A 2-D depth averaged RNG k- ε model is developed to simulate the flow in a typical reach of the Upper Yellow River with non-monotonic banks. In order to take account of the effect of the secondary flow in a bend, the...A 2-D depth averaged RNG k- ε model is developed to simulate the flow in a typical reach of the Upper Yellow River with non-monotonic banks. In order to take account of the effect of the secondary flow in a bend, the momentum equations are modified by adding an additional source term. A comparison between the numerical simulation and the field measurements indicates that the improved 2-D depth averaged RNG k- ε model can improve the accuracy of the numerical simulation. An arc spline interpolation method is developed to interpolate the non-monotonic river banks. The method can also be reasonably applied for the 2-D interpolation of the river bed level. Through a comparison of the water surface gradients simulated in the seven bends of the studied reach, some analytical formulae are improved to reasonably calculate the longitudinal and transverse gradients in meandering river reaches. Furthermore, the positions of the maximum water depth and the maximum velocity in a typical bend are discussed.展开更多
In order to study the flow characteristics in water bodies with rigid aquatic vegetation,series of laboratory experiments are carried out in an open channel,in which glass rods are used as plants with diameters of 6mm...In order to study the flow characteristics in water bodies with rigid aquatic vegetation,series of laboratory experiments are carried out in an open channel,in which glass rods are used as plants with diameters of 6mm,8mm and 10mm,respectively.For each diameter of glass rods,four typical cases are considered with various densities and arrangements of glass rods.The flow velocities in the four cases are measured by the 3-D laser Doppler velocimeter(LDV).The water surface slope,the flow velocity,the water head loss,the vegetation drag force and the hydraulic slope are calculated,analyzed and discussed.The horizontal,vertical and total vegetation densities in the vegetation area are defined and the relationship between these physical parameters and the water surface slope are studied.The head loss and the hydraulic slope in the vegetation area are also calculated,compared and analyzed.It is indicated that the water surface slope and velocity,the head loss and the hydraulic slope in the vegetation area have a close relationship with the arrangement,the density,and the plant diameter of the vegetation.展开更多
基金supported by the National Natural Science Foun-dation of China(Grant Nos.91230111,11361002)the Natural Science Foundation of Ningxia Hui Autonomous Region(Grant No.NZ13086)
文摘A 2-D depth averaged RNG k- ε model is developed to simulate the flow in a typical reach of the Upper Yellow River with non-monotonic banks. In order to take account of the effect of the secondary flow in a bend, the momentum equations are modified by adding an additional source term. A comparison between the numerical simulation and the field measurements indicates that the improved 2-D depth averaged RNG k- ε model can improve the accuracy of the numerical simulation. An arc spline interpolation method is developed to interpolate the non-monotonic river banks. The method can also be reasonably applied for the 2-D interpolation of the river bed level. Through a comparison of the water surface gradients simulated in the seven bends of the studied reach, some analytical formulae are improved to reasonably calculate the longitudinal and transverse gradients in meandering river reaches. Furthermore, the positions of the maximum water depth and the maximum velocity in a typical bend are discussed.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11861003,11761005).
文摘In order to study the flow characteristics in water bodies with rigid aquatic vegetation,series of laboratory experiments are carried out in an open channel,in which glass rods are used as plants with diameters of 6mm,8mm and 10mm,respectively.For each diameter of glass rods,four typical cases are considered with various densities and arrangements of glass rods.The flow velocities in the four cases are measured by the 3-D laser Doppler velocimeter(LDV).The water surface slope,the flow velocity,the water head loss,the vegetation drag force and the hydraulic slope are calculated,analyzed and discussed.The horizontal,vertical and total vegetation densities in the vegetation area are defined and the relationship between these physical parameters and the water surface slope are studied.The head loss and the hydraulic slope in the vegetation area are also calculated,compared and analyzed.It is indicated that the water surface slope and velocity,the head loss and the hydraulic slope in the vegetation area have a close relationship with the arrangement,the density,and the plant diameter of the vegetation.
