滴灌入渗土壤水分分布的数值研究

The Water Content Distribution of Trickle Source Infiltration

采用 Brandt点源入渗柱状流物理模型和非迭代的交替向隐式差分法与牛顿迭代法相结合的数值方法对杨陵黏壤土滴灌水分入渗过程进行了模拟 ,并同室内实验结果进行了对比。结果表明在小滴头流量条件下 ,数值模型能够精确地用于对滴灌入渗湿润锋、湿润体内含水率分布的模拟。由于本模型在对入渗边界条件的处理上忽略了地表积水的体积 ,在大流量条件下 ,地表积水区域大且其形成主要发生在入渗的开始阶段 ,导致该阶段数值模拟的湿润体内水量较实际值偏低 2 5 %。

Brandt simulation model based on the metric flux potential concept was used to describe two-dimensional infiltration from a point source.The simulated wetting front indicated closer agreement with experiment data in case of small discharge rate,however,in case of big discharge rate,the simulated wetting front indicated disparity with experiment data,especially in initial infiltration time.The simulated soil water content distribution indicated closer agreement with experiment data.The applied water volume balance error analyses show that the error was 25% in initial time and the error decrease with time,after 200 min the applied water volume based soil water content simulated data is very close agreement with experiment.