A dimensionless quantity named after Osbourne Reynolds who first made know the difference between laminar and turbulent flow. The practical value of the Reynolds Number is that it indicated the degree of turbulence in a flowing liquid. It depends on the hydraulic radius of the conduit, the viscosity of the water and the velocity of flow. For a conduit of a given size, the velocity is generally the major variable and the Reynolds Number will increase as the velocity of flow increases.

Reynolds number ( Re) is a dimensionless quantity used in fluid mechanics, defined by Re = vl/ where is density, is velocity, is length, and is viscosity.

A dimensionless number that characterizes fluid flow through a system. At low Reynolds number, a fluid viscosity dominates the flow while at high Reynolds numbers, a fluid's inertia dominates.

an important dimensionless number associated with fluid flow and used in scaling fluid systems and in determining the transition point from laminar to turbulent flow. It represents the ratio of the momentum forces to the viscous forces in the fluid flow

A dimensionless number corresponding to the ratio of the fluid inertial force to the fluid viscous force in a flow system. It is used as an index for turbulence.

dimensionless ratio of dynamic and viscous forces used to determine the behaviour of fluids in any condition.

Non-dimensional ratio of viscous to inertial forces. Describes the flow pattern of a fluid

Flow similitude parameter, expressed as the ratio of the inertial force of the gas to the friction force of the gas moving over the surface of an object; flow Reynolds number the gas flow in a tube and parricle Reynolds number describes the gas flow around a particle. 1

A number that represents the relative importance of viscous forces and inertial forces in a fluid. As Re increases, inertial forces become more important. In sea water, Re increases with increasing water velocity and with the size of the object in the water

A non-dimensional number consisting of the product of velocity, density and length (duct diameter, blade length, etc.) divided by the dynamic viscosity of the air stream. The behaviour of air is varied by changes to these parameters and may be predicted by knowledge of the number.

A dimensionless parameter expressing the ratio between inertia and viscous forces at a specific cross section.

Any of several dimensionless quantities, of form LVp/N in theory of fluid motion.

the dimensionless ratio of inertial forces to viscous forces in flowing fluids. It may be viewed as a ratio of the shear stress due to turbulence to the shear stress due to viscosity. Flow with a Reynolds number less than 2000-4000 is laminar flow; that with a Reynolds number greater than 2000-4000 is turbulent flow.

Re) The ratio of inertial and viscous forces acting on an object. At Re 1 inertial forces are dominant; at Re 1, viscous drag, and not inertia, is most important. The latter scenario applies to a typical object in an optical trap, e.g. bacterium, latex bead. See Howard (2001) p. 38.

Dimensionless group used to indicate fluid flow regime with respect to viscosity. It is denoted by Re.

The ratio of inertial and viscous forces in a fluid defined by the formula Re = rVD/µ, where: r = Density of fluid, µ = Viscosity in centipoise (CP), V = Velocity, and D = Inside diameter of pipe.

The dimensionless ratio of the inertial force (âˆ¼) to the viscous force/ 2) in the Navierâ€“Stokes equations, where is a characteristic velocity, is a characteristic length, and Î½ is the kinematic viscosity of the fluid; thus, The Reynolds number is of great importance in the theory of hydrodynamic stability and the origin of turbulence. The inertia force generates vortex stretching and nonlinear interactions and hence creates randomness. Turbulence occurs when the inertia term dominates the viscous term, that is, when the Reynolds number is large. For many engineering flows, turbulence occurs when Re Rec, where the critical Reynolds number is roughly Rec = 2100. See large Reynolds number flow.

A mathematical factor used to express the relation between velocity, viscosity, density and dimensions in a system of flow. Used to define fan proportionality.

A nondimensional parameter representing the ratio of the momentum forces in fluid flow, named for English scientist Osborne Reynolds (1842-1912); among other applications, the ratio is vital to the use of wind tunnels for scale-model testing, as it provides a basis for extrapolating the test data to full-sized test vehicles

In fluid mechanics, the Reynolds number is the ratio of inertial forces (vsρ) to viscous forces (μ/L) and consequently it quantifies the relative importance of these two types of forces for given flow conditions. Thus, it is used to identify different flow regimes, such as laminar or turbulent flow. It is one of the most important dimensionless numbers in fluid dynamics and is used, usually along with other dimensionless numbers, to provide a criterion for determining dynamic similitude.