SWMM5 Normal Flow
Option " Define Supercritical Flow By " does inside the SWMM 5 engine. The options are called Slope , Froude and Both in the GUI and in the engine of SWMM 5. A few other variable definitions you need to know to understand this explanation are: (1) Y1 for the upstream link depth, (2) Y2 for the downstream link depth, (3) Q for the flow in the link, (4) Qfull for the full Manning's equation flow or normal flow for the link based on the bed slope, (5) Froude1 and Froude2 for the Froude Number respectively of the upstream and downstream ends of the link, (6) n for Manning's roughness, (7) Yfull for the maximum depth of the link and (8) Qnorma l for the Normal Flow equation flow based on the upstream area of the link ( A1 ) and the upstream hydraulic radius (R1 ). In the SWMM 5 engine these options are used after the dynamic wave equation flow is estimated using the St. Venant equation. The option that you choose is only active for those links that have a flow gr...