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EN
The paper contains the analysis of the possibility of container transportation on the Oder Waterway (the Gliwice Canal, the canalized stretch of the Oder River, and the regulated stretch of the Oder River), on the assumption that the waterway complies with conditions of class III European waterway. The analysis is based on the concept of modern motor cargo vessel, adjusted to hydraulic parameters of waterway. The vessel is designed for ballasting when passing under bridges. The amount of ballast water that enables transportation of two tiers of containers is given. The costs of waterborne transportation are compared to the costs of rail transportation of containers on selected shipping routes.
EN
Data from model tests of an inland waterway vessel in shallow water have been used by the authors to prepare the resistance prediction in full scale. The common ITTC-1978 extrapolation procedure was applied using form factor determined according to the Prohaska method and, separately, by fitting the approximation function to resistance data. At the same time a series of CFD computations of ship flow has been carried out in model scale and in full scale, with double-body model as well as including the effect of free surface. The results of computations were used to determine total resistance and form factor. The values of form factor determined using different methods are similar and relatively high in comparison to values being applied to conventional sea going ships. Resistance prediction according to the ITTC-1978 with form factor was compared to prediction without form factor. The relative difference of resistance amounts 28% at ship speed of 10 km/h and 24% at ship speed of 12 km/h.
EN
By using fully theoretical method the heeling moment due to centrifugal forces has been determined for a small river cruiser in turning manoeuvre. The authors applied CFD software for determination of hull hydrodynamic forces, and open water characteristics of ducted propeller for estimation of thrust of rudder-propellers. Numerical integration of equations of 3DOF motion was used for prediction of ship trajectory and time histories of velocities, forces and heeling moment.
4
Content available Drag and Torque on Locked Screw Propeller
EN
Few data on drag and torque on locked propeller towed in water are available in literature. Those data refer to propellers of specific geometry (number of blades, blade area, pitch and skew of blades). The estimation of drag and torque of an arbitrary propeller considered in analysis of ship resistance or propulsion is laborious. The authors collected and reviewed test data available in the literature. Based on collected data there were developed the empirical formulae for estimation of hydrodynamic drag and torque acting on locked screw propeller. Supplementary CFD computations were carried out in order to prove the applicability of the formulae to modern moderately skewed screw propellers.
EN
Propeller-hull interaction coefficients - the wake fraction and the thrust deduction factor - play significant role in design of propulsion system of a ship. In the case of inland waterway vessels the reliable method of predicting these coefficients in early design stage is missing. Based on the outcomes from model tests and from numerical computations the present authors show that it is difficult to determine uniquely the trends in change of wake fraction and thrust deduction factor resulting from the changes of hull form or operating conditions. Nowadays the resistance and propulsion model tests of inland waterway vessels are carried out rarely because of relatively high costs. On the other hand, the degree of development of computational methods enables’ to estimate the reliable values o interaction coefficients. The computations referred to in the present paper were carried out using the authors’ own software HPSDKS and the commercial software Ansys Fluent.
PL
Przedmiotem pracy jest numeryczna analiza trójwymiarowego przepływu cieczy rzeczywistej przez jednostopniową pompę odśrodkową z kierownicą spiralną w warunkach kawitacji. Obliczenia dla dwóch wirników były wykonywane programem FLUENT 6.3. Odtworzono i porównano z danymi doświadczalnymi charakterystykę przepływu pompy. Wyznaczono charakterystyki kawitacyjne dla wybranych wydajności pompy i na tej podstawie charakterystykę ssania.
EN
This article concerns the numerical analysis of 3-D cavitating flow of real fluid in the single-stage centrifugal pump with volute. Computations for two different impellers were carried out using the Ansys Fluent 6.3 software. Pump curve was reproduced and compared to empirical data. Head-drop curves were computed for selected flow rates and used to determine the net positive suction head (NPSH).
PL
W pracy porównano ze sobą wyniki analizy przepływu wykonane dwuwymiarową metodą osobliwości oraz trójwymiarową metodą rozwiązywania uśrednionych równań Naviera-Stokesa. W pierwszym przypadku obliczenia dotyczyły palisady samego wirnika omywanej cieczą doskonałą. W drugim przypadku dotyczyły całej pompy przy czym uwzględniono zarówno lepkość medium jak i niestacjonarność przepływu związaną z obrotami łopatek wirnika względem nieruchomego języka spirali. Odtworzono chakterystykę przepływu oraz rozkłady prędkości i ciśnień. Sformułowano wnioski.
EN
In his paper there are compared the results off flow analysis made using the 2-D method of singularities and the 3-D method based on solution of RANSE. In thefirst case there was calculated theflow of inviscid fluid through the cascade of impeller blades. In the second case there was computed the flow of viscous fluid through the entire pump, including the unsteadiness of jjfem i ftused by rotation of impeller in relation to non-symmetric volute casing. Flow characteristics and distributions of velocity and pressure were predicted. Conclusions were formulated.
EN
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.
9
Content available remote Computation of flow around inland waterway vessel in shallow water
EN
Flow around an inland waterway vessel in shallow water was computed in model scale using CFD software Fluent. Theoretical data were compared to the results of measurements in towing tank. The comparison comprises ship resistance, wave profile on hull surface, and distribution of velocity in tlow around bow and stern.
PL
Przy użyciu programu komputerowego Fluent obliczany był przepływ wokół kadłuba statku śródlądowego w skali modelu. Wyniki obliczeń zostały porównane z wynikami pomiarów w basenie holowniczym. Porównanie obejmuje opór kadłuba, profil fali na powierzchni kadłuba i rozkład prędkości przepływu w pobliżu dziobu i rufy.
EN
These authors performed a set of numerical calculations of water flow around pushed barges differing to each other by bow forms. The calculations were executed by means of FLUENT computer software. Turbulent free-surface flow of viscous liquid was considered. In this paper the calculated values of barge hull resistance split into bow, cylindrical and stern part components, have been compared and presented.
11
Content available remote Zastosowanie metody panelowej do analizy hydrodynamicznej śruby okrętowej
PL
Autorzy zastosowali metodę panelową z powierzchniowym rozkładem wirowości do modelowania przepływu potencjalnego wokół śruby okrętowej. Powierzchnia skrzydła i piasty została zastąpiona panelami z wirowością. Ślad hydromechaniczny za skrzydłem modelowany był przy pomocy włókien wirowych o kształcie linii śrubowej. Wpływ lepkości został uwzględniony w sposób przybliżony, przez zastosowanie empirycznych współczynników oporu profilu. Model przeznaczony jest do analizy hydrodynamicznej śrub okrętowych pracujących w obwodowo niejednorodnym polu prędkości. Umożliwia obliczanie sił hydrodynamicznych działających na skrzydła i momentu na wale śrubowym, oraz rozkładu ciśnienia na powierzchni skrzydeł.
EN
In the paper the mathematical model of hydraulic system with accumulator was presented. The model was based on electrical analogy for laminar flow in second phase hydraulic cylinder starting. Calculations were done and diagrams were prepared: flow rate, pressure in accumulator and in hydraulic cylinder and piston stroke.
EN
Model tests of propeller performance in bollard conditions, in deep and shallow water, were carried out at Ship Design and Research Centre in Gdansk. Corresponding calculations of propeller performance with account for finite dimensions of canal cross-section were carried out at Wroclaw University of Technology by using their own theoretical model of propeller -hull interaction. The calculations were carried out in model scale, at the same water depth as in model tests. For given hull form, propeller geometry and canal cross-section the HPSDK computer code was used to calculate wake fraction, as well as propeller thrust, torque and efficiency. The distribution of pressure on waterway bottom and ship sinkage were also determined.
EN
In the present paper presented is a method of determining the speed prediction using numerical methods. Computer code HPSDK is a base of this method. For given hull form and limits of waterway the code allows to calculate the performance of screw propeller. The applied theoretical model accounts for hydrodynamic interaction between propeller, ship hull and the boundaries of waterway. In combination with the curve of thrust demand it is possible to determine the speed prediction for wide range of operation parameters. Some results of computations in comparison with model test data are presented as an example.
PL
W referacie przedstawiono metodę określenia prognozy napędowej z wykorzystaniem metod numerycznych. Podstawą jest system obliczeniowy HPSDK. Umożliwia on dla zadanego kształtu statku i znanych ograniczeń drogi wodnej określić parametry pracy pędników śrubowych. Model obliczeniowy uwzględnia wzajemne oddziaływanie pędnika, kadłuba statku i drogi wodnej. W połączeniu z znaną krzywą zapotrzebowania naporu stwarza to możliwość określenia prognozy napędowej dla szerokiego zakresu zmiany parametrów eksploatacyjnych. Przedstawiono przykładowe wyniki obliczeń dla zestawu pchanego wraz z porównaniem z wynikami badań modelowych.
PL
Autorzy przedstawili teoretyczne podstawy metody powierzchniowego rozkładu wirowości i zapis równań w krzywoliniowym, nieortogonalnym układzie współrzędnych. Metoda została zastosowana do obliczania przepływu potencjalnego wokół płata nośnego o małej rozpiętości i zaokrąglonych wierzchołkach. Przedstawiono wyniki obliczeń rozkładu ciśnienia i kierunku przepływu na powierzchni płata
EN
The authors present theoretical basis of surface vorticity distribution method and equations written in curvilinear, non-orthogonal co-ordinates. The method was applied to calculation of potential lifting flow around airfoil of low aspect ratio and rounded tips. Computed pressure distribution and flow direction on the surface of airfoil are presented.
15
Content available remote Theoretical investigation of the wake duct effectiveness
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.
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