沟灌土壤水分运动数值模拟与入渗模型
Infiltration model and numerical simulation of the soil water movement in furrow irrigation
-
摘要: 为进一步探明沟灌二维土壤水分运动规律,以非饱和土壤水分运动理论为基础,建立了沟灌土壤水分运动数学模型,用多组试验资料对模型模拟结果进行验证,两者基本吻合,表明模型可用于模拟沟灌二维土壤水分入渗过程.用所建模型对不同因素组合下沟灌土壤湿润体特性进行模拟分析,结果表明:土壤初始含水率、沟间距对沟灌累积入渗量影响较小,土壤质地、容重、沟底宽和沟中水深对其影响较为显著;沟底宽、土壤初始含水率对土壤湿润体水分分布影响较小,土壤质地、容重对其影响较大,沟间距、沟中水深对其影响主要在零通量面附近,当入渗发生交汇后,零通量面处垂向湿润锋运移加快.以此为基础,建立了包含湿周在内的沟灌累积入渗量计算模型.Abstract: Based on unsaturated soil water movement theory,the mathematical model of furrow irrigation is developed to un-derstand the characteristic of Two-dimensional soil water movement in furrow irrigation.The simulation results are verified by the laboratory experiments and agreed well with the experiments measurement values,which shown that the mathematical model can be used to study the two-dimensional soil water infiltration in furrow irrigation.The soil wetted volume characteristic of furrow irrigation are simulated and analyzed under different factor combination by this model,the results indicate that soil initial water content and furrow spacing have slight effect on the accumulation infiltration quantity of furrow irrigation,meanwhile the soil character,bulk density,water depth and bottom width have obvious effect on the accumulation infiltration quantity.The bottom width and soil initial water content have a littler influence on the wetting pattern and the wetting soil movement migration,but the soil character and bulk density have a great influence on it.The water depth and furrow spacing have an effect on the water contribution near the zero flux plane,the vertical moist front migration has accelerated after interference infiltration near the zero flux plane.Taking these results as the foundation,the two-dimensional infiltration model for furrow irrigation was established which contained the wetted perimeter.