Calculate the Reynolds number to determine whether flow is laminar, transitional or turbulent.
The Reynolds number is the ratio of inertial to viscous forces, and it determines the flow regime: below about 2,300 flow is laminar, above 4,000 turbulent. Friction factor correlations differ entirely between the two regimes. Almost all industrial pipe flow is turbulent, which is why the laminar friction relationship is rarely the right one to use.
Reynolds Number
Re = ρ v L ÷ μ
Re = ρ v L ÷ μ The Reynolds number is the ratio of inertial to viscous forces, and it determines the flow regime: below about 2,300 flow is laminar, above 4,000 turbulent. Friction factor correlations differ entirely between the two regimes.
Almost all industrial pipe flow is turbulent, which is why the laminar friction relationship is rarely the right one to use.
This calculator takes 4 inputs: Fluid velocity, Pipe diameter or characteristic length, Fluid density, Dynamic viscosity. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.