Wyniki wyszukiwania - BazTech

1

Construction and analysis of new mathematical models of the operation of ship propellers in different maneuvering modes

Kryvyi O., Miyusov M. V., Kryvyi M.

TransNav : International Journal on Marine Navigation and Safety of Sea Transportation

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2023

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Vol. 17 No. 1

95--102

EN

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.

2

Numerical prediction of propeller-hull interaction characteristics using RANS method

Tu Tran Ngoc, Luu Do Duc, Ha Nguyen Thi Hai, Quynh Nguyen Thi Thu, Vu Nguyen Minh

Polish Maritime Research

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2019

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nr 2

163--172

EN

The paper presents the results of computational evaluation of the hull-propeller interaction coefficients, also referred to propulsive coefficients, based on the unsteady RANS flow model. To obtain the propulsive coefficients, the ship resistance, the open-water characteristics of the propeller, and the flow past the hull with working propeller were computed. For numerical evaluation of propeller open-water characteristics, the rotating reference frame approach was used, while for self-propulsion simulation, the rigid body motion method was applied. The rotating propeller was modelled with the sliding mesh technique. The dynamic sinkage and trim of the vessel were considered. The free surface effects were included by employing the volume of fluid method (VOF) for multi-phase flows. The self-propulsion point was obtained by performing two runs at constant speed with different revolutions. The well-known Japan Bulk Carrier (JBC) test cases were used to verify and validate the accuracy of the case studies. The solver used in the study was the commercial package Star-CCM+ from SIEMENS.

3

Wybrane problemy wyznaczania wartości współczynnika strumienia nadążającego

Behrendt C.

Zeszyty Naukowe / Wyższa Szkoła Morska w Szczecinie

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2002

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nr 66

61-72

PL

Przedstawiono problemy wyznaczania wartości współczynnika strumienia nadążającego. Porównano jego wartości uzyskane w wyniku badań modelowych i z wykorzystaniem metod uproszczonych. Zaprezentowano także metodę wyznaczania współczynnika sprawności strumienia nadążającego, umożliwiającego porównanie strumieni nadążających dla różnych statków.

EN

The paper presents problems of wake fraction value determination. The calculation results of analytical simplified formulas have been compared with ship model test results. For the critical examination and the comparison of different wake fields, the method of wake efficiency number determination is also presented.