摘要
基于二维畦灌全水动力学模型模拟的地表水深及畦面任意点垂向均布的流速场,通过把湍流垂向流速分布律由标量推广为矢量形式,并结合不可压缩流体力学连续性方程,构造了沿二维畦面及垂向非均布的三维流速场;利用能够描述二维畦面及垂向三个维度的溶质浓度场非均布变化特征的对流-扩散方程,描述传统撒施下的二维畦灌地表溶质运移过程,采用构造的三维流速场,基于湍流近壁模型构造了溶质扩散系数,从而构建了肥料撒施畦灌地表水流溶质运移控制方程;借助于畦灌地表水流模型中的薄水层假设,构建畦面溶质浓度初始条件,并采用一级动力学方程和任意点的固态溶质总量守恒特征,构建了撒施的肥料溶解与输运过程边界条件,从而构建起撒施肥料下的二维畦灌地表水流溶质运移模拟模型.
The surface water depth cross land was obtained numerically by simulating the 2D full hydrodynamics model in border irrigation firstly.Then the linear and logarithmic profile of turbulent velocity along the depth in scale form was extended to those in tensor one;subsequently,a non-uniform 3D flow velocity field across the land and along vertical direction was constructed by combining the continuous equation of incompressible hydrodynamics.Eventually,a convection-diffusion equation was adopted to describe the broadcasted fertilizer solute concentration across land and along depth of water in border irrigation.The diffusion coefficient was determined by using the nearby wall non-uniform flow velocity model.The initial condition was determined with the thin water layer hypothesis in surface water flow simulation of border irrigation.The overland boundary for solute dissolution and transpor-tation was imposed by using a first-order kinetics reaction model and mass conservation equation of solid fertilizer at a point.In this way,a fertilizer solute transport model is proposed in a 2D surface flow of border irrigation.
出处
《排灌机械工程学报》
EI
北大核心
2012年第1期112-116,124,共6页
Journal of Drainage and Irrigation Machinery Engineering
基金
国家863计划项目(2011AA100505)
国家科技支撑计划资助项目(2011BAD25B04)
关键词
肥料溶质
畦灌
撒施
非均布
流速场
溶质浓度场
fertilizer solute
border irrigation
conventional fertilization
non-uniform distribution
flow velocity field
solute concentration field
