of the Russian Far Eastern seas, acuten rod, sternal cheekbone and the glide of the propeller-driven complex of a high-altitude storm-displacement ship are arranged in single- or twin-screw propulsion installation (Fig. 1, 2 ), including with the ability to install and use active stabilizers of residual keel and rolling in accelerated flows directly beyond the heat propellers [2], which, when an emergency stop of the main machines automatically begin to work as storm fin propulsors.

Hydrodynamic stabilization of the stern of the ship provides the ability to move in quiet water without running trim, which is consistent with the requirement to minimize external force from storm waves, and the surface volume above the stern sink is significantly reduced, which minimizes external forces during storming on large waves without running and as a result, provides the ability to work emergency fin propulsion.

Ship wave formation, as well as the effect of storm waves, refers to the side skin band at the levels of variable water lines washed by the vertical and keel pitching. In this strip of waterlines, a helical surface is created, from the side bullets to the aft gap, for swirling and partially redirecting the flow near the side skin upwards, which helps to compensate for the satellite (hydrostatic) rarefaction and prevent separation of the high-frequency component of the ship wave; followed by a dispersion concentration of wave energy in the long-period part of the spectrum with a phase shift for the damping interference with the main component of wave formation - the transverse ship wave. Such a helical surface at the level of variable waterlines forms a small surface volume and a natural sharpening of the shell under the cruise stern of the ship, which is required to moderate the pitching and pitching; to prevent impacts and dangerous seizures of the stern of the ship (broaching) by the crests of the ninth shafts during courses along the wave in small strokes or in cases of emergency loss of travel, and also helps to maintain a slightly distorted field of storm waves under the aft control when the main engines stop, which automatically switches the keel and onboard dampers pitching in the mode of storm emergency propulsion for keeping the ship on a given course under the thrust of rigid swinging wings on elastically rotating horizontal balloons.

Sharp cruise food does not distort the hydrodynamic field of water flows in storm waves under the aft control of the hull when the main machines stop, which automatically switches the active dampers of pitching and onboard rolling to passive storm emergency wing propulsion to bring the ship to a safe storm course, for which the general device and the shape of the stern end must be optimized to maintain controllability even with the minimum traction that occurs with vertical spans of the stern end numbness as a result of the elastic reaction of the balloons on passive wing propulsion devices;

The second helical surface, with an axial line along the keel of the ship, serves to create a swirling flow from under the bottom of the ship in the direction of the shaft. On this helical surface, countercurrent spinning of a significantly larger supporting flow occurs, which allows for the compensation of the lower and upper flowing at the level of alternating waterlines, swirling flows in the feed aft zone, in the area of the rudder and horizontal dampers of the residual (nonlinear) keel and side rolling of the ship. Both flows create the total component of the liquid flow velocity vertically upward at a small distance from the side skin, which prevents the drawing of broken ice from the side of the side boules into the area of the feed rotor and stabilizing complex, and, as a result, hydrodynamic conditions arise for creating a stable ice channel behind the stern of the ship .

The above design features, in a single set of engineering and technical solutions, contribute to the improvement of propulsion, maneuverability and moderate heaving under conditions of intense stormy waves, and also make it possible to autonomously navigate in the mode of ice cutting in moderate ice, in which the main machines separate or break apart without prolonged stress ice fields of relatively small thickness.

Brief Description of the Drawings

FIG. 1. The feed cheekbone, the clearance, the shell and the shaft of the single-rotor ship, optimized for minimizing the running trim, ship wave formation and, as a result, the expected reduction in force impact on the ship from the side of storm waves due to the passage of storm trochoidal waves through the ship’s hull with minimal distortion, and that, in the case of stopping the propellers, provides a large range with vertical components of the fluid velocities in the crests of the storm waves necessary to activate the cr spruce dampers of pitching and rolling as passive storm wing propulsors on elastically rotating horizontal ballers. The single-rotor scheme of the rotor-propeller complex has a cantilever design of the aft sink, which is required to prevent exposing the propeller in conditions of intense pitching in stormy swimming.

FIG. 2. The feed cheekbone, the clearance, the shell and the shaft of the twin-screw ship, optimized for minimizing the running trim, ship wave formation and, as a result, the expected decrease in force impact on the ship from the side of storm waves due to the passage of storm trochoidal waves through the ship’s hull with minimal distortion, and that, in the case of stopping the propellers, provides a large range with vertical components of the fluid velocities in the crests of the storm waves necessary to activate the cr spruce dampers of pitching and rolling as passive storm wing propulsors on elastically rotating horizontal ballers. The twin-screw scheme of the propeller-steering complex allows to increase the completeness of the aft end of the ship, while due to the separation of the flows behind the propellers from the ship’s diametrical plane, the working conditions of the active stabilizers of the pitching are partially improved, while the regime of storm propulsors with widely spaced wings will contribute to some strengthening of the side pitching.

In the drawings, the numbers indicate the following structural features of ship's contours in the aft end of the ship:

1. A helical surface at the level of variable waterlines in the area of ship wave formation and reflection of storm waves from the ship's hull.

2. A helical surface that creates a compensating swirling fluid flow from under the bottom of the ship under the stern disgrace - into the area of the helm-steering and stabilizing wing complex.

3. The obstruction at the level of the operating waterline contributes to the hydrodynamic compensation of the ship’s pitching, and also intercepts the ice fields raised by the crest of the ship’s wave and prevents them from flooding and drawing into the area of the helm-steering complex in the aft part of the hull.

List of sources used

1. Vastly Khramushin. Features architecture of mean ship to navigation in heavy, stormy and ice conditions on the northern seas // Proceedings of the 14th International Ship Stability Workshop / Session 2 ^∧ Naval Ship Stability, 29 ^th September - 1 ^st October 2014, Kuala Lumpur, Malaysia. P. 47-57.

2. Krolenko S.I., Khramushin V.K. Key design decisions and features of storm navigating // Reports of a scientific and technical conference: “Problems of seaworthiness of ships, ship hydromechanics and offshore development” (XLIV Krylov readings). SPb .: Central Research Institute named after A.N. Krylova, Central Board of RosNTO shipbuilders named after A.N. Krylova, seaworthiness section of ships. November 15-16, 2011, St. Petersburg. S. 72-85.

3 Khramushin V.N. Research on optimizing the shape of the ship’s hull. Bulletin of the Far Eastern Branch of the Russian Academy of Sciences 2003, No 1 (107). S. 50-65.

4. "Hull" - Construction of the analytical form of the ship's hull, calculations of wave resistance, curves of the elements of the theoretical drawing and stability diagrams of ships. Computer program, No.2010615849 from 09/08/2010 (shipdesign.ru/SoftWare/2010615849.html)

5. Mr. J.N. Michell on the Wave-Resistance of a Ship. Philosophical Magazine, 1898, vol. 45, Ser. 5, pp. 106-123.

6. Khramushin V.H. Exploratory studies of the stormy seaworthiness of the ship (History of the evolutionary development of engineering solutions on the contours and architecture of the ship, on the unity of marine sciences and good marine practice). LAMBERT Academic Publishing GmbH & Co. Germany, 2011.288 c.

7. Khramushin B.H. Hydrographic and patrol service ship. Patent No. 2384456 dated 2010.03.20. shipdesign.ru/Invent/05.html

8. Khramushin V.N. The active stabilizer of pitching and rolling of the ship is a storm emergency propulsion. Patent No. 2384457 dated 2010.03.20. shipdesign.ru/Invent/04.html

9. Khramushin V.N. Fishing vessel of the northern seas. Patent No. 2535382 dated 2014.07.28 shipdesign.ru/Invent/07.html

Claims (1)

The aft end of the ship stabilized for storm sailing, formed by the after-rod and the aft gap, which is made in a single or twin-screw version of the propulsion system with the possibility of using wing stabilizers of the residual side and keel pitching, characterized by two screw surfaces for hydrodynamic stabilization of the running trim in quiet water and in conditions of intense stormy waves: the first - at the level of variable waterlines with a length from the blockout blockage on the side boules to the pointed aft shell of the cruise stern, and the second helical surface - resting on the keel line, with the water flow twisting in the opposite direction from under the bottom up into the area of the helical complex, the zygomatic contours when pairing these helical surfaces create conditions for the mutual compensation of the vortex flows under fodder clearance, which is required for the general stabilization of the translational flow and the suppression of external wave disturbances in the range of the rudders and stabilizers of the pitching, while the averaged The velocity range near the side plating is determined by the upward flow of water from under the hull, overpowering the vortex twisting from the bottom helical surface, which is important for protecting the propeller complex from impacts of large ice debris on the surface of the water and helps maintain the ice channel behind the stern of the ship.

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