Wyniki wyszukiwania - BazTech

1

Experimental evaluation of forward speed effect on maneuvering hydrodynamic derivatives of a planing hull

Kazerooni M. F., Seif M. S.

Zeszyty Naukowe Akademii Morskiej w Szczecinie

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2017

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nr 49 (121)

40--53

EN

The calculation of unknown hydrodynamic derivatives of the equations of motion is the first step to estimate ship maneuverability and dynamic stability. These derivatives can be obtained theoretically, experimentally and numerically. Despite the development of the oblique towing model test to measure the hydrodynamic derivatives of displacement ships, limited experimental results are available for hydrodynamic derivatives of high speed crafts and speed dependency of the hydrodynamic derivatives is not understood well. In this paper a systematic series of model tests is described to determine the effect of forward speed on hydrodynamic derivatives of a monohull planing craft and the variations of the hydrodynamic derivatives by forward speed are derived. According to the results, hydrodynamic derivatives of planing hull are dramatically changed by variations of forward speed. Moreover, it is not possible to introduce a constant hydrodynamic derivative in the all the ranges of drift angle. Thus, the method of known constant hydrodynamic derivatives is not applicable to the simulation of planing craft maneuvering and variable hydrodynamic derivatives should be applied.

2

Bezpieczeństwo zbiornikowców LNG manewrujących na akwenach ograniczonych

Adamkiewicz A., Anczykowska A.

Systemy Wspomagania w Inżynierii Produkcji

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2017

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Vol. 6, iss. 7

11--20

PL

W artykule przedstawiono stan floty zbiornikowców LNG przewidywanych do obsługi terminala LNG, w tym z uwzględnieniem autoryzacji gazowca dla zapewnienia bezpieczeństwa żeglugi na obszarach ograniczonych. Rozpoznano przesłanki zagrożenia bezpieczeństwa statku na ograniczonej drodze wodnej, właściwości żeglugi zbiornikowców na akwenie terminalu oraz wpływ rodzaju głównego układu napędowego na cechy funkcjonalne gazowca. Na takim tle zdefiniowano wskaźniki bezpieczeństwa eksploatacji zbiornikowców jako narzędzi do oceny rodzaju napędu statku w aspekcie bezpiecznego wykonania zadania transportowego.

EN

The paper presents status of the LNG carrier fleet envisaged for serving an LNG terminal and it includes LNG carrier authorization to ensure sailing safety in restricted areas. It studies potential safety risks for ships in a restricted waterway, characteristics of LNG carrier sailing in terminal water areas and the influence of the main power system type on functional properties of an LNG carrier. With that background safety indicators for safe LNG tanker operation have been defined as a tool to evaluate the type of ship power system in the aspect of its safe transportation task performance.

3

Interaction of ships moving in opposing directions among ice floes

Goncharov V., Klementieva N., Zueva E.

Zeszyty Naukowe Akademii Morskiej w Szczecinie

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2015

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nr 43 (115)

91--98

EN

During winter in arctic seas, navigation of ships near ports occurs within ice channels created and maintained by icebreakers. Small ice floes fill the relatively narrow navigable channel, and ships are forced to produce the overtaking or opposing separation over short distances and under the action of ice floes. This paper presents an analytical model of the interaction of ships under the conditions just described as well as the results of a simulation. The simulation showed side force and yawing moments were dependent on ice conditions and the ship’s dimensions and motion characteristics.

4

Hydrodynamic Analysis of Trimaran Vessels

Javanmardi M. R., Jahanbakhsh E., Seif M. S., Sayyaadi H.

Polish Maritime Research

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2008

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nr 1

11-18

EN

Trimaran vessels are developed for different applications and hydrodynamic behavior of such vessels is different than usual mono-hulls. In this paper hydrodynamic resistance and maneuvering of a trimaran with Wigley body form are investigated. The effects of outriggers position in four different longitudinal and two transverse locations are studied. For hydrodynamic simulations a CFD code has been developed and used. This code is capable for simulating three dimensional, time dependent, two phases, viscous flow coupled with rigid body motion. Formulation and solution algorithm are described in detail. Different case studies have been performance and numerical results have shown good agreement with experimental data. Based on resistance and maneuvering simulation of the trimaran vessels different conclusion are made. The results show that positions of outriggers have great effect on resistance and maneuverability of trimaran. The present method can be further employed to investigate other hydrodynamic qualities of trimaran vessels.

5

Numerical Wake Assessment of Maneuvering Ship

Abramowski T.

Zeszyty Naukowe / Akademia Morska w Szczecinie

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2004

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nr 2 (74)

21-31

EN

The article presents an attempt at numerical wake determination of a ship moving with drift. For the calculation of viscous flow a numerical method based on the solving of RANS equations has been applied. A bulk carrier hull has been chosen for the analysis. The results show complex features of the flow in the stern area. Distributions of wake factor are strongly non-uniform both in radial and circumferential directions and the non-uniformity gets stronger as drift angle increases.

PL

Zaprezentowano próbę numerycznej oceny strumienia nadążającego statku poruszającego się z dryfem. Obliczenia opływu lepkiego wykonano metodą opartą na rozwiązaniu równań RANS. Do analizy wybrano kadłub masowca. Obliczenia wskazują na skomplikowane parametry przepływu w rejonie rufy. Rozkłady współczynników strumienia nadążającego są silnie niejednorodne tak promieniowo, jak i obwodowo i niejednorodność ta wzrasta wraz ze wzrostem kąta dryfu.