Figure:
Geometry of a discontinuous slope
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The discontinuous slope is the upstream element of a pair of boundary elements
simulating a change in slope. The corresponding downstream element is the
discontinuous opening.
Both are illustrated in Figure . The following constants have to be specified on the
line beneath the *FLUID SECTION,TYPE=CHANNEL DISCONTINUOUS SLOPE card:
- the width b
-
S_0 = \sin (\phi_1) (Figure ; if S_0<-1 the slope is calculated from the
coordinates of the end nodes belonging to the element)
- the length L_1 (Figure ; if L_1 \le 0 the length is calculated from the
coordinates of the end nodes belonging to the element)
- the trapezoid angle \theta
- the grain diameter k_s for the White-Colebrook law or the Manning
constant n for the Manning law (in the latter case the user has to specify
the parameter MANNING on the *FLUID SECTION card)
- the number of the upstream reference element
- not used
- the number of the downstream discontinuous opening element
- not used
The length L_1 is typically small compared to the length of the adjacent
channel branches.
Notice that a discontinuous slope element generally has upstream channel elements attached
to it. Therefore, it is always mandatory to specify an upstream reference element.
Example files: channel6.