Orifice property sheet

Like the weir tool, this special orifice tool can be used with the Full Unsteady hydraulic model to provide multiple outlets from detention basins, which can be subject to tailwater influence.

The inputs to the property sheet for the orifice consist of the name (of up to 10 characters) and various characteristics of the orifice. It can be a circular orifice with the diameter specified, or a rectangular orifice with the width and height specified. An orifice coefficient is also required. The 'No flow elev' (m)' refers to the bottom or invert of the circular orifice.

A wizard is now available to define circular orifice diameters needed to meet specific discharge and head requirements. A similar wizard is available for conventional basins with a single orifice.

The orifice object can be bent in the middle, by dragging and dropping the 'O' at the centre. This facilitates the specification of several orifices or weirs located with the same end points, as shown below.