Reynold’s Number | Definition, Formula – Hydrodynamics

Reynold’s Number Definition:
Reynold’s number is a pure number. It is equal to the ratio of the inertial force per unit area to the viscous force per unit area for a flowing fluid.

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Reynold’s Number | Definition, Formula – Hydrodynamics

Reynold’s Number Formula:
Reynold number,

K = \(\frac{\text { Inertial force }}{\text { Force of viscosity }}=\frac{v_{c} \rho r}{\eta}\)

where, vc = critical velocity.

For pure water flowing in a cylindrical pipe, K is about 1000.

  • When 0 < K < 2000, the flow of liquid is streamlined.
  • When 2000 < K < 3000, the flow of liquid is variable between streamlined and turbulent.
  • When K > 3000, the flow of liquid is turbulent.

It has no unit and dimension.

Hydrodynamics:
In physics, hydrodynamics of fluid dynamics explains the mechanism of fluid such as flow of liquids and gases. It has a wide range of applications such as evaluating forces and momentum on aircraft, prediction of weather, etc.

Flow of liquid Reynold’s Number
Equation of Continuity Energy of a Liquid
Bernoulli’s Principle Venturimeter
Torricelli’s Theorem Viscosity
Poiseuille’s Law Rate of Flow of Liquid
Stoke’s Law and Terminal Velocity Critical Velocity