مهندسی دریا
kazem sadati; hamid zeratgar
Abstract
In past few years two-dimensional theories in numerical, analytical and experimental solution have contributed in seakeeping and maneuverability of vessels specially planing crafts. Analysis of wedge water entry as a basic problem has wide application. Till now much research in different methods has ...
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In past few years two-dimensional theories in numerical, analytical and experimental solution have contributed in seakeeping and maneuverability of vessels specially planing crafts. Analysis of wedge water entry as a basic problem has wide application. Till now much research in different methods has been done on the symmetric and asymmetric of wedge water entry. in this study wedge water entry with transverse velocity (or oblique water entry) will be studied. Model testing is a powerful means to deal with the said problem, in this study oblique water entry of wedge has been conducted. In this regard for oblique water entry of wedge a setup has been designed and fabricated. using by the fabricated setup a set of oblique water entry tests on wedge of 40 degree deadrise angle in different vertical and transverse velocity are examined and the pressure distribution on the plates of wedge due to impact of water are recorded. The results are illustrated the importance of transverse velocity on the pressure distribution and magnitude of vertical and transverse forces on the wedge. The pressure distribution due to oblique water entry on left and right side of the wedge are not symmetry; owing to increasing of transverse velocity the difference pressure on two sides of wedge is increased, so the transverse force is increased and the vertical force is decreased.
مهندسی دریا
AliAsghar Moghaddas Ahangari; Hamid zeraatgar; seyed khalil shariati
Abstract
In designing of a marine vehicle, derivation of hydrodynamic coefficients of the equations of motion is very important. For derivation of these hydrodynamic coefficient's various methods such as analytical-experimental methods, Computational Fluid Dynamic (CFD) method and model test can be used. Among ...
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In designing of a marine vehicle, derivation of hydrodynamic coefficients of the equations of motion is very important. For derivation of these hydrodynamic coefficient's various methods such as analytical-experimental methods, Computational Fluid Dynamic (CFD) method and model test can be used. Among These methods, due to the limitations of analytical-experimental methods and computational fluid dynamic method, the most accurate method is model testing.Empirically derived coefficients, which obtain in the marine laboratory, use to simulate the behavior of a marine vessel in the International Maritime Organization (IMO) maneuver test and determine the vessel's maneuverability.Due to differences in the marine laboratory equipment and test methods and to ensure the accuracy of results, standard models are tested and the results are compared against the results provided by the International Towing Tank Conference (ITTC).Accordingly, this article describes the process of model testing and derivation of the coefficients for the Esso Osaka benchmark vessel, using static and dynamic testing with Horizontal Planar Motion Mechanism (HPMM) in Shohada-e-Khalij-e-Fars national marine laboratory and compare the results with the results provided by the international towing tank conference.