Engineering & mechanics
Pipe Reynolds number
Calculate Reynolds number with explicit density and dynamic viscosity.
A clear answer. Here’s how.
Uses Re=ρVD/μ, converting diameter to metres and dynamic viscosity to Pa·s. Classifies circular-pipe flow using conservative bounds below 2,000 and above 4,000, with a transitional interval between them. The physical transition depends on disturbances, geometry and conditions; these labels are not universal thresholds for all external or open-channel flows.
See a worked example
Worked example
A fixed demonstration, separate from the values you enter above.
- Fluid density (kg/m³)
- 1000
- Mean speed (m/s)
- 1
- Internal diameter (mm)
- 25
- Dynamic viscosity (mPa·s)
- 1
Example result
- Reynolds number
- 25,000
- Circular-pipe regime
- Turbulent
Uses 2,000 and 4,000 as conservative circular-pipe transition bounds; disturbances and geometry influence real transitions.