مهندسی دریا
Mousa Damavandi; Rouzbeh Shafaghat; Morteza Dardel
Abstract
Anti-Rolling Gyro (ARG) is one of the useful equipment which is used for enhancing stability of vessels. ARG produces a moment against wave torque and reduces undesirable vessel roll based on gyroscopic concepts and using flywheel moment. The first step in designing ARG is flywheel design which exerts ...
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Anti-Rolling Gyro (ARG) is one of the useful equipment which is used for enhancing stability of vessels. ARG produces a moment against wave torque and reduces undesirable vessel roll based on gyroscopic concepts and using flywheel moment. The first step in designing ARG is flywheel design which exerts appropriate moment in order to reduce rolling of vessel with attention to the sea wave moments and angular velocity of the waves. According to direct relation of righting moment of gyro with mass moment inertia, in order to increase righting moment, it should be chosen a flywheel with high moment inertia, in the contrary, increasing moment inertia also leads to increasing mass of flywheel. In this study, with regards to conditions of waves of Persian Gulf, for optimizing of mass and moment inertia, non-dominated sorting multi objective genetic algorithm (NAGA-II) is used, in a way that minimum mass and maximum moment inertia will be gained. Finally, the dimension of all the flywheel optimal options are demonstrated in the form of pareto diagram, in order that performance conditions regarding parameters including mass and the number of gyros in a vessel based on gained results, are being investigated.
مهندسی دریا
Negin Donyavizadeh; Rouzbeh Shafaghat; Morteza Dardel; Saeid Mohammadzade Negharchi
Abstract
High speed craft with the wide and various uses of entertainment, sporting, commercial and military, usually has a top speed of 30 knots. Due to the limitations of the design, use of propulsion system is a key issue, with regard to the desirable features surface-piercing propeller, their use in the propulsion ...
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High speed craft with the wide and various uses of entertainment, sporting, commercial and military, usually has a top speed of 30 knots. Due to the limitations of the design, use of propulsion system is a key issue, with regard to the desirable features surface-piercing propeller, their use in the propulsion system of the vessel, has been very useful. High efficiency, no restrictions to increase the diameter, resistance equipment supplied propeller removed, the proper functioning of cavitation, are examples of these features. To achieve the best efficiency and thrust requirements, requires accurate determination of the coefficient of hydrodynamic thrust and torque. Given the importance of determining the coefficients and their dependence on various physical parameters and geometric, it is necessary to understand the effect of these parameters on the hydrodynamic coefficients, so in this study, experimental tests and collect data using sensitivity analysis, the weight of each parameter and the interaction of parameters ُsurface-piercing propeller to evaluate the hydrodynamic coefficients on the propeller thrust, propeller torque, and therefore performance, is desired. Based on the results obtained, the parameters of step angle, ُskew and compared to other parameters, have the greatest impact in changing the propeller efficiency, while changing the ratio Immersion, the change will have little impact on efficiency and propeller.