Reynolds Number Calculator

Fluid Flow Analysis

Calculate the Reynolds number to determine flow regime (laminar, transitional, or turbulent) in pipes and channels.

Flow Parameters

Reynolds Number Formula

Re = (ρ × v × D) / μ

Where ρ is density, v is velocity, D is characteristic length (diameter), and μ is dynamic viscosity.

Flow Regimes

Laminar Flow
Smooth, orderly flow in parallel layers
Transitional Flow
Mixed flow characteristics, unstable
Turbulent Flow
Chaotic, irregular flow with eddies

Common Fluids

Water (20°C)
ρ = 1000 kg/m³, μ = 0.001 Pa·s
Air (15°C)
ρ = 1.225 kg/m³, μ = 0.0000181 Pa·s
Oil (SAE 30)
ρ = 920 kg/m³, μ = 0.29 Pa·s

Applications

  • Pipe flow design
  • Heat exchanger analysis
  • Aerodynamic studies
  • Chemical process engineering
  • HVAC system design