Temat: Hydrodynamic Forces

Skocz do pozycji: 1.

Tytuł:: On hydrodynamic forces acting on the ship in large motions
Autorzy:: Błocki, W.
Tematy:: hydrodynamic forces
ship motions of large amplitudes
added forces; Pokaż więcej
Wydawca:: Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Powiązania:: https://bibliotekanauki.pl/articles/259385.pdf Link otwiera się w nowym oknie
Opis:: Present stale of mathematical description of ship dynamic non-linear behaviour is preŹsented in this paper with a view to avoiding excessive complications in solving the proŹblem. The non-linearity concerns first of all Froude-Krilov forces and damping forces occurring after entering ship's deck into water or those resulting from drag of bilge keels. And, to the remaining, accompanying and diffraction forces the linear extrapolation has been applied.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Experimental analysis of the effectiveness of ship propulsion devices
Autorzy:: Abramowicz-Gerik, T.
Tematy:: napędy okrętowe
modelowanie
siły hydrodynamiczne
ship propulsion
modelling
hydrodynamic forces; Pokaż więcej
Wydawca:: Polskie Forum Nawigacyjne
Powiązania:: https://bibliotekanauki.pl/articles/320536.pdf Link otwiera się w nowym oknie
Opis:: The paper presents the study on the effectiveness of ship propulsion devices based on model tests conducted in the open water experimental set up. The influence of the water depth to draft ratio and distance from the vertical tight wall on the hydrodynamic forces generated by the propellers on the ship hull was investigated. The interaction effects observed for the twin propeller ship in bollard pull condition were compared with the effects induced by single propeller vessels available in literature and discussed with respect to the mathematical modelling of hydrodynamic forces generated on the hull by ship propulsion devices.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Application of potential theory in calculating wave-induced vertical forces on horizontal cylinders near a plane boundary
Autorzy:: Marcinkowski, T.
Wilde, P.
Tematy:: hydrodynamic forces
underwater pipeline
potential theory
diffraction theory
curvilinear coordinates; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Budownictwa Wodnego PAN
Powiązania:: https://bibliotekanauki.pl/articles/241390.pdf Link otwiera się w nowym oknie
Opis:: Hydrodynamic forces acting on a horizontal cylinder located in the vicinity of the bottom are analyzed by a diffraction theory which solves the problem in terms of a velocity potential. The cylinder is assumed to be rigidly anchored to the bottom at a sufficient depth, so that it has no influence on the surface profile. The potential function φ is defined as the sum of the incident wave velocity potential φ w and the scattered wave velocity potential φa. The results of measurements of wave-induced pressures and forces on a horizontal cylinder located close to the bottom are compared with the theoretical solution based on the potential theory for incompressible, perfect fluid and ideal boundary conditions at the bottom and the surface of the cylinder. The experiments were carried out in the Large Wave Channel in Hannover with a cylinder of 0.8 m diameter. Thus the results are in a scale which corresponds to real pipelines. The analysis shows that the potential theory explains the components with double frequency of the wave in pressures and vertical forces as far as the amplitudes are concerned. In the experiments, the Keulegan-Carpenter number is rather low and the inertia hydrodynamic forces on the cylinder are dominant. It seems that the observed phase shift between the force component and the wave results from the energy dissipation which is not considered in the theoretical solution.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Modification of the Rigid Finite Element Method in Modeling Dynamics of Lines and Risers
Modyfikacja metody sztywnych elementów skończonych w modelowaniu dynamiki lin i riserów
Autorzy:: Adamiec-Wójcik, I.
Brzozowska, L.
Wojciech, S.
Tematy:: slender links
rigid finite element method
risers
hydrodynamic forces
internal flow; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/140334.pdf Link otwiera się w nowym oknie
Opis:: The paper presents an application of the modified rigid finite element method to analysis of the dynamics of slender structures. The equations of motion are formulated for a system discretized by means of the method, and discussion is limited to planar systems and large deformations. Slender elements can be found in offshore engineering as lines, cables and risers. In these cases the hydrostatic influence of water and sea currents has to be taken into account. While analyzing dynamics of risers it may also be necessary to consider the flow of fluid inside the riser. The influence of hydrodynamic coefficients and the velocity of the internal flow of fluid on displacements and forces is presented.
W pracy przedstawiono zastosowanie zmodyfikowanej metody elementów skończonych do analizy dynamiki wiotkich struktur. Sformułowano równania ruchu układu dyskretyzowanego prezentowaną metodą, przy ograniczeniu rozważań do płaskich układów i uwzględnieniu dużych ugięć. Elementy wiotkie spotykane są często w technice offshore’owej jako liny, kable i risery. Analizę dynamiki tych elementów trzeba jednak wówczas uzupełnić o hydrostatyczne oddziaływania wody i prądów morskich. W przypadku riserów, należy też uwzględnić możliwość przepływu płynu w ich wnętrzu. Na przykładzie risera pokazano wpływ współczynników hydrodynamicznych i prędkości przepływu płynu we wnętrzu risera na przemieszczenia i siły.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: Construction and analysis of mathematical models of hydrodynamic forces and moment on the ships hull using multivariate regression analysis
Autorzy:: Kryvyi, O.
Miyusov, M. V.
Tematy:: mathematical model
hydrodynamic forces
ship's hull
multivariate regression analysis
hydrodynamic moment
fisher's criteria
student's criteria
hydrodynamic characteristics; Pokaż więcej
Wydawca:: Uniwersytet Morski w Gdyni. Wydział Nawigacyjny
Powiązania:: https://bibliotekanauki.pl/articles/2063993.pdf Link otwiera się w nowym oknie
Opis:: To analyse the existing mathematical models of hydrodynamic forces and moment on the ship's hull and build new effective ones, an approach based on multivariate regression analysis is suggested. As factors (regressors), various dimensionless ratios of the geometric parameters of the vessel, such as length, breadth, draught, and block coefficient, were taken. When analysing existing mathematical models of hydrodynamic derivatives and building new ones, the value of the multiple correlation coefficient R and the value of standard errors were estimated. The significance of the models and the significance of all factors (regressors) included in the model were assessed using Fisher's and Student's criteria. As a result, new adequate mathematical models have been obtained for hydrodynamic constants with a high degree of correlation and an excellent level of significance of regressors.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: Approximate Method of Calculating Forces on Rudder During Ship Sailing on a Shipping Route
Autorzy:: Żelazny, K.
Tematy:: Ship Operation
Rudder
Hydrodynamics
Plane Rudder
Ship Design
Forces on Plane Rudder
Hydrodynamic Forces
Forces Calculation; Pokaż więcej
Wydawca:: Uniwersytet Morski w Gdyni. Wydział Nawigacyjny
Powiązania:: https://bibliotekanauki.pl/articles/116163.pdf Link otwiera się w nowym oknie
Opis:: Service speed of a ship in real weather conditions is a basic design parameter. Forecasting of this speed at preliminary design stage is made difficult by the lack of simple but at the same accurate models of forces acting upon a ship sailing on a preset shipping route. The article presents a model for calculating forces and moment on plane rudder, useful for forecasting of ship service speed at preliminary stages of ship design.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: Construction and analysis of new mathematical models of the operation of ship propellers in different maneuvering modes
Autorzy:: Kryvyi, O.
Miyusov, M. V.
Kryvyi, M.
Tematy:: ship propellers
curvilinear motion
mathematical models
hydrodynamic forces
hydrodynamic moments
wake fraction
thrust-deduction factor
drift angle; Pokaż więcej
Wydawca:: Uniwersytet Morski w Gdyni. Wydział Nawigacyjny
Powiązania:: https://bibliotekanauki.pl/articles/24201453.pdf Link otwiera się w nowym oknie
Opis:: The influence of the curvilinear movement of the ship on the operation of the propeller was studied. It is shown that even at small values of the drift angle and the angular velocity of the vessel, the transverse component of the force on the propeller and the moment are non-zero and cannot be neglected. The existing and proposed new effective mathematical models of the longitudinal and transverse components of force and moment caused by the operation of the ship's propeller are analyzed. Simple expressions for the coefficients of the propeller thrust and the moment on the propeller shaft, the wake fraction, the thrust-deduction factor, and the flow straightening factor on the propeller at any drift angles and angular velocity are obtained. Numerical analysis of the obtained dimensionless components of forces and moments caused by the operation of the propeller is carried out, and their adequacy is shown. It is shown how the specified parameters change for all possible values of the drift angle and angular velocity. For a few commercial vessels of various types, technical characteristics and calculated dynamic parameters are given for the construction of mathematical models of propeller operation during curvilinear movement of the vessel.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 8.

Tytuł:: Hydrodynamic forces on a submerged horizontal circular cylinder in uniform finite depth ice covered water
Autorzy:: Sahu, M.
Das, D.
Tematy:: fala powierzchniowa
elektrodynamika
dyfrakcja fal
wave scattering
hydrodynamic forces
submerged cylinder
ice-covered water; Pokaż więcej
Wydawca:: Uniwersytet Zielonogórski. Oficyna Wydawnicza
Powiązania:: https://bibliotekanauki.pl/articles/1839795.pdf Link otwiera się w nowym oknie
Opis:: Hydrodynamic forces on a submerged cylinder in uniform finite depth ice-covered water is formulated by using the method of multipoles, the ice-cover being modelled as an elastic plate of very small thickness. The forces (vertical and horizontal) are obtained analytically as well as numerically and depicted graphically for various values of flexural rigidity of the ice-cover to show the effect of its presence. When the flexural rigidity and surface density of the ice-cover are taken to be zero, then the curves for the forces almost coincide with the curves for the case of uniform finite depth water with free surface.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 9.

Tytuł:: CFD Based Hull Hydrodynamic Forces for Simulation of Ship Manoeuvres
Autorzy:: Tabaczek, T.
Gornicz, T.
Kulczyk, J.
Tematy:: Manoeuvring
Simulation of Ship Manoeuvres
Equations of Ship's Movement
Hydrodynamic Forces
CFD Computations
Hydrodynamic Characteristics
Ship's Motion
mathematical model; Pokaż więcej
Wydawca:: Uniwersytet Morski w Gdyni. Wydział Nawigacyjny
Powiązania:: https://bibliotekanauki.pl/articles/117623.pdf Link otwiera się w nowym oknie
Opis:: There have been developed numerous mathematical models describing the motion of a ship. In opinion of present authors the CFD is mature enough to determine with confidence the hydrodynamic characteristics necessary to simulate ship manoeuvres. In this paper the authors present the attempt to determine the hull hydrodynamic forces using the results of CFD computations of ship flow. Results show qualitative agreement with reference data and reveal shortcomings due to simplifying assumptions applied in CFD computations.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 10.

Tytuł:: Simulation in reduced scale hydraulic models of the mooring system of ships docked under the effect of the passage of other vessels (passing ship)
Autorzy:: Esferra, R.
Bernardino, J.C.M
Bezerra, R.
Pion, L.M.
Tematy:: passing Ship
hydraulic models
mooring system
passing ship phenomenon
ship's mooring
hydrodynamic interaction effect
hydrodynamic forces
reduced scale models; Pokaż więcej
Wydawca:: Uniwersytet Morski w Gdyni. Wydział Nawigacyjny
Powiązania:: https://bibliotekanauki.pl/articles/2063985.pdf Link otwiera się w nowym oknie
Opis:: Vessels moored at port terminals may be subject to excessive strain on mooring lines, induced by other ships passing in their vicinity. This phenomenon is called hydrodynamic interaction, and well known in the international literature as Passing Ship. It occurs due to the displacement of the mass of water between the two vessels, which, consequently, induces hydrodynamic stresses on the two ships. Within this context, scale models are a powerful tool for hydrodynamics studies, being able of reproduce the complex water flow phenomena that take place around passing and moored ship. This paper presents a scale model technique to study the Passing Ship phenomenon and its application on a case study developed for the Santos Port. The study was based on the analysis of the results of simulations performed on a 1:170 scale model to compare the effect of various navigations conditions on the mooring lines of a docked ship.
Dostawca treści:: Biblioteka Nauki

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