This calculator determines Reynolds number, which is the ratio of the inertia forces to the friction forces in flow. Reynolds number is used to determine the transition from laminar flow to turbulent flow in pipes.
To help solve Reynold's Number, two extra calculators are provided for conversion purposes.
Calculation
Reynolds Number Calculator
Inputs
ρ
:1,000kg/m3
u
:1.00m/s
L
:1.00m
μ
:1.00Pa s
Output
Re
:1000
Laminar:
Re<2300
Transitional:
2300<Re<4000
Turbulent:
Re>4000
The equation for Reynolds number is given by:
Re=μρ×u×L
Where:
ρ
is the density of the fluid
(kg/m3)
u
is the mean velocity of flow
(m/s)
l
is the characteristic linear length, such as the diameter of a pipe or the chord length of an airfoil
(m)
μ
is the dynamic viscosity, which is a fluid property that describes the fluid's resistance to flow
(m⋅skg,Pa⋅s)
. A higher
μ
means the fluid will flow more slowly for a given applied force.
Re
is Reynolds number (dimensionless)
Characteristic Length of a Non-circular Tube
Kinematic Velocity to Dynamic Viscosity Convertor
Explanation
What is Reynolds Number?
Reynold's number, denoted by
Re
, is a dimensionless number that describes the flow of a fluid. In aerospace engineering, aircraft design can be based on Reynolds number.
💡Who was Osborne Reynolds?
Laminar vs Turbulent Flow
Reynold's number can be defined as the ratio of internal forces to the viscous forces within a fluid experiencing relative internal movement due to different fluid velocities.