Enter the fluid velocity, pipe diameter, and kinematic viscosity into the calculator to determine the friction factor. A friction factor is a unitless measure of friction of a fluid moving through a pipe. It’s often used to help calculate energy loss as fluid moves through an opening.
Friction Factor Formula
The following formula is used to calculate the friction factor in laminar flow.
f = 64 / RE = 64 / (V*D/v)
- Where f is the friction factor
- V is the fluid velocity (m/s)
- D is the diameter of the pipe (m)
- v is the kinematic viscosity (m^2/s)
In the case of this formula, it can also be written as 64 / RE, where RE is the Reynold’s number = V*D/v
Friction Factor Definition
A friction factor is a measure of the friction force acting on a fluid moving through a pipe.
Friction Factor Example
The following is an example of calculating a friction factor.
- First, determine the velocity of the fluid. Measure the velocity of the fluid or calculate it. For this example we will assume a velocity of 25 m/s.
- Next, determine the diameter of the pipe. The pipe in this problem is said to be 25m in diameter.
- Next, determine the kinematic viscosity. Through empirical data or through published data on the fluid, we find the kinematic viscosity to be 10 m^2/s.
- Finally, calculate the friction factor using the formula. f = 64/(25*25/10) = 1.024.
A friction factor is a unitless measure of friction of a fluid moving through a pipe. It’s often used to help calculate energy loss as fluid moves through an opening.
The Reynolds number is a number , similar to a friction factor, that is a measure of the resistance to flow due to internal resistance as a fluid moves through a pipe.