Calculateur de Nombre de Reynolds Avancé Gratuit

Calculez le nombre de Reynolds avec des options avancées. Déterminez le régime d'écoulement : laminaire, transitoire ou turbulent.

kg/m3
m/s
m
Pa s

Reynolds Number

100,000.00

Kinematic Viscosity0.00000100 m2/s

Reynolds Number vs Fluid Density

Formule

Reynolds Number

The Reynolds number predicts whether flow will be laminar (smooth) or turbulent (chaotic).

Formula

Re = rho v L / mu

  • *rho* = fluid density
  • *v* = flow velocity
  • *L* = characteristic length (pipe diameter, plate length)
  • *mu* = dynamic viscosity
  • For pipe flow: Re < 2300 is laminar, 2300-4000 is transitional, > 4000 is turbulent.

    Exemple Résolu

    Water (rho = 1000, mu = 0.001) at 2 m/s through a 5 cm pipe.

    1. 01Re = rho v L / mu
    2. 02Re = 1000 * 2 * 0.05 / 0.001
    3. 03Re = 100 / 0.001 = 100 000
    4. 04This is well into the turbulent regime.

    Questions Fréquentes

    What is the physical meaning of the Reynolds number?

    It represents the ratio of inertial forces to viscous forces. High Re means inertia dominates (turbulent); low Re means viscosity dominates (laminar).

    Why does the transition occur around Re = 2300?

    This is an empirical observation for smooth pipe flow. Small disturbances are damped by viscosity at low Re but amplified at high Re.

    Does the Reynolds number apply to gases?

    Yes. Gases have lower density but also lower viscosity, so Re can still be high for fast flows.

    Apprendre

    Understanding Newton's Laws of Motion

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