Reynolds number is used to check whether the flow is laminar or turbulent. It is denoted by Re.
This number got by comparing inertial force with Viscous force.
Reynolds number formula is given by
$\rho$ is the density of the fluid,
V is the velocity of the fluid,
$\rho$ is the density of fluid,
$\mu$ is the viscosity of fluid,
L is the length or diameter of the fluid.
Reynolds number formula is used in the problems to find the Velocity (V), density ($\rho$), Viscosity ($\mu$) and diameter (L) of the fluid. It is dimensionless.The Kind of flow depends on value of Re
- If Re < 2000 the flow is Laminar
- If Re > 4000 the flow is turbulent
- If 2000 < Re < 4000 it is called transition flow.