The discontinuous opening is the downstream element of the boundary element pair defining
a change in channel slope. The following constants have to be specified on the
line beneath the *FLUID SECTION,TYPE=CHANNEL DISCONTINUOUS OPENING card:
- the width b
-
S_0 = \sin (\phi_2) (Figure ; if S_0<-1 the slope is calculated from the
coordinates of the end nodes belonging to the element)
- the length L_2 (Figure ; if L_2 \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 discontinuous slope element.
The length L_2 is typically small compared to the length of the adjacent
channel branches.
Example files: channel6.