Reynolds Number
Calculate Reynolds number from density, velocity, characteristic length, and dynamic viscosity.
How to use
- Enter density ρ, velocity v, and characteristic length L on compatible units.
- Enter dynamic viscosity μ and calculate.
Capabilities and scope
It evaluates the dimensionless inertia-to-viscosity ratio Re=ρvL/μ.
How it works
Re = density×velocity×length/dynamicViscosity.
Example
ρ=1000, v=1, L=0.01, μ=0.001 give Re=10000.
Useful for
- Compare inertial and viscous flow regimes
- Match Reynolds number between test conditions
Before you use it
- Laminar/turbulent transition thresholds depend on geometry, so Re alone does not universally classify flow.
Frequently asked questions
Can I enter kinematic viscosity ν?
This input form expects dynamic viscosity μ; using ν requires the alternative Re=vL/ν relation.