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1
Content available Seakeeping software for the analysis of a ship’s seaworthiness
Cepowska Ż., Cepowski T.
Zeszyty Naukowe Akademii Morskiej w Szczecinie
|
2015
|
nr 42 (114)
95--100
EN
The article presents the Seakeeping research software, developed for the computation of a ship’s motions in regular and irregular waves on the basis of the following ship parameters: length between perpendiculars, beam, draught, block coefficient and transverse initial metacentric height. The software implements approximating functions of amplitude-phase characteristics of rolling, heaving, and pitching, developed by the author by means of artificial neural networks. The software determines transfer functions for the phenomena accompanying the rolling motion, such as slamming, green water, propeller surfacing, vertical acceleration forward and on the bridge. The article discusses possible uses of the software in scientific research, ship design and operation, and for educational purposes.
2
Content available remote Poziom emisji CO2 jako kryterium projektowe współczesnych statków transportowych
Szelangiewicz T., Żelazny K.
Prace Naukowe Politechniki Warszawskiej. Transport
|
2013
|
z. 98
625--635
PL
Od 2013 roku obowiązuje projektowy wskaźnik efektywności energetycznej (EEDI) dla nowych statków. Wartość tego wskaźnika dla określonego statku obliczana jest wg ustalonego wzoru i porównywana z tzw. linią referencyjną, która będzie zmieniana (obniżana) w następnych latach. Statki spełniające normy emisji CO2 będą uzyskiwały certyfikat energetyczny dopuszczający je do eksploatacji. W artykule przedstawiono możliwości obniżenia emisji CO2, a tym samym obniżenia wartości wskaźnika EEDI. Dokładniej przedstawiono propozycję modelowania i optymalizacji kadłuba statku, śruby napędowej i steru płetwowego w celu polepszenia sprawności napędowej statku, a tym samym obniżenia mocy napędu i emisji CO2.
EN
From 2013 onwards Energy Efficiency Design Index (EEDI) for new ships has been in force. The EEDI value for a given ship is calculated according to a standard formula and compared against a so called reference line which will be gradually decreasing in subsequent years (with CO2 emission levels getting lower). Ships conforming to the CO2 emission standards will be granted a validation certificate for exploitation. The article presents possible ways of lowering CO2 levels consequently resulting in smaller EEDI values as well. A more detailed description of hull design and optimisation of a propeller and a plane rudder to increase ship propulsion efficiency is offered in order to decrease ship propulsion power and CO2 levels.
3
Wpływ ujęcia wypornościowego kadłuba okrętu na drgania elementów układu napędowego
Charchalis A., Grządziela A.
Przegląd Mechaniczny
|
1998
|
nr 11-12
27-29
EN
The present-day fast warships have a relatively low rigidity of the hull structure. While the displacement changes, the deformation due to the different loads influences the deviations of the lines of the screw propeller shafts. Aligment of the shaft lines being a matter of consequence is submitted to periodic inspections. The autors attempt to make an analysis of how the real displacement influences the alignment errors and propose a diagnostic procedure.
4
Content available remote Theoretical investigation of the wake duct effectiveness
Tabaczek T.
Polish Maritime Research
|
1998
|
nr 3
6-9
EN
The effectiveness of cylindrical and elliptical wake ducts was investigated by using the theoretical methods. The method of surface vorticity distribution was applied to determine the velocity and pressure distributions on the surface of wake ducts in non-uniform stern flow. This method accounts for actual geometry of duct and hull surface with no simplifications. Velocity distribution at meridional sections of a duct was used in calculation of boundary layer parameters in accordance with the Turckenbrodt method. Relative effectiveness of different ducts was evaluated for a specific ship on the basis of the generated thrust and extent of flow separation.
5
Content available remote The present and possible application of the mean effective velocity in Ship Hydromechanics
Jarzyna H.
Polish Maritime Research
|
1998
|
nr 4
2-8
EN
The calculation results of the effective mean velocity from the old and proposed new definition are presented for comparsion. All consequences from state-of-art analysis and the proposed modification were numerically verified. The results of the model propulsion test BN18 bis formed the base of the numerical producers. The test was programmed with special care.
6
Content available remote The enhancement of seakeeping qualities of fast catamaran by means of stabilizing foils
Wełnicki W.
Polish Maritime Research
|
1998
|
nr 3
10-13
EN
Some aspects of insufficient seakeeping qualities of fast catamarans are commonly known. The intention of this investigations was to obtain quantitative data about the influence of application of hydrofoils on seakeeping qualities of a fast catamaran. Two types of foils were investigated: single foil spread between the hulls and double T - foils under the bows. Three locations of a single foil over the ship length and three angles of attack were tested. The comparsion was made between resistance, accelerations, heave and pitch in irregular head waves of the ship with and without foils. Quantitative effects of foils in different configurations and different sea and operation conditions were estimated.
7
Content available remote Strengthening the bulk carries corrugated bulkheads by fitting shedder plates
Bogdaniuk M., Dobrosielski T.
Polish Maritime Research
|
1998
|
nr 1
7-10
EN
Effectiveness of strengthening the bulkheads by fitting shedder or gusset and shedder plates is considered in the paper in connection with the new IACS unified requirement concerning the strength of the foremost corrugated bulkheads of existing bulk carriers in flooding conditions. The requirement will compel shipowners to strengthen bulkheads in many ships. The considerations are illustrated by results of the finite element method (FEM) calculation of stresses in bulkhead corrugations under lateral load in flooding conditions.
8
Content available remote Experimental assessment of critical stability parameters related to wave height
Frąckowiak M.
Polish Maritime Research
|
1998
|
nr 2
6-9
EN
In the period of 1992-94 the team of Ship Hydromechanics Division, Technical University of Gdańsk carried out experiments with the free runnig ship model on the lake in various weather conditions. The aim of the model tests was to collect information about ship capsizing related to significant wave height and various stability parameters. The procedure of carrying out the investigations is described. Stability criteria in function of the wave height were established onthe basis of the experimental results. Compliance with the proposals is expected to protect the ship against capsizing at sea if the wave conditions are known.
9
Content available remote Effective mean velocity (EMV) and effective mean pitch (EMP) based on a common definition
Jarzyna H.
Polish Maritime Research
|
1998
|
nr 3
2-5
EN
A definition is given of the effective mean velocity (EMV) in model propulsion test, being simultaneously the definition if effective mean pitch (EMP). In this way it is possible to replace the radial pitch distribution of a SB-propeller in behind condition by a constant pitch of a SBmod propeller in an uniform velocity which is the effective mean velocity univocally determined, independent of the averaging criteria (thrust, torque, or power identity).
10
Content available remote Design and analysis of surface piercing propellers
Szantyr J.
Polish Maritime Research
|
1998
|
nr 1
2-6
EN
The surface piercing propellers are promising propulsors for high speed craft, already proven by many full scale applications on small racing and sports boats. This paper presents newly developed theoretical procedures for design and hydrodynamics/strength analysis of such propellers. The design procedure is based on the lifting line theory while the analysis is performed by means of the lifting surface/finite element method. These procedures are confroted with the results of a series of model experiments by which surface piercing propellers were thoroughly tested in single and twin screw configurations. This confrontation demonstrates correctness of the basic theory and practical value of the design and analysis procedures.
11
Content available remote CTO and SVA joint research project on computation of ship flow phenomena
Bugalski T.J., Abdel-Maksoud M.
Polish Maritime Research
|
1998
|
nr 4
9-12
EN
The raport describes results of Ship Design and Research Centre Gdańsk (CTO, Poland) - Schiffbau Versuchanstalt Potsdam (SVA, Germany) joint research project on computations with the use of BOS-L and SHIP-FLOW numerical model basins. The subject of the project was application of CFD methods to studying the phenomena of ship flow. Results of the flow parameter computations for four different ship models (two from CTO and two from SVA) are presented. Some calculation results are compared with experimental data.
12
Content available remote A modification of distorion - energy strength theory at static-periodic loading conditions
Kolenda J.
Polish Maritime Research
|
1998
|
nr 2
2-5
EN
The aim of this paper is to present the analytical procedure capable of dealing with complex stress patterns in the high-cycle fatigue regime formed simultaneously by static fatigue regime formed simultaneously by static and periodic loads. It consists in modelling the actual multiaxial stress by means of the equivalent in-phase stress, transforming the equivalent stress into the reduced stress, and in using the reduced stress to fatigue assessment of the structural element by means of the formulae accepted in the case of simple sinusoidal stress. The reduced stress is determined with the aid of the average-distortion-energy strength hypothesis based on the distortion-energy strength theory. Thereby the mean stress is taken into account and the cycle counting is avoided.
13
Content available remote Pomiary chropowatości części podwodnej kadłuba a wymagania armatorów
Kania C.
Ochrona przed Korozją
|
1998
|
nr 1
2-4
PL
W artykule przedstawiono zagadnienia chropowatości części podwodnej kadłuba i jej wpływ na hydrodynamiczną charakterystykę hadłuba. Omówiono budowę i zasadę funkcjonowania przyrządu do pomiaru chropowatości oraz sposób interpretacji wyników. Przytoczono wyniki pomiarów chropowatości części podwodnej kadłuba na przykładzie kilku statków budowanych w polskich stoczniach w ciągu ostatnich kilku lat.
EN
The paper presents problems of hull underwater part roughness and its effect on the hydrodynamics characteristic of a ship hull. Construction and principle of operation of the roughness measuring instrument and a method of results interpretation are described. Results of measurements of hull underwater part roughness on a example of a number of ships huilt in Polish shipyards in the last few years are quoted.
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