免费雷诺数计算器(进阶)
计算流体的雷诺数，判断层流或湍流状态。
Reynolds Number
100,000.00
Reynolds Number vs Fluid Density
公式
## 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.
计算示例
Water (rho = 1000, mu = 0.001) at 2 m/s through a 5 cm pipe.
- 01Re = rho v L / mu
- 02Re = 1000 * 2 * 0.05 / 0.001
- 03Re = 100 / 0.001 = 100 000
- 04This is well into the turbulent regime.
常见问题
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.
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