مهندسی دریا
MORTEZA BAKHTIARI; AMIR ASHTARILARKI; Samer adnan
Abstract
Estimation of sediment transportation is one of the significant factors in river engineering. This is especially important in rivers that are used and exploited in many ways. The problem of sediment transport itself has some complexities and will be much more complex in tidal rivers. In the present study ...
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Estimation of sediment transportation is one of the significant factors in river engineering. This is especially important in rivers that are used and exploited in many ways. The problem of sediment transport itself has some complexities and will be much more complex in tidal rivers. In the present study using MIKE 21 model, particle velocity fall, erosion and sedimentation critical shear stress, Transition parameter between layers, Vertical diffusion coefficient and Roughness of bed stream are investigated. The results showed that particle velocity fall and sedimentation critical shear stress has no significant effect on sediment transport and the slope of the suspended load changes at different speeds is approximately the same. The results also show that by increasing the coefficient of transfer between layers, the concentration of suspended charge increases slightly.
مهندسی دریا
m b; m b; Nassim Ale Ali; m s
Abstract
Nowadays demand for renewable and reliable energy sources due to the global warming, environment pollution and global energy crisis is of utmost importance in offshore engineering. As a result of recent developments in wind industries extracting energy from offshore wind resources has a growth. A number ...
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Nowadays demand for renewable and reliable energy sources due to the global warming, environment pollution and global energy crisis is of utmost importance in offshore engineering. As a result of recent developments in wind industries extracting energy from offshore wind resources has a growth. A number of researches are carried out in the field of land based wind turbines but investigations about floating wind turbines as a consequent of their dynamic behavior complexity are still limited and further more detailed surveys are required. This paper presents an open source and public simulation code for the analysis and design of floating offshore wind turbines. The dynamic behavior due to environmental and inertial loads is obtained using a fully coupled comprehensive numerical tool implemented in MATLAB. blade element momentum theory used to determination of aerodynamic loads on wind turbine as well as Panel method and Morison's equation to calculate the hydrodynamic loads considering the instantaneous position of wind turbine system. The results show the domination of aerodynamic loads on wind turbine dynamic behavior as well as stability of structure due to the great difference between values of dominate aerodynamic excitation frequency and system natural frequencies.
مهندسی دریا
Morteza Bakhtiari; Ehsan Kamal pour asl; Javad Ahadiyan
Abstract
There is a different method for increasing the resistance and quality of engineering of soils, one of the most suitable ones is dynamic compaction. In this method, weights are released from the specified height and, as a result of collision with the ground, the soil will be compacted. In this research, ...
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There is a different method for increasing the resistance and quality of engineering of soils, one of the most suitable ones is dynamic compaction. In this method, weights are released from the specified height and, as a result of collision with the ground, the soil will be compacted. In this research, field experiments were initially initiated. Then using the results obtained in this section, the soil dynamic compaction was modeled. In order to do the modeling, the present study was conducted using FLAC two-dimensional software. Due to the implementation of various designs in the city of Abadan, the area was selected as the site of the project After field experiments, mechanical properties of the soil were extracted and then modeled with the definition of test patterns. The result of this research show that For all conditions of modeling, the maximum deformation of soil was observed in the hammer Cutoff area, which decreased in depth of soil. Also, the results indicate that effective stress in soil under dynamic density decreases with increasing depth.
مهندسی دریا
Morteza Bakhtiari; Shahriyar Shemshaki; Masoud Sadri nasab
Abstract
With the advent of technology and the expansion of human needs, the use of water platforms such as seas, oceans, and the recognition of methods and solutions for the design and implementation of marine structures is becoming increasingly clear.The semi-submerged platform is one of a variety of submarine ...
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With the advent of technology and the expansion of human needs, the use of water platforms such as seas, oceans, and the recognition of methods and solutions for the design and implementation of marine structures is becoming increasingly clear.The semi-submerged platform is one of a variety of submarine platform platforms, which, according to the features of the platform, is mainly used for extracting deep-sea oil and gas resources. In this research a semi- submersible platform under performance condition using ANSYS finite element software is numerical modeling and It is under regular waves. The platform's geometry is based on a platform built in 2012, and the data used in this study is about the average 20 years of Caspian waves.The degree of displacement, rotation, and force of diffusion has been obtained in degrees of freedom and are compared with each other. to apply regular waves Airy theory has been used. The result of this study show that In the loading of regular waves, the two parameters of the wave period and the wave propagation angle were the determining factor in the displacement and the platform time, as well as the dispersion force resulting from the collision of the wave with the platform. Also, the results show that at a 90 degree angle of the wave with the platform, the motion state at 2 degrees Z, Ry was close to zero and was the largest amount of time around the X axis.
مهندسی دریا
morteza Bakhtiari; FARZAD ORAK
Abstract
Sea Walls are constructed to protect coastal against of waves and prevent water to coastal. In order to properly understand the behavior of these structures must have proper information of loads to the structure. One of the main significance loads over the seawall is wave’s loads. Weight forces ...
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Sea Walls are constructed to protect coastal against of waves and prevent water to coastal. In order to properly understand the behavior of these structures must have proper information of loads to the structure. One of the main significance loads over the seawall is wave’s loads. Weight forces the walls, Weight backfill, Seawater weight on the heel wall and Forces exerted on the beach other forces that enters the coastal wall. Considering the importance of seawalls study on the stability of these structures has been the subject of study. In order to achieve the objectives of the study, three scenarios include changes in the geometry of the wall and Soil properties. In present study four geometry vertical, inclined, convex, concave, are considered and modeling with Flac 3D software. The results of this study showed that the minimum of horizontal and vertical displacement are about convex seawalls and the maximum of them is about vertical concave seawalls. Also the results showed that in the higher shear strength of soils the minimum of horizontal and vertical displacements occurred.
مهندسی دریا
Morteza Bakhtiari; seyed mahmood kashefipour; Mehdi GHomeshi
Abstract
One application of spur dikes is ensure navigability of rivers Through regulation and stabilization of sufficient width and depth, balance changes for the development of depth and The radius of curvature.Nowadays, spurs are also employed for promoting environmental conditions along a riverbank. One of ...
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One application of spur dikes is ensure navigability of rivers Through regulation and stabilization of sufficient width and depth, balance changes for the development of depth and The radius of curvature.Nowadays, spurs are also employed for promoting environmental conditions along a riverbank. One of the important topics abut spurs is their protection against scouring that has been less studied. One of the simple and economic ways for protection of spur against scouring is using riprap. Riprap is very common because it is easily available, cheap and simple for construction.Since using, spur dikes to protect riverbanks spatially in bends is very common, This research was carried out in order to investigate the effect of the structure stability. The purpose of this study is evaluation of depth-placed riprap for protection of spur dike in 90° Bend. In order to achieve the research objectives, one riprap size of inch diameter was used. Ripraps are placed in 3 depths ( ), and used for 3 lengths of spur(15%,20% and 25% width of flume), two angles (90 and 120 degree) and three longitude distance (3,5 and 7 times of spur length). Parameters as variables in this study were selected which The results can be used in large rivers, including navigable rivers and the Gulf.The results showed that stability of ripraps are increased with increasing the depth-placed riprap and angle of spurs, whereas increasing in spur length and longitude distance decreases stability of ripraps.
مهندسی دریا
Mahpeykar, Omid; Masoud Sadrinasab; , Morteza Bakhtiari; , Nima Shahni karamzadeh
Abstract
Developed countries are using renewable energy in order to minimize emission of harmful gases, and many countries are studied new designs. Which uses of the later is increasing rapidly. One of the cleanest renewable ocean energy is using the potential of tidal energy. Studies show that the best place ...
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Developed countries are using renewable energy in order to minimize emission of harmful gases, and many countries are studied new designs. Which uses of the later is increasing rapidly. One of the cleanest renewable ocean energy is using the potential of tidal energy. Studies show that the best place for obtaining tidal energy in the Persian Gulf and is the Doragh Estuary, which is located in the northern part of the Persian Gulf. This estuary is the unique area in the Persian Gulf with more than 5 meters tidal range which has the potential to produces maximum tidal energy in this region.In this study, a physical model of Doragh estuary is constructed and employed a pumping system as well as a source of water to create tide in the model. Also two dams are made somehow in the model to reserve water behind these dams during ebb and flood. A propeller which is connected to a turbine is fixed to one of the dams, and works during both ebb and flood in which transfers movement of propeller into electricity. Electrical current is connected to an instrument which show the amount of produced electricity in the model. The results of the model show that by increasing tidal range, electricity increases electricity exponentially. In this experiment the model run with different scenarios to get maximum efficiency which is recorded to 15% during flood and producing of electrical power can increased by 30 to 50 percent during both ebb and flood.
seyed Mahmood Kashefipour; Mehdi GHomeshi
Abstract
scouring and sedimentation is one of the most important topics in costal that always has been consider for river, coastal and marine structure engineers. Using RipRap is one of the simplest and economical methods for coastal protection that is very common because it is easily available, cheap and simple ...
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scouring and sedimentation is one of the most important topics in costal that always has been consider for river, coastal and marine structure engineers. Using RipRap is one of the simplest and economical methods for coastal protection that is very common because it is easily available, cheap and simple for construction and low costs. Rip Rap directly and indirectly used for protection of coastal against of erosion.one of the most important topics about is provide a criteria for its design and selection that has been less studied and available investigations are in straight route while due to flow pattern in the bends scouring is sever. The purpose of this study is provide a RipRap design criteria for protection of coastal against scouring. In order to achieve the research objectives, in the laboratory conditions evaluated one riprap size of inch diameter, lengths , distances and angels. The results showed equations for design of riprap and in another part of this study evaluate present equation of other researchers for using in the bends.