Sharif Digital Repository

The growing requirements for renewable energy production lead to the development of a new series of systems, including wave and tidal energy conversion systems. Due to their sensitivity and the impact of the aggressive marine environment, the selection of the most adequate location for these systems is a major and very important task. Several factors, such as technological limitations, environmental conditions, administrative and logistic conditions, have to be taken into account in order to support the decision for best location. The aim of the present study is to provide an Atlas of IRAN Offshore Renewable Energy Resources (hereafter called ‘the Atlas’) to map out wave and tidal resources... 

One of the utmost important factors during salvage operation of drowned ships is raising velocity. Uncontrolled raise is a dynamic phenomenon which can lead to the sudden tensions, collapse in airbags or ships. Studing this issue helps the engineers which kinds of problems are more important during salvage operations. This study focus on modeling and analysis of raising movment of the ship with FLOW-3D and ABAQUS software.
In FLOW-3D environment, hydrodynamic analysis of rising movment of drowned ship has been done. We should mention that applied forces and velocities and other parameters from the FLOW-3D output should be passed IMCA Criteria to avoid uncontrollable raise. In ABAQUS... 

Two experimental models were designed and tested to extract energy from vortex induced vibrations of a elastically mounted one degree of freedom rigid cylinder in the Reynolds range of 120000 < Re <220000. In the first model the amplitude and frequency of the movement was measured then a second model was designed to be tested in the Emam Hossein marine laboratory. The model was designed in a way that many of its properties like mass ratio, spring constant and damping coefficient were able to be altered. In this study the vortex induced vibration of an elastically mounted cylinder was scrutinized in high Reynolds and very low mass ratios for the first time and an amplitude ratio of 2.49 were... 

Marine current power has been utilized in recent years as one of the most foreseeable renewable energy sources. In this study a multi-objective hydrofoil optimal design is carried out for use in marine current turbine in order to improve hydrodynamic performance due to low speed current in Qeshm channel. A particle swarm optimization code using FORTRAN is developed and coupled with XFoil software as flow solver that is based on panel method. B-spline curve is used to parameterize the hydrofoil shape and the coordinates values of the control points are designated to act as optimization parameters. Validity of flow solver examined by comparison made between computed data against experimental... 

Darrieus turbines are one of the most widely used turbines in extracting energy from tidal currents. This study aimed to investigate the effect of utilizing helical blades and variable solidity ratio on the efficiency of Darrieus tidal turbines. For this purpose, three types of helical turbines with different solidity ratios have been designed, and computer simulation has been used to investigate the effect of the mentioned parameters on the efficiency of the Darrieus turbines. According to the simulation results, the helical turbine has less efficiency than the straight blade Darrieus turbine. The maximum hydrodynamic efficiency of the Darrieus turbine with straighted blades is 38.5,... 

The idea of using under water vehicles inspired by nature has gained considerable attention during the past few decades. This interest is due to the advantages of swimming and moving by this technique, in comparison with the conventional methods. Benefits are such as increasing speed, improved power, better manoeuvre ability,greater stability, optimal hydrodynamic performance ... etc. The purpose of this study was developing a model to simulate a stingray Manta Ray moving behaviour. Ansys- Fluent software was applied to solve the related equations of viscous laminar flow in 3-D form.Simulation of Manta Ray was performed with the flapping pectoral fin with dynamic mesh. Using this... 

Nowadays, because high global demand for energy has led to the extensive use of fossil fuels with numerous unintended consequences such as air pollution and greenhouse effect, research and development around optimization of energy infrastructure has become much more important. Consequently, many scientific approaches have been applied to replace fossil fuels with renewable natural energy resources. One of the renewable energy types that fewer papers have been published about it, is the enormous energy of Marine currents. The origin of this energy is mostly tidal effect, or ocean currents that are available in most of oceans and seas around the planet earth. The most important criteria for... 

The thesis title is “Modeling of a vague problem (Floating Breakwater by BEM Analysed) using ANFIS (Adaptive Neuro-Fuzzy Inference System) and validation by Fuzzy Boundary Element Method”. In this set of material, more important definitions are described below. When some input data is linguistics, or we have lack of Information or Vagueness, Fuzzy toolbox can alleviate the problem. Fuzzy concept includes several fields and applications like; fuzzy logic, fuzzy sets, fuzzy control, fuzzy arithmetic and fuzzy inference, and the last two applications are used in this thesis. The Neural network is a black box, Neurons that can justify their actions and these artificial brains can grow. The... 

Human have been thinking to discover all secrets of world, from long time ago. And also the sea exploring and using its resources, including oil and utilization of fish as feed have been the main causes of human interest to ocean. So to access these resources, constructed some equipment to be able to go under water, such as ROV and AUV.
Since the human is concluded that further facts need to synchronize to the world with the natural laws of nature in this area is the best model and teacher; new branch of science called bionic is exploded. For example, look and study of birds in the air movement have produced the fastest aircraft. Same knowledge in the field of marine sciences has... 

In the recent decades, because of the reduction of the fossil sources and increasing the environmental pollution, also worldwide population growth and the necessity of energy have made humanbeing to use the Renewable Energy. Wave energy is an opulent source of energy in many parts of the world, especially in Iran.
In this thesis, in the first chapter, different kinds of renewable energy are introduced, and the importance of them is discussed. In the second chapter, the mechanisms of extracting energy by the wave energy converters are investigated, and their types are discussed. Then, in the next chapter, wave equations, wave spctrums and simulation of a flap wave energy converter in... 

Tsunami, like many other natural disasters leaves people a short time for escape. When talking about Tsunami, the escape time is the period it takes for the wave to start moving from the epicenter, change into a giant wave gradually and reach to a cost. In order to minimize damages of this phenomenon, the escaped time has to be estimated without delay. For this purpose the first needed action is modeling the Tsunami waves. Analytical and numerical models and software that are designed based on them do exist. To have an efficient and rapid Tsunami alarming system all of these options are examined in this project. Then having a reliable model quite a few probable scenarios are propounded. The... 

In this work, we use computational fluid dynamic simulation tools for investigation two dimensional of eel movement. Firstly, the numerical study of smooth particle hydrodynamics was applied for determination drag coefficient and lift coefficient of undulation movement eel body. The initial mesh was manual. So, the effective parameters of eel movement were investigated. The smooth particle hydrodynamic method was not use, because of saving on time. Therefore, fluent software was used. UDF were added to the fluent software, which it can be move the boundary layer of mesh with eel movement. The dynamic mesh tools of fluent software were used. Initial shape had a curvature and utilized for... 

For more than a million years, aquatic animals and specially fishes make undulatory motions in their flexible body to propel themselves. In the recent decays, scientists prove that these mechanisms are more efficient than man-made propulsion systems. A wide variety of artificial vehicles including robotfishes, ROV and etc has been manufactured with inspiring by natural creatures. The Biomimetic science which deals with the study of mechanics and hydrodynamics of living creatures is very important in developing these vehicles. In the present study, numerical software (PANEL3D®), bases on boundary integral equations of potential flow have been developed to simulate hydrodynamic performance of... 

Analysis of hydrodynamic model of sea wave problems has very good conformity with boundary element method (BEM). Because, the governing equation of many sea wave problems is potential equation which is the base of BEM. In this research, after some explanation about BEM and its application in fluid mechanics, a new composition of elements on the discretized boundary is introduced in favor of increasing the precision. In this method, the constant elements are used in corner elements and the linear elements are used in other elements. This issue is validated by comparing with analytical solution. In addition, free surface flow with porous medium in the fluid is investigated in sloshing 2D... 

As it is obvious from the name of this study, the goal of doing this study is the feasibility study of southern shores of Iran for building an artificial energy island for and designing it. In this project by studying seven points coastwise of southern Iran and defining the criterions and scoring the points, the Chabahar was determined as the best place for erecting the artificial energy island. With respect to the environmental condition of the chosen point and modeling in software ANSYS, the structure of the artificial energy island has been studied and the type, geometric shape, area, trough, and the setting of the anchoring system has determined. As a result of these efforts, a hexagon... 

Today, the increase in greenhouse gases and the accumulation of thesegases in the atmosphere has caused a destructive environmental impact. Transportation systems in the country consume 25 % of the energy, which isalso the main cause of air pollution in addition to the imposition of fuelconsumption and fuel imports this has led to the design and deployment of vehicles with new technologies, necessity and importance that hybridvehicles is one of the new technologies. Considering that the average speedin road traffic is low and internal combustion engines have lower efficiencyand higher emissions, the hybrid vehicle reduces the current costs (fuelconsumption) and external costs (air pollution)... 

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... 

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... 

Pelamis is a semi-submersible device that can extract wave energy and converters that to electrical power. It has 5 cylindrical structure that connects through the joints. This device takes the shape of wave and the wave forces tubes to had angular relative motion together. The Main task of this device is to convert the angular movements of tubes to the Linear movement of pistons. External mechanism called the energy capture device are responsible for absorbing wave energy through angular movements, and then the internal mechanism, called the Power Take-Off, are responsible for converting this energy into the electrical power for use in the electricity grid. This device was designed and... 

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...