Robustness of de Saint Venant equations for simulating unsteady flows

Robert A. Baltzer; Raymond W. Schaffranek; Chintu Lai

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Robustness of de Saint Venant equations for simulating unsteady flows

Robert A. Baltzer·Raymond W. Schaffranek·Chintu Lai

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Abstract

Long-wave motion in open channels can be expressed mathematically by the one-dimensional de Saint Venant equations describing conservation of fluid mass and momentum. Numerical simulation models, based on either depth/velocity or water-level/discharge dependent-variable formulations of these equations, are typically used to simulate unsteady open-channel flow. However, the implications and significance of selecting either dependent-variable form - on model development, discretization and numerical solution processes, and ultimately on the range-of-application and simulation utility of resulting models - are not well known. Results obtained from a set of numerical experiments employing two models - one based on depth/velocity and the other on water-level/discharge equation formulations - reveal the sensitivity of the two equation sets to various channel properties and dynamic flow conditions. In particular, the effects of channel gradient, channel width-to-depth ratio, flow-resistance coefficient, and flow unsteadiness are analyzed and discussed.

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Robert A. Baltzer, Raymond W. Schaffranek, Chintu Lai. 1995. Robustness of de Saint Venant equations for simulating unsteady flows. https://pubs.usgs.gov/publication/70018801

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