Fornula for no free flowing gate

[comaj]

Hello

In Reference manual are formulas (8-2) and (8-5) for no free flowing through the gate. When free flow is change to no free flow the computing formula is change from head "H" to "3H". Why the head is change from H to 3H? Is it OK? From which literature are take this formulas? (I am sorry for my bad english.)

[jarvus lunt]

I studied this before.

For 8-1

H = Zu - Zsp

For 8-2

H = Zu - Zd

For 8-1 the Head is the energy grade minus the SPILLWAY CREST.

For 8-2 the Head is the energy grade minus the DOWNSTREAM WATER SURFACE.

The program switches from 8-1 to 8-2 at 0.67 submergence. The 3 comes from 1 / (1-0.67) at the transition point.