In fluid dynamics, **turbulence** or **turbulent flow** is a flow regime characterized by chaotic and stochastic property changes. This includes low momentum diffusion, high momentum convection, and rapid variation of pressure and velocity in space and time. Nobel Laureate Richard Feynman described turbulence as "the most important unsolved problem of classical physics." Flow in which the kinetic energy dies out due to the action of fluid molecular viscosity is called laminar flow. While there is no theorem relating the non-dimensional Reynolds number (Re) to turbulence, flows at Reynolds numbers larger than 5000 are typically (but not necessarily) turbulent, while those at low Reynolds numbers usually remain laminar. In Poiseuille flow, for example, turbulence can first be sustained if the Reynolds number is larger than a critical value of about 2040; moreover, the turbulence is generally interspersed with laminar flow until a larger Reynolds number of about 3000. In turbulent flow, unsteady vortices appear on many scales and interact with each other. Drag due to boundary layer skin friction increases. The structure and location of boundary layer separation often changes, sometimes resulting in a reduction of overall drag. Although laminar-turbulent transition is not governed by Reynolds number, the same transition occurs if the size of the object is gradually increased, or the viscosity of the fluid is decreased, or if the density of the fluid is increased.

Read more about Turbulence: Features, Examples of Turbulence, Heat and Momentum Transfer, Kolmogorov's Theory of 1941

### Other articles related to "turbulence":

**Turbulence**Research

... The Center for Turbulence Research is a research consortium for studying turbulence ... It is jointly operated by Stanford University and NASA ...

**Turbulence**- Kolmogorov's Theory of 1941

... Richardson's notion of

**turbulence**was that a turbulent flow is composed by "eddies" of different sizes ... For homogeneous

**turbulence**(i.e ... This theory implicitly assumes that the

**turbulence**is statistically self-similar at different scales ...

... mixed layer is a layer in which active

**turbulence**has homogenized some range of depths ... The surface mixed layer is a layer where this

**turbulence**is generated by winds, cooling, or processes such as evaporation or sea ice formation which result in an increase in salinity ...

**Turbulence**typically plays a role in the formation of fluid mixed layers ...

... CHAOTICS' is a strategic business framework and platform for dealing with economic

**turbulence**defined and developed in 2008 by marketing guru Philip Kotler of Northwestern University ... companies to live with increased risk and uncertainty in an age of heightened

**turbulence**and its consequent chaos ... Business of Managing and Marketing in The Age of

**Turbulence**(AMACOM Publishing May 2009), globalization and technology are the two main forces have created a ...

...

**Turbulence**and radiative transfer are the most important physical processes that have to be parameterized in a prognostic mesoscale model ... For

**turbulence**parameterizations, K-theory is applied ... In case of MEMO

**turbulence**can be treated either with a zero-, one- or two-equation

**turbulence**model ...

### Famous quotes containing the word turbulence:

“their eyes still fixed, hoping to find once more,

Being by Calvary’s *turbulence* unsatisfied,

The uncontrollable mystery on the bestial floor.”

—William Butler Yeats (1865–1939)