علوم غیرزیستی دریا
bagher behrooz; mohammadreza khalilabadi
Abstract
One of the main and effective components in the formation of hydrodynamic conditions and characteristics of coastal areas is tidal. In this research, the pattern of fluctuations in water level and tidal flow in Arvand River is studied. The results of these studies will be used for sedimentation, erosion ...
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One of the main and effective components in the formation of hydrodynamic conditions and characteristics of coastal areas is tidal. In this research, the pattern of fluctuations in water level and tidal flow in Arvand River is studied. The results of these studies will be used for sedimentation, erosion and coastal morphological changes. The purpose of this study was to evaluate and validate the Arvandrood plume numerical hydrodynamic model using field measurements at tidal stations and achieving a tidal plane pattern. This numerical model has been developed based on the Eulerian method and has been used to determine the pattern of flow of water flow from continuity and displacement equations. The hydrodynamic modulus is the basic modulus of the flow model, it is necessary to explain that this simulator module solves on a network with structure and governing equations using finite difference. In this research, a 70x70 depth-of-dimensional file system was networked, two open borders (the boundary of the sea and the upper boundary of the river) were considered for the model. The downstream boundary of the time series of water level changes was applied to the upstream boundary Water level changes have been applied to boundaries as a constant number. After calibration, the comparison of the model results with field measurements shows that the mean squared error for the water level level is 238 m and for the water velocity, it is 127.0 m / s.
علوم غیرزیستی دریا
mohamadreza mohamadifar; vahid chegini; MOHAMMAD ALI NAJARPOUR
Abstract
Wind waves are one of the most important environmental factors in marine engineering projects. due to the lack of measured wave data, predicted data are used to determine the climate of the waves. Today, numerical models have become the most practical tool for predicting wind waves. However, the results ...
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Wind waves are one of the most important environmental factors in marine engineering projects. due to the lack of measured wave data, predicted data are used to determine the climate of the waves. Today, numerical models have become the most practical tool for predicting wind waves. However, the results of these models are largely error-prone. Therefore, the outputs of numerical models have to be modified based on field data. A new approach used in the present study to modify the results of numerical model output variables in the computational domain is to create a local model and modify the results in boundary conditions which results in improved wave prediction in the computational domain. For this purpose, initial simulation of the waves (SWAN model) in Caspian Sea region was performed and the simulation results were compared with field data including Anzali, Noshahr and Offshore buoys. After initial simulation of the waves, the model parameter correction method is used to reduce error of the output results. By comparing the field data and the input data, we tried to approximate the results by applying the input parameter correction, which in turn improved the wave parameters and partly improved the simulation wave height. Then, a large-scale model of the entire Caspian Sea was implemented and then, a local model was defined, the boundary of which was slightly above the offshore deployment(located in the north of southern Caspian). The results show that using this method both the wave height and their periodicity are accurately predicted.
علوم غیرزیستی دریا
Somayeh Farhang Baftani; Mohammad Ali Najarpour; Masoud Sadrinasab
Abstract
Determination of causes affecting sedimentation is very important in oceanography. This study investigates mean annual sediment transport in Bolkheir port (and surrounding ports, Ameri and Rostami ports) after breakwater construction through modeling by Mike21 software. Results of this study show that ...
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Determination of causes affecting sedimentation is very important in oceanography. This study investigates mean annual sediment transport in Bolkheir port (and surrounding ports, Ameri and Rostami ports) after breakwater construction through modeling by Mike21 software. Results of this study show that construction of new breakwater and situation of Bolkheir port location (between two other ports) affect the sediment transport so that successive erosion and sedimentation frequentely occur in region between ports. Also two-dimensional sediment transport model shows gross cumulative rate of sediment transport. Rate of sediment transport in northern coast is about 5000 m3 /yr and in the southern coast is about 7000 m3 /yr . The annual rate of coastal sediment is 500 in backside of west arm of breakwater which is a meaningful amount of sediment.
علوم غیرزیستی دریا
Maryam Soyuf Jahromi; Zohreh Shahmansoori
Abstract
In this study, sea level anomaly of Persian Gulf (spatial resolution of 0.25 degrees of latitudes and longitudes) was investigated in the MATLAB software environment by using long-term AVISO data for 25 years (1 January 1993 to 31 December 2017). The 25-year average of the data shows that the sea level ...
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In this study, sea level anomaly of Persian Gulf (spatial resolution of 0.25 degrees of latitudes and longitudes) was investigated in the MATLAB software environment by using long-term AVISO data for 25 years (1 January 1993 to 31 December 2017). The 25-year average of the data shows that the sea level anomaly is positive and equals 3.06 ± 0.05 cm (mean± standard deviation), which is higher than the global average. Its range varies from a minimum of 2.46 cm to a maximum of 3.42 cm. The 25-year average of each season illustrates that sea level anomalies face a rise in autumn and a fall in spring. The two seasons of summer and winter are transition seasons from the maximum anomaly of autumn to the minimum anomaly of spring. The results also show that the spatial distribution of sea level anomaly in the basin is different. The mean sea level anomaly trend in the Persian Gulf is +2.9±0.1 mm/year, which practically divides Persian Gulf in the three parts of northwestern parts near the Arabian coast (anomalies less than 2.5 mm/year), the northern and central parts of the gulf (anomalies of 2.5-5.5 mm/year) and the southern part of the gulf and Strait of Hormuz (anomalies more than 3.5 mm/year). Therefore, although the head of Persian Gulf has positive trend changes, it is less than its southern part and near the Strait of Hormuz. If the Persian Gulf Sea level continues to rise, over the next 200 years, the Persian Gulf sea level will rise more than 0.5 m, with significant changes in the size and area of the basin.
علوم غیرزیستی دریا
Mohammad Taghi Zamanian; Masoud Sadrinasab; Mehri Fallahi
Abstract
The design of oceanic numerical model for Persian Gulf to predict oceanic phenomena and parameters is one of the most important ways of preventing or solving problems environment and designing of the oceanic model similar to it is an effective method that can explain physical response of environment ...
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The design of oceanic numerical model for Persian Gulf to predict oceanic phenomena and parameters is one of the most important ways of preventing or solving problems environment and designing of the oceanic model similar to it is an effective method that can explain physical response of environment to different situations. Purpose of this research is designing oceanic numerical model for environment similar to Persian Gulf, to predict its reaction in return effect of tide and wind. This three-dimensional model based on primitive equations in spherical coordinates system with sigma vertical coordinate. To solve equations of model is used finite difference method. Compared with similar models, model framework and calculate more logical tension between are the benefits of this model. An oceanic five-layer basin is considered with maximum and minimum depth 100m and 80.09m. The average daily wind in Persian Gulf, the average daily salinity and water temperature and the changes in the water level in Strait of Hormuz are used in this model. The two-year implementation of model showed that in this basin, the tidal force is a dominant force compared with windy force and density gradient, also the maximum current in strait is 1.98 m/s which can create anticlockwise circulation in basin. Maximum total change of water height is 2.98 m in relation to the static level. Implementation results of this model correspond to the oceanographic reality of Persian Gulf, while matches with purpose; it is the basis of suitable model for Persian Gulf.
علوم غیرزیستی دریا
Masoud Sadrinasab; Abbas Einali; Mohammad Akbarinasab; Mohammad Ali Najarpour
Abstract
Arvandrud River Plume which is the main source of fresh water in the Persian Gulf and in addition its catchment area is settlement for about 54 million people is one of the most important phenomena in costal zones. . The river is the boundary line between Iran and Iraq and its plume extended in Iran, ...
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Arvandrud River Plume which is the main source of fresh water in the Persian Gulf and in addition its catchment area is settlement for about 54 million people is one of the most important phenomena in costal zones. . The river is the boundary line between Iran and Iraq and its plume extended in Iran, Iraq and Kuwait territory in Persian Gulf. Oceanographic studies are infeasible in the river and in its mouth due to geographic, politics, and security problems in the region. Despite the lack of in-situ data, this study is a serious step to the investigation to river plume. In this study salinity, temperature and water circulation of Persian Gulf were simulated by using oceanographic hydrodynamic model, FVCOM. Then, effects of wind and river discharge on structure of Plumes were investigated. For this purpose, 14 wind and 8 river discharge conditions have been used. The results show the river has a surface-advected plume that is highly affected by wind. The river plume area decreased with increasing wind speed. Three types of plumes were formed by different wind conditions, at the mouth of the river. Plume type 1 diverted toward the northwest coast of Persian Gulf and plume type 3 diverted toward the Kuwait coast. Plume type 2 was almost straight and was not diverted to the sides. The T-S diagram of surface water mass was very similar to all three modes, as a result, the plume shape and displacement is affected by wind.
علوم غیرزیستی دریا
Atefe Pourkarimian; Maryam Soyuf Jahromi; Hossein Malakooti
Abstract
The new insights into ocean-atmosphere-land synoptic studies, have led scientists to trace attractive atmospheric and oceanic phenomena. In this study, by using synoptic maps and some precipitation indices for Iran, we estimated the type and intensity of the extreme precipitation event in Dayyer Port ...
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The new insights into ocean-atmosphere-land synoptic studies, have led scientists to trace attractive atmospheric and oceanic phenomena. In this study, by using synoptic maps and some precipitation indices for Iran, we estimated the type and intensity of the extreme precipitation event in Dayyer Port synoptical station (27˚51ʹ34ʺN-51˚57ʹ52ʺ, ID: 40872) for 19March 2017. In order to identify oceanic sources of the water content for this precipitation event, air parcels were traced as lagrangian single particle trajectory by a hybrid model of HYSPLIT which is run backward interactively on the web site, during 9-days by the start of maximum rainfall, locatacted at Dayyer port station. Accordingly, we plotted pattern of the average moisture transfer paths on 800-550 hPa atmospheric levels. The field climate data (including wind speed and direction, relative humidity and precipitation) with 6-hour time steps and spatial resolution of 2.5˚×2.5˚(longitude and latitude), entered into the model from the reanalysis global data archive of the National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR). Consequently, by assessment of the meteorological maps and data and by using a precipitation index of R10mm, we found that this precipitation event (19th March 2017) defined as a heavy precipitation day. Finally, the simulation outputs clearly showed that the water contents of this rainfall system (19th March 2017) originates from two source locations of the north area of Indian Ocean (Arabian Sea), and also the east part of Atlantic Ocean. In addition, the results illustrated that during the occurrence of this precipitation event, an extra-tropical cyclone was active on the studied area.
علوم غیرزیستی دریا
Ardeshir Farhadi; Mohammad Taghi Zamanian
Abstract
We have developed a basic three-dimensional finite difference hydrodynamic oceanic model using baroclinic primitive equations based on the earth's spherical coordinate modified by vertical sigma coordinate with eleven levels equivalent to five layers to study the thermodynamics of wind-driven currents. ...
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We have developed a basic three-dimensional finite difference hydrodynamic oceanic model using baroclinic primitive equations based on the earth's spherical coordinate modified by vertical sigma coordinate with eleven levels equivalent to five layers to study the thermodynamics of wind-driven currents. In this basic model, we consider an enclosed rectangle area, with constant depth of 120 m. We have simulated the horizontal velocity fields, salinity and temperature distributions by forcing the model with the steady bellowing wind over the area for four days with the speed of 10 m/s and direction . According to the Rossby number of the order of one tenth thousands, the large scale processes are dominated in the middle of such basins.The salinity and temperature of the layers are changed due to the diffusion and convection terms in the salinity and temperature equations, respectively.
علوم غیرزیستی دریا
Mahdieh Emami; Maryam Soyuf Jahromi; Alireza Behmanzadegan
Abstract
The coastline, as a border where the water flow is relatively impermeable, can change the flow pattern and therefore, the study of its hydrodynamic role is undeniable. in coastal engineering studies and even wet ecosystems even it is simple. In this study, using three-dimensional simulations in the numerical ...
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The coastline, as a border where the water flow is relatively impermeable, can change the flow pattern and therefore, the study of its hydrodynamic role is undeniable. in coastal engineering studies and even wet ecosystems even it is simple. In this study, using three-dimensional simulations in the numerical model environment of MIKE 3, the Danish Hydrodynamic Institute, two types of three dimensional simulations have been proposed using Navier Stokes equations to investigate the role of the coastline in rectangular and curved basins. In both simulations, it is assumed that the characteristics of Qeshm's tidal channel are scientifically established. This study clearly shows that the uniform velocity pattern in a rectangular basin changes with the curvature of coastline on the curved basin. The tightness in the curvature of the basin causes an increase in speed (about 0.05 m/s) in accordance with the principle of mass conservation. The opening after the turn of the basin causes a decrease of 0.1 m/s (0.4 m/s in the rectangular basin to 0.3 m/s in a curved basin, equivalent to 25% speed). Another point to consider is the role of water level changes. There is not much difference in the speed pattern between Higher High Water (HHW) and Lower Low Water (LLW) in Neap tide, but in the case of Spring tide where the water level is higher, the difference is 0.1 m/s in the rectangular basin and 0.2 m/s in the curved shape basin.
علوم غیرزیستی دریا
masoud sadrinasab; mohammad fayaz mohammadi; Vahid Chegini; amir ashtari larki
Abstract
Arvandrood is the most important shipping river at the border of Iran and Iraq at the north of the Persian Gulf. As the border is determined by the talweg of the river, the changes of the talweg, as a result of erosion and deposition, is always considering. As a reason of inertia, current of the river ...
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Arvandrood is the most important shipping river at the border of Iran and Iraq at the north of the Persian Gulf. As the border is determined by the talweg of the river, the changes of the talweg, as a result of erosion and deposition, is always considering. As a reason of inertia, current of the river tends to keep his direction forward. In meanders which the current has to change his direction, the sidewalls of the river experience severe shear stress that leads to sharp decrease of current energy and water level fluctuation, and increase of suspended sediment concentration. To simulate this in Arvandrood river, a 3D hydrodynamic model, DHI MIKE 21/3, has been employed. This model is based on a flexible mesh and the numerical solution of the two/three dimensional incompressible Reynolds averaged Navier-Stokes equations invoking the assumptions of Boussinesq and of hydrostatic pressure. In the first step, the model results were verified by the measured data in 4 stations. Comparing the water level in Faw position was shown that the Root Mean Square Error is 0.16 which is a good figure. Then, the model outputs were analyzed which show that in a straight direction of 18 kilometer from Abadan to Khosroabad, water level fluctuation and suspended sediment concentration have increased 18% and 3.8% respectively; while it is 22% and 15% in a way of 17 kilometer with two meander.
علوم غیرزیستی دریا
hakime moosazad; mohammad akbari nasab; Hossin Mashayekh Poul
Abstract
Three forcing processes can provide residual current: Tidal forces, wind forces, and density differences. Tidal residual current are created by tidal wave interaction with the structure of topography. In this study, two-dimensional model VOM-SW2d is applied In the barotropic and fully nonlinear to Pozm ...
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Three forcing processes can provide residual current: Tidal forces, wind forces, and density differences. Tidal residual current are created by tidal wave interaction with the structure of topography. In this study, two-dimensional model VOM-SW2d is applied In the barotropic and fully nonlinear to Pozm Bay in the northern coast of Oman to simulate the tidal residual currents. In this study aimed to investigate the effects of substrate unevenness, removed topography slope using high-pass filter. Regular computational grid has been used with a resolution of 150 m, in direction x and y. The results obtain the maximum current velocity of 0.05 m/s near the mouth of the Gulf of Pozm. Tidal residual current was observed of topographic features near the headland of Pozm Bay, headland at Pozm Bay and also in coastal areas due to the slope of the coast. Also the model results shows several eddies in different sizes and some Circulation in various scales. Tidal residual currents in the Pozm Bay, as depicted by Lagrangian trajectories reveal a stationary flow whit several eddies. Each eddy can be identified with a topographic obstacle. This confirms that the tidal residual flow field is strongly influenced by the nonlinear interaction of the tidal wave with the bottom relief which, in turn, is deformed by figure hills and valleys beneath the seabed
مهندسی دریا
M Kordnaeij; S.A Asghari Pari; S.M Sajjadi; M Shafai Bajestan
Abstract
In this study a porous obstacle was used to evaluate the performance of permeable obstacles for control of turbidity current. To build mathematical obstacle porous strata of 2.1 * 2.1 cm was used. 10 m long steep flume experiments are conducted. Tests were conducted in a double-dip 0 and 2.5 percent. ...
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In this study a porous obstacle was used to evaluate the performance of permeable obstacles for control of turbidity current. To build mathematical obstacle porous strata of 2.1 * 2.1 cm was used. 10 m long steep flume experiments are conducted. Tests were conducted in a double-dip 0 and 2.5 percent. Discharge constant in all tests was 0.7 liters per second. Feed concentration of 20 grams per liter of the concentrated flow and viscous flow in the upstream and downstream concentrations were measured porous barrier. Concentration was measured with use of a sampler flushing. The results showed that the porous barrier stepped porous barrier to the flow is better. Porous barrier stair staircase behind a thick flow of porous barrier and prevents over-stepped the stairs to the amount of sediment discharge reduced more.
علوم غیرزیستی دریا
Iman Khademi; Mohammad Akbarinasab; Abbas Ali Bidokhti; Mohammad reza Khalilabadi
Abstract
Turbulence is a form of movement characterized by an irregular or agitated motion. Turbulent motions are very common in nature. Most flows in the lower atmosphere and in the upper ocean are turbulent. The Turbulence has long had a special attraction for physicists and mathematicians; it has been called ...
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Turbulence is a form of movement characterized by an irregular or agitated motion. Turbulent motions are very common in nature. Most flows in the lower atmosphere and in the upper ocean are turbulent. The Turbulence has long had a special attraction for physicists and mathematicians; it has been called “the last great unsolved problem of classical physics”.In this study, hydrphysical measured data in the southern part of the Strait of Hormuz and with time step of half an hour during the period December 1996 to March 1998, by the University of Miami, and the meteorological station in island of Gheshm are used , then turbulence was simulated by General Ocean Turbulence Model (GOTM( . The results showed that, turbulent kinetic energy (TKE) in different seasons, with different penetration depths were appeared at during the year. In the cold season, the kinetic energy of the turbulent expands from surface to bottom and in the warm seasons because of existing the seasonal thermocline, depth penetration of TKE are limited, and only expands from surface to top of thermocline layer. In this study, investigation of the turbulent Prandtl number (Pr) shows that, effect turbulent viscosity Preference to the production buoyancy in the middle depth.
علوم غیرزیستی دریا
Parastoo Akbari; Masoud Sadrinasab; Vahid Chegini; Seyed Mostafa Siadat Mousavi
Abstract
Tide is one of the most regular changes of seas and ocean levels which are offering particular importance due to the influence on the flow pattern. According to engineering and environmental needs in industrial economic zone of Persian Gulf, Strait of Hormuz and Gulf of Oman, knowing the tidal characteristics ...
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Tide is one of the most regular changes of seas and ocean levels which are offering particular importance due to the influence on the flow pattern. According to engineering and environmental needs in industrial economic zone of Persian Gulf, Strait of Hormuz and Gulf of Oman, knowing the tidal characteristics of these areas is important. Therefore FVCOM (ocean model) was used to stimulate the tidal amplitude in an area comprising Persian Gulf, Strait of Hormuz, Gulf of Oman and Arabian Sea. Finite volume method is used in this model to discretize the hydrodynamic equations on triangular mesh. Uniform mesh is used with a resolution of 5 km in the model.The constant values of eight diurnal and semidiurnal tidal components are prescribed along the open boundary. In order to validate the model results, after applying harmonic analysis on the model outputs in desired stations, the achieved amplitude of this analysis compared with results which are obtained from the analysis on the available measurement data in these stations. According to the measurement and model results in these stations, meanwhile identifying the four main tidal components, the amplitude pattern of these components was determined in the whole domain. Also, by using amplitude of main components and estimating of F factor, the type of tide was predicted in the study area. Moreover, studying the maximum amounts of tidal velocity in the study area shows that the amount of this velocity in the Gulf of Oman and Arabian Sea is less than 0.1 m/s.
علوم غیرزیستی دریا
Abbas Einali; Vahid Chegini
Abstract
Pozm bay Located in southern coast of Iran near Oman Sea, due to its relative calmness, low depth and being affected by the land substances is interesting to some aquatics species for reproduction and spending part of their growth period. In this research the seasonal variations of physical parameters ...
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Pozm bay Located in southern coast of Iran near Oman Sea, due to its relative calmness, low depth and being affected by the land substances is interesting to some aquatics species for reproduction and spending part of their growth period. In this research the seasonal variations of physical parameters trend of the Pozm pay was investigated during 9 periods since Oct 2011 till Aug 2012. The physical parameters of the sea water were measured by the CTD device in 17 stations from surface to seabed. These parameters are as follows: Temperature, Salinity, Density, Electrical conductivity, Sound velocity, Turbidity, and the Dissolved oxygen. According to the results of this research, the variations of the water temperature are following the air temperature and increase as the air temperature arises in hot seasons. Although due to the low depth of Pozm bay the formation of thermocline layer and water stratification are so low, weak stratification is formed in water column during hot months of the year. The entering flow of Oman Sea water into the Persian gulf, which is less salty comparing to that of Persian gulf, is maximized during late spring and minimized in winter and affects the salinity of Pozm bay water such that its rate is more during mild months than hot months. The variation of the density is influenced by water temperature and the salinity has no effect on them. The summer monsoon has a significant effect on the physical parameters of Pozm bay's water.
مهندسی دریا
ahmad rezaie mazyak; mehdi sanayei
Abstract
The main goal of using floating breakwaters is to provide the sheltered area of calm water in the coastal zone. In present research, for analyzing hydrodynamic modeling of pontoon floating breakwaters the AQWA module of ANSYS software has been selected. The main parameters that have been considered in ...
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The main goal of using floating breakwaters is to provide the sheltered area of calm water in the coastal zone. In present research, for analyzing hydrodynamic modeling of pontoon floating breakwaters the AQWA module of ANSYS software has been selected. The main parameters that have been considered in this research are pattern of significant wave height, wave period, and draft and width of floating pontoon. Wave transmission coefficient can be obtained from water surface changes in any point of leeward. Results of numerical modeling demonstrate that a pontoon floating breakwater with relative width greater than 0.4 have appropriate performance. Also it has been found that the transmission coefficient of pontoon floating breakwaters will be in the range of 0.35 to 0.60 if the relative wave period changes in the range of 1.5 to 4.
مهندسی دریا
hossein bahrami; Mehdi ghomeshi; Seyed Mahmoud kashefi por; Seyed Ali Akbar Salehi Neyshabouri
Abstract
Density current is one of the relative motions that occur between two fluid layers, even in fluids with small difference in density. Differences in specific mass may cause of temperature, suspended material, solved material or a combination of them. These currents are so important specially in cases ...
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Density current is one of the relative motions that occur between two fluid layers, even in fluids with small difference in density. Differences in specific mass may cause of temperature, suspended material, solved material or a combination of them. These currents are so important specially in cases such as water containing sediment entering rivers into dam reservoir, seas or lakes and can also have destructive effects such as sedimentation in reservoir and estuaries to the sea and coastal areas as well as changing bedding sets Offshore areas (Kostic & Parker, 2005). The identification of type of move and change in current regime on the characteristics of the flow movement is very important. Investigation of flow movement, require to recognition of velocity profiles. A physical modeling used for this proposes and measurement and investigation of velocity on the body of current carried out. The results showed that the Coefficients of velocity profiles in wall and jet regions were respectively 2.83, 0.87 and 2.08 for sub critical flow and 1.174, 1.062 and 2.09 for super critical flow, also the maximum height of the supercritical flow was lower than sub critical flows. The other results showed that the velocity reduced 14 to 19 percent and the flow depth increased 21 to 32 percent affected by hydraulic jump respectively. Also, in some cases, large differences were observed between the results of the analytical jump relationship and measured data.
علوم غیرزیستی دریا
m s; a d; a a
Abstract
In the first step of developing of this software, we gathered some climate data which was collected during 20 years from the Persian Gulf. In the next step, climate data and boundary conditions were employed on a three dimensional hydrodynamic model (COHERENCE) to get physical properties of Persian Gulf. ...
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In the first step of developing of this software, we gathered some climate data which was collected during 20 years from the Persian Gulf. In the next step, climate data and boundary conditions were employed on a three dimensional hydrodynamic model (COHERENCE) to get physical properties of Persian Gulf. As a result we obtained a comprehensive density database from this model. Final produced software is able to calculate buoyancy force in specific time and location by its large database. The result of software show that the minimum seasonal average of draft occurs in the winter and the maximum one occurs in the summer. According to our expectancy, it has an inverse relation with density variation.According to our expectancy, it has an inverse relation with density variation
مهندسی دریا
khosro fazelpoor
Abstract
In order to provide SST images, the sensor MODIS installed on Aqua Satellite EOS-1 was used. Applying lighting assessment out of images from Modis 21-Level 1B Calibrated Radiances -1km in Persian Gulf and the Bushehr sea station (Bouyeh) from global algorithm specified for above sensor was used to estimate ...
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In order to provide SST images, the sensor MODIS installed on Aqua Satellite EOS-1 was used. Applying lighting assessment out of images from Modis 21-Level 1B Calibrated Radiances -1km in Persian Gulf and the Bushehr sea station (Bouyeh) from global algorithm specified for above sensor was used to estimate the sea surface temperature. With function of Matlab software to extract data of satellite images, and GIS software to convert the matris obtained, the maps of sea surface temperature were used. Forty eight images taken in 2008, 2009, 2012, and 2013 were selected. Their correlation coefficient eventually was 0.75, 0.86, and 0.75 respectively. Likewise the special coefficient obtained as 0.86, 0.90, 0.94 and 0.86 respectively. Finally, taking the 31 band temperature into consideration for the years 2008, 2009, 2012 and temperature differences of bands 31 and 32 and the sensor angle as independent factors were used at Bouyeh temperature as an affiliated factor calibrated by SPSS software for global algorithm of Persian Gulf. In order to check the correctness the algorithm suggested, the sea surface temperature was re-examined with satellite images of the year 2013; the correlation coefficient 0.96 and 0.94 were obtained. The searching has shown that the depth with current sea and latitude have effect on sea surface temperature, and temperature balance specially in north and central latitude have contrary relation with depth.
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.
علوم غیرزیستی دریا
Sahar j; Masoud t; a k
Abstract
Temperature is one of the fundamental parameters in physical oceanography and study of marine processes. The variation of Spatial and local of Sea Surface Temperature have an important role on climate change , life of fish, ocean currents, amount of salinity and the other carectistics of seas and lakes. ...
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Temperature is one of the fundamental parameters in physical oceanography and study of marine processes. The variation of Spatial and local of Sea Surface Temperature have an important role on climate change , life of fish, ocean currents, amount of salinity and the other carectistics of seas and lakes. The purpose of this research has predicted of sea surface temperature in the Caspian Sea. So the data on the Caspian Sea surface temperature (SST) that have been measured with Aqua satellite from MODIS sensor have been collected from 2003 to 2007 .This data analyzed by Fourier series method. Using Fourier analysis calculated Fourier coefficients and temperature predict for future year. Also average of sea surface temperature in three portion of Caspian Sea by 24 selected stations has been calculated. The pattern of sea surface temperature in different times of whole Caspian Sea during 2003-2007 was identified. The result of spectral time series is shown that temperature variation in different times have a same pattern. So in all stations spectral frequency have a 12 month periodic pattern.
علوم غیرزیستی دریا
Hosein Farjami; Mohammad Taghi Zamanian,; Akbar Rashidi Ebrahim Hesari,; Seiied Ali Azarmsa,
Volume 11, Issue 1 , November 2012, , Pages 41-48
Abstract
Wind is a major factor which induces oceanic currents and many theories including the Ekman theory have considered the wind induces currents. In this paper a numerical process has been used for forecasting of oceanic currents based on this theory. The survey has been done in an artificial five layer ...
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Wind is a major factor which induces oceanic currents and many theories including the Ekman theory have considered the wind induces currents. In this paper a numerical process has been used for forecasting of oceanic currents based on this theory. The survey has been done in an artificial five layer oceanic basin with smooth bottom of 120 meters, considering the geographic position of Persian Gulf. Primitive equations were solved on earth’s spherical coordinates system with sigma as vertical coordinate by finite element method. Vertical profile of predicted current vectors showed the complete formation of Ekman Spiral in the basin. This experimental simulation is a new approach for confirmation of Ekman Theory.