Computing nonhydrostatic shallow-water flow over steep terrain

Journal of Hydraulic Engineering
By:  and 



Flood and dambreak hazards are not limited to moderate terrain, yet most shallow-water models assume that flow occurs over gentle slopes. Shallow-water flow over rugged or steep terrain often generates significant nonhydrostatic pressures, violating the assumption of hydrostatic pressure made in most shallow-water codes. In this paper, we adapt a previously published nonhydrostatic granular flow model to simulate shallow-water flow, and we solve conservation equations using a finite volume approach and an Harten, Lax, Van Leer, and Einfeldt approximate Riemann solver that is modified for a sloping bed and transient wetting and drying conditions. To simulate bed friction, we use the law of the wall. We test the model by comparison with an analytical solution and with results of experiments in flumes that have steep (31°) or shallow (0.3°) slopes. The law of the wall provides an accurate prediction of the effect of bed roughness on mean flow velocity over two orders of magnitude of bed roughness. Our nonhydrostatic, law-of-the-wall flow simulation accurately reproduces flume measurements of front propagation speed, flow depth, and bed-shear stress for conditions of large bed roughness.

Publication type Article
Publication Subtype Journal Article
Title Computing nonhydrostatic shallow-water flow over steep terrain
Series title Journal of Hydraulic Engineering
DOI 10.1061/(ASCE)0733-9429(2008)134:11(1590)
Volume 134
Issue 11
Year Published 2008
Language English
Publisher ASCE
Description 13 p.
First page 1590
Last page 1602
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