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Wyszukujesz frazę "ship motion" wg kryterium: Temat


Wyświetlanie 1-11 z 11
Tytuł:
New concept of numerical ship motion modelling for total ship operability analysis by integrating ship and environment under one overall system
Autorzy:
Olszewski, H.
Ghaemi, H.
Powiązania:
https://bibliotekanauki.pl/articles/259338.pdf
Data publikacji:
2018
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
ship motion modelling
ship operability
total system
Opis:
The paper presents a new concept of overall ship motion modelling for application to total ship operability. The delivered model is a multi-phase and includes both submerged part of ship’s hull and the surrounding water as a unique body. The Discrete Finite Element Method is applied. The model is successfully examined and illustrated for a selected AHTS.
Źródło:
Polish Maritime Research; 2018, S 1; 36-41
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modelling of lake waves to simulate environmental disturbance to a scale ship model
Autorzy:
Rak, Andrzej
Miller, Anna
Powiązania:
https://bibliotekanauki.pl/articles/34614624.pdf
Data publikacji:
2023
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
wave modeling
environmental disturbances
scale ship model
ship motion simulation
Opis:
In the development of ship motion control systems, software simulations or scale model experiments in pools or open water are very often carried out in the verification and testing stages. This paper describes the process of building a software wave simulator based on data gathered on the Silm Lake near Iława, Poland, where scale ship models are used for research and training. The basis of the simulator structure is a set of shaping filters fed with Gaussian white noise. These filters are built in the form of transfer functions generating irregular wave signals for different input wind forces. To enable simulation of a wide range of wind speeds, nonlinear interpolation is used. The lake wave simulation method presented in this paper fills a gap in current research, and enables accurate modelling of characteristic environmental disturbances on a small lake for motion control experiments of scale model ships.
Źródło:
Polish Maritime Research; 2023, 3; 12-21
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Determination of seakeeping performance for a case study vessel by the strip theory method
Autorzy:
Niklas, Karol
Karczewski, Artur
Powiązania:
https://bibliotekanauki.pl/articles/1573815.pdf
Data publikacji:
2020
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
ship design
seakeeping
ship motion
added resistance
towing tank
strip theory
Opis:
The increase of seakeeping performance is of particular importance for car and passenger ferries, service ships in the gas and oil extraction industry and offshore wind power farm industry, as well as for special purpose ships (including military applications). In the water areas of the Baltic Sea, North Sea, and Mediterranean Sea, which are characterised by a short and steep wave, the hull shape has a substantial impact on the operational capacity and propulsion efficiency of the ship, as well as on comfort and safety of navigation. The article analyses selected aspects of seakeeping for four variants of a selected case study vessel, indicating practical limitations of the strip method. The analysed aspects included hull heaving and pitching, added resistance, Motion Thickness Indicator (MSI), and Subjective Magnitude (SM). Experimental tests were also performed in the towing tank. Their comparison with the numerical results has indicated high inaccuracy of the strip method. What is more, the simplified representation of hull shape used in the strip method makes it impossible to analyse the effect of hull shape changes on the predicted seakeeping characteristics. Especially for the case of head wave, neglecting highly non-linear phenomena, such as slamming or head wave breaking, in strip method-based computer simulations will significantly decrease the reliability of the obtained results. When using the strip method, the seakeeping analysis should be complemented with model tests in a towing tank, or by another more complex numerical analysis, such as CFD for instance.
Źródło:
Polish Maritime Research; 2020, 4; 4-16
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Reinforcement Learning in Discrete and Continuous Domains Applied to Ship Trajectory Generation
Autorzy:
Rak, A.
Gierusz, W.
Powiązania:
https://bibliotekanauki.pl/articles/259073.pdf
Data publikacji:
2012
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
ship motion control
trajectory generation
autonomous navigation
reinforcement learning
least-squares policy iteration
Opis:
This paper presents the application of the reinforcement learning algorithms to the task of autonomous determination of the ship trajectory during thein-harbour and harbour approaching manoeuvres. Authors used Markov decision processes formalism to build up the background of algorithm presentation. Two versions of RL algorithms were tested in the simulations: discrete (Q-learning) and continuous form (Least-Squares Policy Iteration). The results show that in both cases ship trajectory can be found. However discrete Q-learning algorithm suffered from many limitations (mainly curse of dimensionality) and practically is not applicable to the examined task. On the other hand, LSPI gave promising results. To be fully operational, proposed solution should be extended by taking into account ship heading and velocity and coupling with advanced multi-variable controller.
Źródło:
Polish Maritime Research; 2012, S 1; 31-36
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Prediction of power demand for ship motion control system of sea mining ship fitted with tubular winning system
Autorzy:
Bortnowska, M.
Powiązania:
https://bibliotekanauki.pl/articles/260362.pdf
Data publikacji:
2007
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
sea mining ship
tubular winning system
action of sea environment
thrust of ship propellers
power of ship motion control system
Opis:
One of the crucial systems of sea mining ship for poly-metallic concretions is its motion control system (SMC). Power of such system depends on sea environment characteristics and main dimensions of the ship. It can be expected that it will have important influence on total power of the ship’s power plant and in effect on the mining ship’s dimensions. In this paper is presented one of the possible ways of preliminary estimation of design power of SMC system for sea mining ship. Since details of design solution of such system for the ship in question are unknown (ships of the kind have not been built so far) the presented results should be considered to be the first estimation of the order of the power demand.
Źródło:
Polish Maritime Research; 2007, 4; 24-30
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical estimation of hull hydrodynamic derivatives in ship maneuvering prediction
Autorzy:
Kołodziej, Radosław
Hoffmann, Paweł
Powiązania:
https://bibliotekanauki.pl/articles/1551776.pdf
Data publikacji:
2021
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
captive model tests
CFD tools in maneuvering prediction
MOERI Container ship (KCS)
Hull hydrodynamic derivatives
Mathematical model of ship motion
Opis:
Prediction of the maneuvering characteristics of a ship at the design stage can be done by means of model tests, computational simulations or a combination of both. Th e model tests can be realized as a direct simulation of the standard maneuvers with the free running model, which gives the most accurate results but is also the least aff ordable, as it requires a very large tank or natural lake, as well as the complex equipment of the model. Alternatively, a captive model test can be used to identify the hydrodynamic characteristics of the hull, which can be used to simulate the standard maneuvers with the use of dedicated soft ware. Two types of captive model tests are distinguished: circular motion tests (CMT) and planar motion mechanism tests (PMM). Th e paper presents an attempt to develop a computational method for ship maneuverability prediction in which the hydrodynamic characteristics of the hull are identifi ed by means of computational fl uid dynamics (CFD). Th e CFD analyses presented here directly simulate the circular motion test. Th e resulting hull characteristics are verifi ed against the available literature data, and the results of the simulations are verifi ed against the results of free running model tests. Reasonable agreement shows the large potential of the proposed method.
Źródło:
Polish Maritime Research; 2021, 2; 46-53
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The influence of hydro-meteorological factors on the risk of harbour operations
Autorzy:
Abramowicz-Gerigk, T.
Powiązania:
https://bibliotekanauki.pl/articles/258690.pdf
Data publikacji:
2007
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
harbour operations
hydro-meteorological elements
model tests of self-berthing
real scale experiments
safety of navigation
ship motion simulation
Opis:
The paper presents a study on the environmental impact on the risk of harbour operations. The hydro-meteorological elements have been recognised as the most important safety factors with regard to the ship entrance into the harbour and berthing inside the docks. They are identified as real time, short and long term factors and they all should be considered in the safety assessment of harbour operations. The risk of each operation should be determined on the basis of weather forecast and the modelled prediction of the total water level, surface currents and waves. Several topics have been discussed in the paper with regard to the safe ship approach and navigation inside the harbour. The application of different tools for the prediction of ship performance is presented. The stochastic method for the determination of probability that the ship will navigate within the boundaries of the required navigational width and low speed manoeuvring standards proposed by Panel H-10 SNAME have been considered. The real scale experiments carried out in Port of Gdynia and the several trials performed using the Full Mission Simulator convinced that the open water model tests are necessary for the proper prediction of ship performance during berthing. The program of the proposed open water investigations is presented in the paper. The experimental stand constructed for the tests of ship-berth interactions, in the lake Silm at the Ilawa Ship Handling Training and Research Centre facilities is described.
Źródło:
Polish Maritime Research; 2007, S 2; 33-37
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The influence of ship rolling motion on take-off aerodynamic characteristics of aircraft
Autorzy:
He, Z.
Sun, X.
Gu, X.
Powiązania:
https://bibliotekanauki.pl/articles/259257.pdf
Data publikacji:
2018
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
ship rolling motion
ski-jump take-off
Meshless method
WALE turbulence model
aerodynamic characteristics
Opis:
Ship motion is an important factor affecting on the safety of ski-jump take-off. The simplified frigate ship SFS1 was numerically simulated, and the results were compared with the experimental data, the feasibility of the calculation method was verified; Meshless method and WALE turbulence model were used to simulate the process of aircraft skijump take-off, aerodynamic characteristics under different rolling conditions during the aircraft ski-jump take-off process were presented. The results showed that: the influence of ship rolling motion on lift coefficient, drag coefficient and pitching moment was small, side force and rolling moment were greatly affected by rolling motion; the region of downwash with the maximum speed was about 10 m from the bow; the safety of ski-jump take-off was greatly affected when aircraft was close to the bow within 20 m.
Źródło:
Polish Maritime Research; 2018, S 2; 23-29
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Determination of optimum hull form for passenger car ferry with regard to its sea-keeping qualities and additional resistance in waves
Autorzy:
Cepowski, T.
Powiązania:
https://bibliotekanauki.pl/articles/258898.pdf
Data publikacji:
2008
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
sea-keeping qualities
roll-on/roll-off ferry ship
rolling
transverse accelerations
vertical accelerations
motion sickness index
additional resistance in waves
ship hull form
ship design parameters
artificial neural networks
fuzzy logic
Opis:
This paper presents a method which makes it possible to determine optimum hull form of passenger car ferry with regard to selected sea-keeping qualities and additional resistance in waves. In the first phase of investigations a hull form characterized by the highest qualities was selected from the list of similar ships. Next, its optimum dimension ratios were determined. Design criteria were formulated by using a method based on deterministic scenarios, but objective functions of partial targets were determined in the form of artificial neural networks. To select the best design variants elements of fuzzy logic were used, that made it possible a.o. to show merits of the design by means of linguistic variables. Such approach made it possible to find the best hull form and its dimensions from the point of view of all considered criteria simultaneously.
Źródło:
Polish Maritime Research; 2008, 2; 3-11
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence analysis of changes of design parameters of passenger-car ferries on their selected sea-keeping qualities
Autorzy:
Cepowski, T.
Powiązania:
https://bibliotekanauki.pl/articles/259447.pdf
Data publikacji:
2010
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
passenger-car ferry
design guidelines
preliminary design stage
sea-keeping qualities
rolling
sea-sickness (motion-sickness) index
vertical accelerations
ateral accelerations
ship main dimensions
Opis:
The main scientific aim of this research was to elaborate design guidelines which could make it possible to improve sea-keeping qualities of passenger-car ferries. The searchedfor design guidelines were prepared in the form of regression functions as well as artificial neural networks on the basis of the results obtained from calculations with the use of numerical methods based on the theory of planar flow around a body. The guidelines make it possible to predict ship roll, sea-sickness index, lateral and vertical accelerations on the basis of quantities available in the preliminary stage of ship design.
Źródło:
Polish Maritime Research; 2010, 1; 25-32
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On the modeling of car passenger ferryship design parameters with respect to selected sea-keeping qualities and additional resistance in waves
Autorzy:
Cepowski, T.
Powiązania:
https://bibliotekanauki.pl/articles/258828.pdf
Data publikacji:
2009
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
sea-keeping qualities
roll-on/roll-off ferryship
rolling
motion sickness index
lateral accelerations
additional resistance in waves
ship design parameters
modeling
artificial neural networks
optimization
Pareto method
Opis:
This paper presents the modeling of car passenger ferryship design parameters with respect to such design criteria as selected sea-keeping qualities and additional resistance in waves. In the first part of the investigations approximations of selected statistical parameters of design criteria of ferryship were elaborated with respect to ship design parameters. The approximation functions were obtained with the use of artificial neural networks. In the second part of the investigations design solutions were searched for by applying the singleand multi-criterial optimization methods. The multi-criterial optimization was performed by using Pareto method. Such approach made it possible to present solutions in such form as to allow decision makers (shipowner, designer) to select solutions the most favourable in each individual case.
Źródło:
Polish Maritime Research; 2009, 3; 3-10
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-11 z 11

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