Question

What is the physical significance of the Reynolds number?. How is defined for external flow over a plate of length L.

Answer 1

`Re=(\rho\ v\ l)/(\mu )`

Step-by-step explanation:

Reynolds number:

Reynolds number describe the type of flow.If Reynolds number is too high then flow is called turbulent flow and Reynolds is low then flow is called laminar flow .

Reynolds number is a dimensionless number.Reynolds number given is the ratio of inertia force to the viscous force.

`Re=(F_i)/(F_v)`

For plate can be given as

`Re=(\rho\ v\ l)/(\mu )`

Where ρ is the density of fluid , v is the average velocity of fluid and μ is the dynamic viscosity of fluid.

Flow on plate is a external flow .The values of Reynolds number for different flow given as

`Reynolds\ number\is \ >\ 5 * 10 ^5\ then\ flow\ will\ be\ turbulent.`

`Reynolds\ number\is \ <\ 5 * 10 ^5\ then\ flow\ will\ be\ laminar.`