Linking one- and two-dimensional models for free surface flows

This paper presents integration of a one-dimensional ( 1D) numerical model with a two-dimensional ( 2D) numerical model for simulating shallow water flows. The dynamic link library ( DLL) technique is used to link a 2D research code with a 1D commercial program. The 2D model has been refined to represent ground topography better and the flooding and drying process. Both mass and momentum transfers are allowed between the 1D and 2D solutions. Two test cases were used to verify the linked model. Smooth transitions between wet and dry areas were observed, with accurate mass conservation being achieved during wetting and drying. It has also been shown that the inclusion of momentum transfer between the two models leads to improved results by eliminating the unrealistic variations in the free surface, close to the common boundaries of the models. The combined 1D and 2D model has the capability to simulate hydraulic processes at different spatial scales simultaneously.