Slope Limitation in Unsteady Models

[Anonymous]

The reference manual shows on page 2-17 that the slope in a steady flow model should be less than 1:10, due to the assumption on the hydrostatic pressure condition.

In the section regarding the unsteady models, there is no such assumption made. On pages 2-23 and following they show what the assumptions for the unsteady case are.

Does that mean that I could switch to an unsteady model if I have steeper slopes than 1:10?

(I have seen the conversion factors for the water depth, but that is a bit impractical in my case).

[Anonymous]

No.

The 1:10 slope limitation is a product of the cos(theta) in the solution for the solution for hydro static pressure…however the St Venant equations still base the solution on the same assumptions so the slope limitation ALWAYS applies. However when there are high slopes there are work arounds. One is to model the high slope as a straight drop through a virtual bridge.

[Anonymous]

Thank you for the clarification. Already figured that, even though it is only explicitly stated for the steady case I think.
As I need results also on the section with the large slope, I’ll have to look for some other model to get it done.

[Author]

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