Calculate and analyze Reynolds number instantly. Maximize accuracy and understand flow with confidence using this powerful and intuitive fluid dynamics tool.
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The Reynolds number (Re) is a key dimensionless quantity in fluid dynamics. It characterizes the flow of fluid by comparing inertial forces to viscous forces. This ratio helps engineers and scientists predict whether a flow will be smooth (laminar) or chaotic (turbulent).
The Reynolds number is defined by the formula:
Re = (ρ × U × L) / μUsing kinematic viscosity (ν = μ / ρ), the formula can also be expressed as:
Re = (U × L) / νResult:
Re = (1.2 × 5 × 0.3) / (1.8×10⁻⁵) = 100,000This high Re suggests turbulent flow, impacting noise and heat losses.
Result:
Re = (1060 × 0.4 × 0.004) / 0.0035 ≈ 484Indicates laminar flow, typical of healthy arteries.
Dh = 4 × A / P where A = area, P = wetted perimeter.Reynolds number plays a critical role in:
This calculator enables rapid analysis by accepting known flow properties and outputting the Reynolds number, enabling engineers and students to interpret fluid regimes efficiently.
Start calculating now and take the guesswork out of your fluid dynamics designs!
| Fluid | Pipe Diameter (mm) | Velocity (m/s) | Density (kg/m³) | Viscosity (Pa·s) | Reynolds Number |
|---|---|---|---|---|---|
| Water | 50 | 1.5 | 1000 | 0.001 | 75000 |
| Air | 100 | 2.0 | 1.2 | 1.8e-5 | 13333 |
| Oil | 25 | 0.2 | 900 | 0.1 | 45 |
| Microfluidic Channel | 0.5 | 0.01 | 1000 | 0.001 | 5 |
| Steam Pipe (Compressible) | 75 | 15 | 0.6 | 1.2e-5 | 562500 |
| Rectangular Duct (Hydraulic D) | 70* | 3.5 | 998 | 0.00089 | 274719 |
*Hydraulic diameter used in place of actual width/height