涌泉根灌条件下土壤水分运动数值模拟研究

Numerical Simulation of Soil Water Movement under Bubbled Root Irrigation

依据非饱和土壤水动力学理论,采用计算机数值分析的方法,建立了涌泉根灌土壤水分三维入渗数值模拟模型,应用HYDRUS3D软件进行求解,得到了不同灌水流量下土壤水分运动规律。模拟所得土壤含水率与室内试验结果较接近,相对误差不超过12%。根据模拟结果分析涌泉根灌条件下土壤水分运动规律,分析了流量对湿润锋运移速率、最大水平扩散半径的影响。结果表明,土壤水分运动特征值随着流量的增大而变大,幅度随着时间的推移而减小,湿润体的最大水平扩散半径位置在孔洞底部以下5cm处;同一点处,随着灌水器流量的增大,湿润锋到达该点的时间越短,土壤含水率越大,增加的速率越快。

This paper built the numerical simulation model of soil water three-dimensional infiltration for Bubble Root Irrigation.Using HYDRUSE-3D software,the soil water movement under different flow conditions are analysised.The simulation results on soil moisture is very close to the laboratory tests.The maximum relative error between simulated and measured values is less than 12%.Based on the simulation results analysis the soil water movement under the condition of Bubble Root Irrigation,the effect of flux on wetting front migration rate and maximum horizontal diffusion radius were analysised.The results showed that the characteristics of soil water movement has grew larger as the flux was increased,the range was reduced over time,the position of the maximum horizontal diffusion radius of wetted body under the bottom of the hole 5 cm;At the same point,the wetting front reaches it would took shorter time as the flux was increased,the soil moisture content was greater,the rate of increasing was faster.