<Dl> <Dd> f D = 64 R e, (\ displaystyle f_ (\ mathrm (D)) = (\ frac (64) (\ mathrm (Re))),) </Dd> </Dl> <Dd> f D = 64 R e, (\ displaystyle f_ (\ mathrm (D)) = (\ frac (64) (\ mathrm (Re))),) </Dd> <P> where Re is the Reynolds number </P> <Dl> <Dd> R e = ρ μ ⟨ v ⟩ D = ⟨ v ⟩ D ν, (\ displaystyle \ mathrm (Re) = (\ frac (\ rho) (\ mu)) \ langle v \ rangle D = (\ frac (\ langle v \ rangle D) (\ nu)),) </Dd> </Dl>

Loss of head due to friction in pipes