Selection of Δx and Δt Computational Steps for Four-Point Implicit Nonlinear Dynamic Routing Models

See related content

by D. L. Fread, Natl Weather Service, Silver Spring, United States,
J. M. Lewis, Natl Weather Service, Silver Spring, United States,

Document Type: Proceeding Paper

Part of: Hydraulic Engineering:

Abstract: A major step in a successful application of unsteady flow models based on the numerical (four-point implicit, nonlinear finite-difference) solution of the complete one -dimensional Saint-Venant equations, is the selection of the magnitudes of the computational distance step (δ x) and time step (δ t) used in the numerical solution technique. A theoretical explanation is presented for the basis of the empirical selection criteria used rather successfully for a number of years; also, an enhanced time step selection criterion is presented. The suitability of the selection criteria is demonstrated using a numerical convergence testing technique for a wide spectrum of unsteady flow applications ranging from rapidly to slowly rising hydrographs in very flat to very steep sloping channels.

Subject Headings: Numerical methods | Dynamic models | Hydraulic models | Numerical models | Approximation methods | Unsteady flow | Computer models | Computing in civil engineering |

Services: Buy this book/Buy this article


Return to search