Accurate simulation of overland flow using the boundary fitted coordinate system method (BFCSM)
Overland flow generated on natural slopes is seldom characterized by surfaces with homogenous physical and hydraulic properties. Since the physical and hydraulic properties change from one point to another, a spatially distributed model is more desirable. Also since watersheds are not rectangular planar surfaces, as is most often treated in the current literature, some method of accurately representing the watershed boundary is essential. Accurate representation of watershed boundary is important under partial equilibrium conditions and to predict flow characteristics within a watershed. Currently available methods cannot reproduce the exact physical shape of the watershed, especially when the geometry is complex. Grid generation by means of Boundary Fitted Coordinate System method (BFCSM) is a powerful, efficient, and accurate method of representing any physical geometry accurately. This thesis discusses the application of this technique in overland flow modeling. The BFCSM involves fitting an irregular grid to the physical domain such that its boundaries are also grid lines, and then transforming this grid to an uniform orthogonal computational domain. This transformation is followed by the transformation of the hosted or governing equations of overland flow and its boundary conditions. The solution procedure is performed using conventional Finite-Difference techniques in the transformed domain. ^
Major Professor: Darrell I. Leap, Purdue University.