Research progress on the application of dynamic grids in the numerical simulation of unsaturated-saturated interfaces

Abstract

In order to discuss the future development trend of structural and unstructured dynamic grid technology in the field of unsaturated-saturated groundwater numerical simulation, this paper summarizes the research status of unsaturated-saturated coupled numerical simulation, introduces the principle of dynamic grid technology and the deformation method of moving boundary structure and unstructured grid, summarizes the application status and shortcomings of dynamic grid technology in the unsaturated-saturated interface, and discusses the future development trend of related research. The review shows that both structural dynamic grids and unstructured dynamic grids have their inherent advantages and disadvantages, and the combination of structural/unstructured hybrid grids and multiple dynamic boundary treatment methods has important application value in the research of unsaturated-saturated coupling numerical simulation. When simulating the change of phreatic surface, a variety of mesh deformation methods can be combined. When the change of the position and shape of the phreatic surface is small, the spring method is used to update the mesh; When the position of the water table changes significantly but the shape changes little, the overlapping structure dynamic grid technology or the overlay method is used to update the grid; If the shape of the water table changes greatly, the grid reconstruction method is used to update the grid, so as to more accurately simulate the change and movement of the unsaturated-saturated interface. Relevant research provides scientific guidance for the coordinated prevention and control of unsaturated zone soil and saturated zone groundwater of the site.

Keywords

• dynamic grid
• unsaturated-saturated
• soil
• groundwater
• numerical simulation
• spring method
• overlapping structure dynamic grid technolog
• grid reconstruction method