Ratio of inertial to viscous forces acting on a liquid
The plume from this candle flame transitions from laminar to turbulent.
The transition from laminar (left) to turbulent (right) flow of water from a tap occurs as the Reynolds number increases.
A vortex street around a cylinder. This can occur around cylinders and spheres, for any fluid, cylinder size, and fluid speed provided that it has a Reynolds number between roughly 40 and 1000.[1]George Stokes introduced Reynolds numbers.Osborne Reynolds popularised the concept.
In fluid dynamics, the Reynolds number (Re) is a dimensionless quantity that helps predict fluid flow patterns in different situations by measuring the ratio between inertial and viscous forces.[2] [fluid dynamics citation needed] At low Reynolds numbers, flows tend to be dominated by laminar (sheet-like) flow, while at high Reynolds numbers, flows tend to be turbulent. The turbulence results from differences in the fluid's speed and direction, which may sometimes intersect or even move counter to the overall direction of the flow (eddy currents). These eddy currents begin to churn the flow, using up energy in the process, which for liquids increases the chances of cavitation.
The Reynolds number has wide applications, ranging from liquid flow in a pipe to the passage of air over an aircraft wing. It is used to predict the transition from laminar to turbulent flow and is used in the scaling of similar but different-sized flow situations, such as between an aircraft model in a wind tunnel and the full-size version. The predictions of the onset of turbulence and the ability to calculate scaling effects can be used to help predict fluid behavior on a larger scale, such as in local or global air or water movement, and thereby the associated meteorological and climatological effects.
The concept was introduced by George Stokes in 1851,[3] but the Reynolds number was named by Arnold Sommerfeld in 1908[4] after Osborne Reynolds (1842–1912), who popularized its use in 1883.[5][6]
In fluid dynamics, the Reynoldsnumber (Re) is a dimensionless quantity that helps predict fluid flow patterns in different situations by measuring the...
In magnetohydrodynamics, the magnetic Reynoldsnumber (Rm) is a dimensionless quantity that estimates the relative effects of advection or induction of...
determined by a dimensionless parameter characterizing the flow called the Reynoldsnumber, which also depends on the viscosity and density of the fluid and dimensions...
spheres in uniform flow in the Reynoldsnumber range of 8×102 < Re < 2×105 there co-exist two values of the Strouhal number. The lower frequency is attributed...
kg/m3). Note that whereas the Reynoldsnumber and Grashof number are subscripted with a scale variable, the Prandtl number contains no such length scale...
Reynoldsnumber R e {\displaystyle \mathrm {Re} } , Mach number M a {\displaystyle \mathrm {Ma} } and the direction of the flow. For low Mach number M...
flow of an inviscid fluid which is a fluid with zero viscosity. The Reynoldsnumber of inviscid flow approaches infinity as the viscosity approaches zero...
situations where the Reynoldsnumber and Schmidt number are readily available. Since Re and Sc are both dimensionless numbers, the Sherwood number is also dimensionless...
non-dimensional form that relates the Darcy–Weisbach friction factor fD, Reynoldsnumber Re, and surface roughness for fully developed flow in a circular pipe...
pipe. The onset of turbulence can be predicted by the dimensionless Reynoldsnumber, the ratio of kinetic energy to viscous damping in a fluid flow. However...
transformations. Physics relies on dimensionless numbers like the Reynoldsnumber in fluid dynamics, the fine-structure constant in quantum mechanics...
breakthrough role was as Lewis Medlock in Deliverance (1972). Reynolds played leading roles in a number of subsequent box-office hits such as White Lightning...
Coulter Reynolds (born July 14, 1987) is an American singer and songwriter. He is the lead vocalist of the pop rock band Imagine Dragons. Reynolds also released...
of situations involving natural convection and is analogous to the Reynoldsnumber (Re). Free convection is caused by a change in density of a fluid due...
varies over a range of very cold temperatures. In fluid mechanics, the Reynoldsnumber is the ratio of inertial forces (vsρ) to viscous forces (μ/L). It is...
Ryan Rodney Reynolds OBC (born October 23, 1976) is a Canadian and American actor, producer, and businessman. He began his career starring in the Canadian...
very large experimental time, for example. In fluid mechanics, the Reynoldsnumber is a measure of the ratio of inertial forces ( v s ρ {\displaystyle...
Mary Frances "Debbie" Reynolds (April 1, 1932 – December 28, 2016) was an American actress, singer, and businesswoman. Her career spanned almost 70 years...
depends on the Reynoldsnumber; if the fluid is a gas, c d {\displaystyle c_{\rm {d}}} depends on both the Reynoldsnumber and the Mach number. The equation...
\lambda } ≈ 8×10−8 m (80 nm). The Knudsen number can be related to the Mach number and the Reynoldsnumber. Using the dynamic viscosity μ = 1 2 ρ c ¯...
The Reynolds and Reynolds Company is a private corporation based in Dayton, Ohio. Its primary business is providing business forms, management software...
{\text{Fr}}} is the Froude number, Re {\displaystyle {\text{Re}}} is the Reynoldsnumber, and We {\displaystyle {\text{We}}} is the Weber number. The influence of...
performs a reciprocal motion cannot achieve net displacement in a low-Reynoldsnumber Newtonian fluid environment, i.e. a fluid that is highly viscous. Such...
are three main ways to simulate high Reynoldsnumber, since it is not practical to obtain full scale Reynoldsnumber by use of a full scale vehicle.[citation...
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