EngiRef / Fluids Engineering Formula
Reynolds Number
Reynolds Number: Dimensionless number indicating laminar or turbulent flow. A Fluid Dynamics formula in fluids engineering. Variables Re, ρ, v, D and μ, each…
Fluid Dynamics
Specification
- Name
- Reynolds Number
- Discipline
- fluids
- Category
- Fluid Dynamics
- LaTeX
- Re = \frac{\rho vD}{\mu}
- Description
- Dimensionless number indicating laminar or turbulent flow
- Conditions
- Internal flow in circular pipes: laminar <~ 2300, turbulent >~ 4000
- Can solve for
- Re, ρ, v, D, μ
- Tags
- reynolds, laminar, turbulent, flow
Variables
| Symbol | Name | Unit | Si Unit | Imperial Unit |
|---|---|---|---|---|
| Re | Reynolds Number | - | - | - |
| ρ | Density | kg/m³ | kg/m³ | slug/ft³ |
| v | Velocity | m/s | m/s | ft/s |
| D | Characteristic Length | m | m | ft |
| μ | Dynamic Viscosity | Pa·s | Pa·s | - |
Common questions
- What is the Reynolds Number formula?
- Dimensionless number indicating laminar or turbulent flow. It sits under Fluid Dynamics, Fluids engineering in the EngiRef reference.
- What do the symbols in the Reynolds Number formula mean?
- In Reynolds Number, Re is reynolds number; ρ is density in kg/m³; v is velocity in m/s; D is characteristic length in m; μ is dynamic viscosity in Pa·s.
- When does the Reynolds Number formula apply?
- Reynolds Number holds under this condition: Internal flow in circular pipes: laminar <~ 2300, turbulent >~ 4000.