The Energy Equation

Integrate the momentum equation (1) along x to find the Energy Equation:

$$\Delta {\frac{u^2}{2g'}} \overline{(S_{P} - \frac{Cu^2}{g'h})} \Delta$$ (4)

The Froude number, F = u/(g'D)^1/2 = ((Q²b_T)/(g'A³))^1/2, determines the flow regime:

• if the Froude number is less than 1, flow is subcritical

• if the Froude number is greater than 1, flow is supercritical

• and if it is equal to 1, flow is critical