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Sluice Gate

Figure 98: Sluice gate geometry
\begin{figure}\epsfig{file=Sluice.eps,width=10cm}\end{figure}

The sluice gate is the upstream element of a pair of boundary elements simulating a sluice. The downstream element is the sluice opening. Both are illustrated in Figure 98. The interesting point is that the gate height $ h_g$ may be part of the backwater curve, but it does not have to. If the lower point of the gate is higher than the fluid surface, it will not be part of the backwater curve.

If the gate door touches the water and the water curve is a frontwater curve (curve A in Figure 98) the volumetric flow $ Q$ is given by

$\displaystyle Q=b h_g \sqrt{2 g (h-h_g \sqrt{1 - S_0^2})},$ (38)

if the gate door does not touch the water and the water curve is a frontwater curve the volumetric flow $ Q$ is given by

$\displaystyle Q=b h_c \sqrt{2 g (h-h_c \sqrt{1 - S_0^2})},$ (39)

where $ h_c$ is the critical depth. If the gate door touches the water and the water curve is a backwater curve (governed by downstream boundary conditions, curve B in Figure 98)) the volumetric flow is given by

$\displaystyle Q=b h_g \sqrt{2 g (h-h_d \sqrt{1 - S_0^2})}.$ (40)

Finally, if the gate door does not touch the water and the water curve is a backwater curve the volumetric flow is given by

$\displaystyle Q=b h_d \sqrt{2 g (h-h_d \sqrt{1 - S_0^2})}.$ (41)

The following constants have to be specified on the line beneath the *FLUID SECTION,TYPE=CHANNEL SLUICE GATE card:

The slope $ S_0$ is used in case the gate door does not touch the water surface. The cross section of a sluice gate is supposed to be rectangular. Therefore, $ \theta$ is lacking in its definition. Notice that a sluice gate can have upstream channel elements attached to it. In that case it is mandatory to specify an upstream reference element.


Example files: channel1, chanson1.


next up previous contents
Next: Sluice Opening Up: Fluid Section Types: Open Previous: Straight Channel   Contents
guido dhondt 2012-10-06