Science Fair Project Encyclopedia The Reynolds number is the
most important dimensionless number in fluid dynamics and
provides a criterion for determining dynamic similarity. Where
two similar objects in perhaps different fluids with possibly
different flowrates have similar fluid flow around them, they
are said to be dynamically similar. - vs - mean fluid velocity,
- L - characteristic length (equal to diameter 2r if a cross-
section is circular), - μ - (absolute) dynamic fluid viscosity,
- ν - kinematic fluid viscosity: ν = μ / ρ, - ρ - fluid density.
The Reynolds number is the ratio of inertial forces (vsρ) to
viscous forces (μ/L) and is used for determining whether a flow
will be laminar or turbulent. Laminar flow occurs at low
Reynolds numbers, where viscous forces are dominant, and is
characterized by smooth, constant fluid motion, while turbulent
flow, on the other hand, occurs at high Reynolds numbers and is
dominated by inertial forces, producing random eddies, vortices
and other flow fluctuations. T