Orifice Critical Depth for Separating Weir Flow from Orifice Flow for Bottom Outlet Orifices in SWMM 5
Note: Orifice Critical Depth for Separating Weir Flow from Orifice Flow for Bottom Outlet Orifices The Critical height is the opening where weir flow turns into orifice flow . It equals (Co/Cw)*(Area/Length) where Co is the orifice coeff., Cw is the weir coeff/sqrt(2g), Area is the area of the opening, and Length = circumference of the opening. For a basic sharp crested weir , Cw = 0.414. All of the units are based on the internal SWMM 5 units of American Standard. For a circular orifice the Critical Height is: Critical Height = Orifice Discharge Coefficient / 0.414 * Orifice Opening / 4 For a rectangular orifice the Critical Height is: Critical Height = Orifice Discharge Coefficient / 0.414 * ( Orifice ...