The present work adopts the COHERENS-SWAN model developed by the first author through coupling three-dimensional hydrodynamic model （COHERENS） and third-generation wave model （SWAN）. Inside the COHERENS-SWAN, the ...The present work adopts the COHERENS-SWAN model developed by the first author through coupling three-dimensional hydrodynamic model （COHERENS） and third-generation wave model （SWAN）. Inside the COHERENS-SWAN, the SWAN is regarded as a subroutine and the time- and space-varying current velocity and surface elevation are obtained from the COHERENS. Wave-enhanced bottom shear stress, wave induced surface mixing length and wave dependent surface drag coefficient have been introduced into the COHERENS. Secondly, as wave-enhanced bottom shear stress （＂bottom shear stress＂ described as BSS sometimes in this article） is concerned, a modified bottom shear stress Grant and Madsen model which introduces random wave field is given and introduced to COHERENS-SWAN. COHERENS-SWAN is also adopted to simulate three-dimensional flow in the Yellow River Delta with wave-current co-existing. Four numerical experiments were given to study the effects of wave-current interaction on enhancing bottom shear stress. The simulated current velocities, wave height and wave period match well with field measurement data. The simulated significant wave height and wave period for the case with considering the effects of current can give better agreement with measurement data than the case without involving the effects of current. The introduction of random wave generates lower the bottom shear stress than the case without introducing it. There are obvious differences between bottom shear stress of two way interaction and one way interaction. Velocity field obtained by the COHERENS-SWAN is reasonable according to previous studies and measurements.展开更多
The effects of waves on Surface Drag Coefficient （SDC） and surface mixing length were analyzed and discussed by carrying out three-dimensional current modeling for the Bohai Sea in the present work. A threedimension...The effects of waves on Surface Drag Coefficient （SDC） and surface mixing length were analyzed and discussed by carrying out three-dimensional current modeling for the Bohai Sea in the present work. A threedimensional coupled hydrodynamical-ecological model for regional and shelf seas （COHERENS） incorporating the influences of wave-current interactions was coupled with the third-generation wave model swan taking into account time-varying currents. The effects of waves on currents were included in the SDC, surface mixing length and bottom drag coefficient. Firstly, the formulations in Donelan were incorporated into the COHERENS to account for wave-dependent SDC. In order to compare simulation results for the wave-dependent SDC, the simulation for wind-dependent SDC was also carried out. Second, Wave-Induced Surface Mixing Length （described as WISML sometimes in this paper） was incorporated into the COHERENS. Four numerical experiments were conducted to discuss the effects of two kinds of wave processes. Generally, the values of time series of current velocity and water surface elevation given by the simulation with all of the three wave processes have a good agreement with observed data. The existence of WISML changes obviously current vertical profiles and the existence of the wave dependent SDC modifies the current field of both top and bottom layers with the wind-dependent SDC.展开更多
The coupled hydrodynamical-ecological model for Regional and Shelf Seas Coherens was modified through introducing sediment model in order to simulate suspended sediment transport and account for the interaction betwee...The coupled hydrodynamical-ecological model for Regional and Shelf Seas Coherens was modified through introducing sediment model in order to simulate suspended sediment transport and account for the interaction between turbulence and sediment. To discuss the effects of sediment on vertical eddy viscosity and diffusion coefficients, the damping function of sediment on turbulence was introduced into one equation k-ε turbulence closure model. Moreover, it is assumed that local equilibrium among turbulence production, dissipation and buoyancy destruction exist near the bottom. The local equilibrium assumption is introduced into the one equation k-ε model and the specific formulation of local equilihrium for one equation k-ε was derived. The tidal current was calculated for Youngkwang Bay near the west coast of Korea. Meanwhile, the suspended sediment was also simulated with the local equilibrium assumption and damping function of sediment on turbulence. It is found that the damping function of sediment reduces vertical eddy viscosity and diffusion coefficients. The local equilibrium assumption changes obviously bottom layer turhulence intensity and sediment concentration.展开更多
The hydrodynamic model COHERENS-SED, developed by the present authors through introducing wave-enhanced bottom stress, wave dependent surface drag coefficient, wave-induced surface mixing, SWAN to COHERENS, is modifie...The hydrodynamic model COHERENS-SED, developed by the present authors through introducing wave-enhanced bottom stress, wave dependent surface drag coefficient, wave-induced surface mixing, SWAN to COHERENS, is modified to account for wave-induced vertical mixing. The COHERENS-SED model can also be used for one-dimensional, two-dimensional, three-dimensional current and salinity calculations. One-dimensional model and three-dimensional model are used to study the effects of the wave-induced vertical mixing. The horizontal current velocity profiles obtained by the model are in good agreement with the analytical velocity profiles under the same input conditions. Numerical results show that higher wave height would generally generate larger vertical eddy viscosity and lower horizontal velocity. The results for fresh water in Yellow River Delta show that the wave-induced vertical mixing increases the momentum of fresh water transferring ability downwards to seabed and salt water＇s mixing with upper fresh water. Fresh water flume length is compressed considerably.展开更多
基金the National Basic Research Program of China (973 Program Grant No. 2002CB412408)the National Science Foundation of Shangdong Province (Grant No. Q2007E05).
文摘The present work adopts the COHERENS-SWAN model developed by the first author through coupling three-dimensional hydrodynamic model （COHERENS） and third-generation wave model （SWAN）. Inside the COHERENS-SWAN, the SWAN is regarded as a subroutine and the time- and space-varying current velocity and surface elevation are obtained from the COHERENS. Wave-enhanced bottom shear stress, wave induced surface mixing length and wave dependent surface drag coefficient have been introduced into the COHERENS. Secondly, as wave-enhanced bottom shear stress （＂bottom shear stress＂ described as BSS sometimes in this article） is concerned, a modified bottom shear stress Grant and Madsen model which introduces random wave field is given and introduced to COHERENS-SWAN. COHERENS-SWAN is also adopted to simulate three-dimensional flow in the Yellow River Delta with wave-current co-existing. Four numerical experiments were given to study the effects of wave-current interaction on enhancing bottom shear stress. The simulated current velocities, wave height and wave period match well with field measurement data. The simulated significant wave height and wave period for the case with considering the effects of current can give better agreement with measurement data than the case without involving the effects of current. The introduction of random wave generates lower the bottom shear stress than the case without introducing it. There are obvious differences between bottom shear stress of two way interaction and one way interaction. Velocity field obtained by the COHERENS-SWAN is reasonable according to previous studies and measurements.
基金Project supported by 973 Project (Grant No: 2002CB412408) and the Natural Science Foundation of Qingdao (Grant No: 03-jr-15).
文摘The effects of waves on Surface Drag Coefficient （SDC） and surface mixing length were analyzed and discussed by carrying out three-dimensional current modeling for the Bohai Sea in the present work. A threedimensional coupled hydrodynamical-ecological model for regional and shelf seas （COHERENS） incorporating the influences of wave-current interactions was coupled with the third-generation wave model swan taking into account time-varying currents. The effects of waves on currents were included in the SDC, surface mixing length and bottom drag coefficient. Firstly, the formulations in Donelan were incorporated into the COHERENS to account for wave-dependent SDC. In order to compare simulation results for the wave-dependent SDC, the simulation for wind-dependent SDC was also carried out. Second, Wave-Induced Surface Mixing Length （described as WISML sometimes in this paper） was incorporated into the COHERENS. Four numerical experiments were conducted to discuss the effects of two kinds of wave processes. Generally, the values of time series of current velocity and water surface elevation given by the simulation with all of the three wave processes have a good agreement with observed data. The existence of WISML changes obviously current vertical profiles and the existence of the wave dependent SDC modifies the current field of both top and bottom layers with the wind-dependent SDC.
文摘The coupled hydrodynamical-ecological model for Regional and Shelf Seas Coherens was modified through introducing sediment model in order to simulate suspended sediment transport and account for the interaction between turbulence and sediment. To discuss the effects of sediment on vertical eddy viscosity and diffusion coefficients, the damping function of sediment on turbulence was introduced into one equation k-ε turbulence closure model. Moreover, it is assumed that local equilibrium among turbulence production, dissipation and buoyancy destruction exist near the bottom. The local equilibrium assumption is introduced into the one equation k-ε model and the specific formulation of local equilihrium for one equation k-ε was derived. The tidal current was calculated for Youngkwang Bay near the west coast of Korea. Meanwhile, the suspended sediment was also simulated with the local equilibrium assumption and damping function of sediment on turbulence. It is found that the damping function of sediment reduces vertical eddy viscosity and diffusion coefficients. The local equilibrium assumption changes obviously bottom layer turhulence intensity and sediment concentration.
基金supported by the Natural National Science Foundation of China(Grant No.50809065)the National Science Foundation of Shangdong Province(Grant No. Q2007E05)supported by the Project from Korea Ocean Research and Development Institute "Study on wave-curre interaction and development of local wave and wave Setup prediction model"
文摘The hydrodynamic model COHERENS-SED, developed by the present authors through introducing wave-enhanced bottom stress, wave dependent surface drag coefficient, wave-induced surface mixing, SWAN to COHERENS, is modified to account for wave-induced vertical mixing. The COHERENS-SED model can also be used for one-dimensional, two-dimensional, three-dimensional current and salinity calculations. One-dimensional model and three-dimensional model are used to study the effects of the wave-induced vertical mixing. The horizontal current velocity profiles obtained by the model are in good agreement with the analytical velocity profiles under the same input conditions. Numerical results show that higher wave height would generally generate larger vertical eddy viscosity and lower horizontal velocity. The results for fresh water in Yellow River Delta show that the wave-induced vertical mixing increases the momentum of fresh water transferring ability downwards to seabed and salt water＇s mixing with upper fresh water. Fresh water flume length is compressed considerably.
