Prony equation
The
Prony equation is a historically important equation in
hydraulics, used to calculate the head loss due to
friction within a given run of pipe. It is an
empirical equation developed by
Frenchman Gaspard de Prony in the
19th century:
where
hf is the head loss due to friction, calculated from: the ratio of the length to
diameter of the pipe
L/D, the velocity of the flow
V, and two empirical factors
a and
b to account for friction.
This equation has been supplanted in modern hydraulics by the Darcy-Weisbach equation, which used it as a starting point.