**Reynolds Number :**

It is the ratio between inertial forces and viscous forces.

It is shown by R_{N.}

**R**_{N}=F_{I}/F_{v}

Where F_{I} is the inertial forces between the layers of the fluid.

and F_{v} is the Viscous Forces.

**Units:**

As Reynolds number is the ratio, so it has no units.

There are two distinctly different types of fluid flow was demonstrated by Osborne Reynolds in 1883.

**Laminar Flow:**

The type of flow in which Fluid particles move in smooth layers or in lamination is called laminar flow.

If Reynolds number is is less than or equal to 2000 , the Flow will be laminar.

**Turbulent Flow:**

The type of flow in which fluid particles does not move in layers or lamination is called turbulent flow.

If Reynolds number is greater than 2000 then the flow will be turbulent.

**Significance of Reynolds number :**

The significance of Reynolds numberĀ is that we can estimate whether the flow is laminar or turbulent**.** Laminar flow occurs at low Reynolds number. By the definition **R _{N}=F_{I}/F_{v}** , We can see Reynolds number will be low if the viscous forces are dominant

**.**And Flow will be turbulent at high Reynolds number high Reynolds number will be when the internal forces will be high.

jack says

June 15, 2012 at 2:49 pmYou mean “inertial” forces, not “internal”.

admin says

June 27, 2012 at 9:10 pmThanks Jack. It is corrected now.