Raid (hydraulic engineering)
In hydraulic engineering, an overflow is the discharge process over a weir , sometimes the weir itself is also referred to as an overflow. Similar to the measuring orifice , the overflow can be used to determine the flow rate. Essential in a raid is the transition from flowing to shooting (i.e. from slow to very fast flowing) drain; this transition occurs exactly at the overflow threshold .
The weir formula can be used to calculate overflows. The discharge coefficient takes into account the shape of the beam deflection.