Dear,
After performing a hydraulic calculation
in WaterCAD when checking the results
I have some doubts, by subtracting the
elevation of the hydraulic gradient of
a node the value obtained differs in
decimals to the value of the pressure. Why does this happen?
I would also like to know what is the
difference between "pressure" and "pressure head"
Mathematically,
Pressure Head = P*ρg
where, ρ= mass density of water
g= acceleration due to gravity
P= Pressure.
ρg is almost equals 10. For eg. if the pressure at a junction is 1 Kg/cm2 then its pressure head turns out to be about 10 m H2O. Hope this helps. Happy modelling,
Tanay
I verify that the correct equation must be Pressure Head = P / ρ or Pressure Head = P / (ρ * g) when working for the pressure with Kg / m2 for the first case and with N / m2 for the second case. But when working empirically, the Pressure Head = 10 * Pressure is correct for pressure in Kg / cm2 and pressure head in meters