Dimensional Splitting Finite-Volume Method for Two-Dimensional Surface Water Flow Model in Basin Irrigation

The concept of major direction correction is proposed, which includes complete major direction correction, major direction correction without roughness, and no major direction correction, based on the dimensional splitting expression of a two-dimensional surface water flow model in surface irrigation. The dimensional splitting finite-volume methods for basin irrigation were developed based on the major direction correction and existing dimensional splitting numerical methods, in addition to the scalar dissipation finite-volume method. The simulation performance of two-dimensional surface water flow models of basin irrigation constructed by the dimensional splitting finite-volume methods were comparatively validated and analyzed based on basin irrigation experiments. The results show that the models based on the Strang dimensional splitting methods with complete major direction correction and major direction correction without roughness have similar simulation accuracy and convergence rates with the model based on the dimensional nonsplitting finite-volume method. By comparison, the models based on the Strang dimensional splitting methods with no major direction correction and major direction correction without roughness exhibit better water conservation ability and computational efficiency than the model based on the dimensional nonsplitting finite-volume method. Consequently, the Strang dimensional splitting method with major direction correction without roughness can be used as a numerical method in the development of two-dimensional surface water flow models for basin irrigation.