Borda–Carnot equation (for open channel flows)


In fluid dynamics the Borda–Carnot equation is an empirical description of the mechanical energy losses of the fluid due to a (sudden) flow expansion. The Borda–Carnot loss equation is only valid for decreasing velocity, v1 > v2, otherwise the loss ΔE is zero – without mechanical work by additional external forces there cannot be a gain in mechanical energy of the fluid. For open channel flows the fluid’s mechanical energy loss is related to the total head loss. The pressure acts effectively as a form of potential energy.

Related formulas


ΔEThe fluid's mechanical energy loss per unit of fluid volume (J/m3)
ρDensity of the fluid (kg/m3)
gStandard gravity
ΔHThe total head loss (m)