### Sluice Opening

The sluice opening element is always adjacent to a sluice gate element on its downstream side. Both are illustrated in Figure 120. The sluice opening element has the gate door located at its upstream end node. Since the water depth in the downstream end node of this element should represent the depth just downstream of the gate door, the length of this element should be chosen to be particularly small. The following constants have to be specified on the line beneath the *FLUID SECTION,TYPE=CHANNEL SLUICE OPENING card:

• the width
• the slope (if the slope is calculated from the coordinates of the end nodes belonging to the element)
• the length (if the length is calculated from the coordinates of the end nodes belonging to the element)
• the trapezoid angle
• the grain diameter for the White-Colebrook law or the Manning constant 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 sluice gate element

The meaning of , , and can be derived from Figure 119.

Example files: channel1, chanson1.