Sharif Digital Repository

In recent years, planing boats have been used in more exposed areas, for instance as patrol boats, pilot boats, coast guard and small naval vessels. When such a small vessel operating in a rough-water environment, frequently experiences violent motions and vertical acceleration. Even on calm water, porpoising may occur and may be severe as the speed is increased. Operation of the crew, equipments and overall operability of the vessel always suffer from mentioned motions. In the present study, the impact of fixed and controlled interceptors on a planing crafts hydrodynamic and seakeeping quality is investigated through application of an experimental and theoretical methods. Two scaled-down... 

The necessity of electrical energy, high cost of big power plants and high voltage transmission lines and also progressing of restructuring science has lead to the increasing of tendency to use the distributed generation in electrical industry. Among of different types of distributed generations, fuel cell power plants because of many advantages such as high efficiency, low emission, modular structure and ect., have a high potential to be used in power systems. The fuel cells produce electrical energy by chemical reactions. Due to the necessity of having the knowledge related to the chemical reaction which are effective on fuel cell, to study the fuel cell performance, this type of... 

With the increasing penetration of renewable energies as distributed generation (DG) in power systems, technical problems arise in both distribution and transmission system level. Voltage rise is the main barrier for connection of DGs in rural areas, while excessive reactive power demand from transmission system is the major concern for Transmission System Operators (TSO). Here, a centralized control scheme based on the Smart Grid is proposed to reduce the impact on the transmission system voltages and improve its stability, while mitigating the voltage rise issue in the distribution network. Reactive power output of DGs, substation capacitors and tap setting of transmission transformer are... 

Sea and ocean waves develop in various ways especially by blowing wind over them. Modeling of these waves has been in center of interest for half a century. After the pioneering study of Gelchi et al (1995), ocean wave models are generally base on a spectral energy or action balance equation. Ocean storms such as tropical cyclone will develop if the atmospheric and oceanic conditions are available. Their Rotational and transition movement causes different patterns of waves. In 2007, cyclone Gonu, a tropical cyclone that formed in Indian ocean and have steered to Oman Sea and also caused damages and casualties in southern coast of Iran. Since intense tropical cyclones such as Gonu have... 

This thesis consists of three main chapters. The first chapter is about describing principles about offshore wind turbine, principal concepts. This chapter also explains about advantages and disadvantages of installing wind turbine at offshore fields, and economical aspect of this kind of wind turbine farms. In the second chapter,anumerical method is used to investigate a SeaStar tension leg platform offshore wind turbine response behavior in parked condition. This code considers nonlinearities due to changes in tension of tethers. Wave forces are calculated adopting the Airy wave theory. Furthermore, shear turbulent wind is exerted on tower, with maximum speed 30 m/s on the hub. Since surge... 

Use of wind energy is always one of the aims of man during the times. He used this energy for wheat grinding and sometimes for marine transportations. During recent decades, technology development forced human to harness this energy and use that for electricity production by employing onshore wind turbines. However, the modern engineering employed different arms of engineering such as marine engineering, civil engineering, mechanical engineering and electrical engineering for designing and installation of offshore wind turbines. But, huge water depths in offshore regions make the fixed leg turbines to be unacceptable solution. So, the floating wind turbines with mooring lines which attach... 

The demand in water and energy for household, industrial and agricultural uses continue to grow. In recent years, many researches have been done on thermodynamic assessment and optimization of Combined Cooling, Heating and Power (CCHP) and desalination systems. The interesting and important point is the potential of combining CCHP and desalination systems by employing the solar power. The purpose of this study is exergy analysis and thermoeconomic optimization of a hybrid system of Multi-Effects Distillation desalination (MED) and CCHP, augmented by solar energy. The thermoeconomic analysis is carried out by Total Revenue Requirement (TRR) method. Properties of working fluid in hybrid MED... 

Based on codification and implementation of regulations of supporting from development of distributed generation sources, it is expected that in future years, investment in distributed generation scheme will be welcomed by private investors impressively. Under this circumstances, distribution Company will be faced with new chances for improving quality level of their services and optimal management of penalty-reward schemes. Penalty-reward schemes is set by legislator for distribution Company in order to improve their network. One of the pioneer ways is using distributed generators. So first, distribution Companies have to find optimum places for using these generators and in the second step... 

Today, to reduce the effects of greenhouse gases on the earth, as well as reduce dependence on fossil fuels and other non-renewable sources, the international community is moving towards greater use of renewable energy. The oscillating water column device as a wave energy converter system has the ability to use and absorb energy within the waves through a chamber consisting an air and a water column. This system has the ability to move the turbine installed on the valve by expanding and compressing the air passing through the valve. Oscillating water column systems have different categories, and this high diversity makes the choice of this wave energy converter closely related to the... 

With regards to rapid growth of world population, coastlines have limited natural resources and capacity for human settlement. To tackle the problem the idea of constructing artificial islands could be a solution. Since the artificial islands are semi-enclosed body of water designed to attract not only tourists but also settlements, the flow current pattern and residence time of water should be studied in detail in order to ensure adequate water quality in the surrounding area. In this study, an artificial island is planned to be constructed around Kish Island in Persia Gulf. In this article the effects of different geometries on circulation and residence time of water are investigated... 

Super cyclone GONU formed on June 2007 has been recognized the strongest tropical cyclone in the North Indian Ocean (NIO). The aim of this study is to numerically simulate the cyclone GONU and its resulting waves in the southern seas of Iran leading to the best parametric model to simulate future occurrence of tropical cyclones (TCs) in the NIO. In this regard, the best track data of the cyclone is extracted from Indian Meteorological Department (IMD). The cyclone GONU wind field is simulated by Young and Sobey, Holland, and Rankin models in order to determine the most appropriate model which is then considered for regenerating cyclonic wind fields over the Makran coastline and the sea of... 

One of the most significant challenges and issues that port engineers and coastal specialists face in the field of improving port performance is the design and development of hardware systems to enhance the efficiency of loading and unloading operations of ships. These systems need to be designed in a way that reduces the duration of loading and unloading operations of ships and improves the efficiency of cranes. One efficient technology in this field is the Automatic Mooring Systems, which are connected to the hull of berthed ships and use hydraulic cylinders to generate control forces. On the other hand, as evident in today's world, artificial intelligence is recognized as a vital and key... 

Limited fossil resources, daily increase of demand for energy and the most important one that is environmental pollution fact, make people think of renewable energy as a solution. One type of these renewable energies is offshore wind energy that has high potential without any sound and visual noises. Recently a lot of researches have carried out their studies on the topic of offshore wind turbine. Cause of disabling of a lot of software to simulating of dynamic effect of rotating rotors, so in this research has make effort to fabricate and test an offshore wind turbine with different rotor rotating velocities and different heading angle of wind, to catch the effect of these parameter on the... 

Many species in nature exist which human can reach the aims of flying and swimming by inspiring from them. Observations show that fish can use their especial undulating motions of body/fins to crusing, increase performance, suddenly acceleration, and maneuvering. To design a robot fish and benefit the characteristics and abilities of a live fish, using its real geometry and kinematics in the robot is vital. Therefore, simulations are essential to better exploiting the fish behavior, which can obtain useful consequences by using computational fluid dynamics. In this thesis, first the kinematics of sharks is investigated. Then, investigations are accomplished by utilizing an unsteady finite... 

With the increase of renewable energy generation in power systems, the flexibility of power systems has been challenged and the high potential of resources in active distribution systems for providing flexibility has been noticed by system operators and planners to help system flexibility. In this regard, these resources can participate in the Flexible Ramp Product market which is a new product that is defined for this purpose. In this work, the management of these resources has been modeled in an active distribution system for participating in this market by considering the network constraints, the uncertainty of renewable generation and forecasted prices of products in DA and RT markets,...