In this work, a two-dimensional numerical model based on Delft3D modelling system was setup to study the tidal characteristics of the Red Sea. Besides that, analyses of available observed time series of surface elevat...In this work, a two-dimensional numerical model based on Delft3D modelling system was setup to study the tidal characteristics of the Red Sea. Besides that, analyses of available observed time series of surface elevations were carried out. Sensitivity analyses of the numerical model were carried out by testing different model parameters aiming at selecting optimal settings. The model performance was evaluated against available time series of surface elevation observations. RMS error was found to vary from 0.03 to 0.1 meter, while the ADM values range from 0.02 to 0.05 meter. On the whole, the model is able to reproduce the tidal wave in the Red Sea, reflecting a consistent level of agreement with the observations and previous works. The model results suggest that the semidiurnal tidal waves play a major role in the region except in the central part of the Red Sea where amphidromic system exists. Major semidiurnal and diurnal tidal constituents were computed to generate co-charts and form factor. The results have revealed that the distribution of the co-charts of the major semidiurnal constituents M2, N2, and S2 show the existence of anticlockwise amphidromic system in the central part of the Red Sea at about 19.5°N, north of the Strait of Bab el Mandeb at 13.5°N and in the Gulf of Suez. The chart of the diurnal tidal constituent K1 showed a single counterclockwise system in the southern part of the Red Sea centred around 15.5°N. The form factor chart shows the appearance of diurnal character in the central part of the basin and the northern end of the strait. The hydrodynamics patterns under spring and neap tidal conditions were also analysed (during flood and ebb conditions). Model results showed that currents generally are weak and strongest currents are present in the strait of Bab el Mandeb and Gulf of Suez.展开更多
The sea area east of Chenshan Cape has peak tidal current flows that exceed 2.3 m s^-1,which make it a promising site for the development of tidal current energy.Before these resources can be exploited,a comprehensive...The sea area east of Chenshan Cape has peak tidal current flows that exceed 2.3 m s^-1,which make it a promising site for the development of tidal current energy.Before these resources can be exploited,a comprehensive assessment is needed of the potential environmental impacts of the extraction of this energy.In this paper,we describe our construction of a three-dimensional hydrodynamic model of the waters near Chengshan Cape,and verify the performance of the model using continuous data measured in situ.We modeled the potential impacts of the exploitation of these resources on the flow field by adding a momentum loss term in the governing equation of the model.Simulation results show that an assumed tidal farm with an estimated power output of 20.34 MW would have a significant impact on the surrounding water level,especially next to the farm,where fluctuation could reach 6 cm.The maximum drop in the flow velocity in the wake of the farm was predicted to be more than 0.8 m s^-1,and this influence would extend 10 km downstream.展开更多
Al-Nakheel beach is located northwest of Alexandria city,Egypt,along the Mediterranean coast.During the period from 1998 to 2003,seven detached breakwaters were constructed along Al-Nakheel beach to create a sheltered...Al-Nakheel beach is located northwest of Alexandria city,Egypt,along the Mediterranean coast.During the period from 1998 to 2003,seven detached breakwaters were constructed along Al-Nakheel beach to create a sheltered area for swimming.Unfortunately,the structures amplify rip currents,shoreline accretions,and erosions.The aim of this research is to track the variations of the rip currents within the study area and show the effects of the breakwaters on the shoreline.The research is based on the hydrodynamic and morphological data of the study area and uses the Delft3D hydrodynamical model combined with other data analysis tools to serve the model input.The data include measured sea-level observations in 2013,the ERA-interim wave datasets from 2015 to 2018 and wind data in 2018,bed morphologies,and Google Earth satellite images from 2010 to 2020.The model is calibrated on the basis of the available current measurements within the nearshore zone.Results show that the shoreline eroded at an average rate of about 0.9 m/yr.Moreover,pairs of vortices are formed behind the breakwaters with an average current velocity of 0.6 m/s.The predominant northwest waves induce rip currents on the leeside of the structures with velocities reaching 1.2 m/s,associated with the rip pulsation that extends offshore.The problem solution decision recommends the removal of the sand deposition on the leeside of the breakwaters by an average amount of 100000 m3/yr and the fencing of the safe area for swimming by a floating fence of 1000 m length and 65 m average width.展开更多
文摘In this work, a two-dimensional numerical model based on Delft3D modelling system was setup to study the tidal characteristics of the Red Sea. Besides that, analyses of available observed time series of surface elevations were carried out. Sensitivity analyses of the numerical model were carried out by testing different model parameters aiming at selecting optimal settings. The model performance was evaluated against available time series of surface elevation observations. RMS error was found to vary from 0.03 to 0.1 meter, while the ADM values range from 0.02 to 0.05 meter. On the whole, the model is able to reproduce the tidal wave in the Red Sea, reflecting a consistent level of agreement with the observations and previous works. The model results suggest that the semidiurnal tidal waves play a major role in the region except in the central part of the Red Sea where amphidromic system exists. Major semidiurnal and diurnal tidal constituents were computed to generate co-charts and form factor. The results have revealed that the distribution of the co-charts of the major semidiurnal constituents M2, N2, and S2 show the existence of anticlockwise amphidromic system in the central part of the Red Sea at about 19.5°N, north of the Strait of Bab el Mandeb at 13.5°N and in the Gulf of Suez. The chart of the diurnal tidal constituent K1 showed a single counterclockwise system in the southern part of the Red Sea centred around 15.5°N. The form factor chart shows the appearance of diurnal character in the central part of the basin and the northern end of the strait. The hydrodynamics patterns under spring and neap tidal conditions were also analysed (during flood and ebb conditions). Model results showed that currents generally are weak and strongest currents are present in the strait of Bab el Mandeb and Gulf of Suez.
基金supported by the National Natural Science Foundation of China (No. 51479185)the Major Basic Research Project of Shandong Province (No. ZR 2017ZA0202)
文摘The sea area east of Chenshan Cape has peak tidal current flows that exceed 2.3 m s^-1,which make it a promising site for the development of tidal current energy.Before these resources can be exploited,a comprehensive assessment is needed of the potential environmental impacts of the extraction of this energy.In this paper,we describe our construction of a three-dimensional hydrodynamic model of the waters near Chengshan Cape,and verify the performance of the model using continuous data measured in situ.We modeled the potential impacts of the exploitation of these resources on the flow field by adding a momentum loss term in the governing equation of the model.Simulation results show that an assumed tidal farm with an estimated power output of 20.34 MW would have a significant impact on the surrounding water level,especially next to the farm,where fluctuation could reach 6 cm.The maximum drop in the flow velocity in the wake of the farm was predicted to be more than 0.8 m s^-1,and this influence would extend 10 km downstream.
文摘Al-Nakheel beach is located northwest of Alexandria city,Egypt,along the Mediterranean coast.During the period from 1998 to 2003,seven detached breakwaters were constructed along Al-Nakheel beach to create a sheltered area for swimming.Unfortunately,the structures amplify rip currents,shoreline accretions,and erosions.The aim of this research is to track the variations of the rip currents within the study area and show the effects of the breakwaters on the shoreline.The research is based on the hydrodynamic and morphological data of the study area and uses the Delft3D hydrodynamical model combined with other data analysis tools to serve the model input.The data include measured sea-level observations in 2013,the ERA-interim wave datasets from 2015 to 2018 and wind data in 2018,bed morphologies,and Google Earth satellite images from 2010 to 2020.The model is calibrated on the basis of the available current measurements within the nearshore zone.Results show that the shoreline eroded at an average rate of about 0.9 m/yr.Moreover,pairs of vortices are formed behind the breakwaters with an average current velocity of 0.6 m/s.The predominant northwest waves induce rip currents on the leeside of the structures with velocities reaching 1.2 m/s,associated with the rip pulsation that extends offshore.The problem solution decision recommends the removal of the sand deposition on the leeside of the breakwaters by an average amount of 100000 m3/yr and the fencing of the safe area for swimming by a floating fence of 1000 m length and 65 m average width.
