مهندسی دریا
Mohsen Shojaie; Mostafa Jafarzadeh Khatibani; Etemad ODin Rabei Gholami
Abstract
Estimating the required propulsive power of a vessel at early stage of design is important from two aspects, which are estimating the weight of the machinery as a function of required power and estimating the amount of fuel needed to determine the initial capacity of the vessel. This approximation can ...
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Estimating the required propulsive power of a vessel at early stage of design is important from two aspects, which are estimating the weight of the machinery as a function of required power and estimating the amount of fuel needed to determine the initial capacity of the vessel. This approximation can be based on empirical formulas, data of similar ships or diagrams deduced from statistical data for various types and sizes of ships. Current empirical formulas for estimating ship power are only limited to very few general equations and are inaccurate for specific type of vessels. In this study, by using 90 container ship data and multiple linear regression method, several statistical models were prepared and statistically analyzed considering the influence of the main parameters of the vessels on the required amount of power, and finally a suitable formula extracted. Evaluation of the extracted formula indicates acceptable accuracy for the container ships which can be used to estimate the required power of container ships within the range of this formula.
مهندسی دریا
Shahrzad Nikbakht; Ahmad Hajivand; Mostafa Jafarzadeh Khatibani
Abstract
Power requirements increase severely in rough weather because of added resistance induced by water wave. Amplitude of this additional resistance is between 15 to 30 percent of the ship calm water total resistance. Nowadays, one of the important issue in naval architect is to design a ship hull with minimum ...
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Power requirements increase severely in rough weather because of added resistance induced by water wave. Amplitude of this additional resistance is between 15 to 30 percent of the ship calm water total resistance. Nowadays, one of the important issue in naval architect is to design a ship hull with minimum added resistance that produce less greenhouse gas. There are several numerical viscous and non-viscous method like strip theory, panel method and RANS method. With respect to accuracy and cost calculations, 3-D panel method is the best choice for analysis ship behavior in wave. By using frequency domain Green's function 3-D panel method added resistance of S-175 containership is computed by far filed and near field approaches. To investigate the effect of wave incident and wavelength, calculations are performed in different incident angle and wavelength. Also by using an accurate and fast empirical validated method that have recently been proposed, added resistance in head sea are calculated for different wavelength and ship speed. Far field and near field results are consistent with good accuracy. Numerical and empirical results are compared with experimental that shows high accuracy results.