Laminar flow (bottom) and turbulent flow (top) over a submarine hull.

Laminar flow, sometimes known as streamline flow, occurs when a fluid flows in parallel layers, with no disruption between the layers. In fluid dynamics, laminar flow is a flow regime characterized by high momentum diffusion, low momentum convection, and pressure and velocity independence from time. It is the opposite of turbulent flow. In nonscientific terms laminar flow is "smooth," while turbulent flow is "rough." The USS Los Angeles (SNN 688) Source: http://www. ... The USS Los Angeles (SNN 688) Source: http://www. ... Solid blue lines and broken grey lines represent the streamlines. ... Fluid dynamics is the sub-discipline of fluid mechanics dealing with fluids (liquids and gases) in motion. ... In classical mechanics, momentum (pl. ... This article or section does not cite any references or sources. ... Convection in the most general terms refers to the internal movement of currents within fluids (i. ... The use of water pressure - the Captain Cook Memorial Jet in Lake Burley Griffin in Canberra, Australia. ... This article or section does not cite its references or sources. ... A pocket watch, a device used to tell time Look up time in Wiktionary, the free dictionary. ... Turbulent flow around an obstacle; the flow further away is laminar Laminar and turbulent water flow over the hull of a submarine Turbulence creating a vortex on an airplane wing In fluid dynamics, turbulence or turbulent flow is a flow regime characterized by low-momentum diffusion, high momentum convection, and...

The (dimensionless) Reynolds number is an important parameter in the equations that describe whether flow conditions lead to laminar or turbulent flow. In laminar flow, the Reynolds number is less than 2100. Creeping motion or Stokes flow, an extreme case of laminar flow where viscous (friction) effects are much greater than inertial forces, occurs when the Reynolds number is much less than 1. In dimensional analysis, a dimensionless number (or more precisely, a number with the dimensions of 1) is a pure number without any physical units. ... 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. ... Stokes flow (named for George Stokes) is a type of flow where inertial forces are small as compared to viscous forces. ... Stokes flow is a type of flow where inertial forces are small as compared to viscous forces. ...

For example, consider the flow of air over an airplane wing. The boundary layer is a very thin sheet of air lying over the surface of the wing (and all other surfaces of the airplane). Because air has viscosity, this layer of air tends to adhere to the wing. As the wing moves forward through the air, the boundary layer at first flows smoothly over the streamlined shape of the airfoil. Here the flow is called laminar and the boundary layer is a laminar layer. A Laughing Gull with its wings extended in a gull wing profile Aircraft wing planform shapes: a swept wing KC-10 Extender (top) refuels a trapezoid-wing F/A-22 Raptor A wing is a surface used to produce lift and therefore flight, for travel in the air or another... In physics and fluid mechanics, the boundary layer is that layer of fluid in the immediate vicinity of a bounding surface. ... Viscosity is a measure of the resistance of a fluid to deform under shear stress. ... This article does not cite its references or sources. ...

As the boundary layer approaches the centre of the wing, it begins to lose speed due to skin friction and becomes thicker and turbulent. Here it is a turbulent layer. The process of a laminar boundary layer becoming turbulent is known as boundary layer transition. The point at which the boundary layer changes from laminar to turbulent is called the transition point. Where the boundary layer becomes turbulent, drag, due to skin friction, is relatively high. As speed increases, the transition point tends to move forward. As the angle of attack increases the transition point also tends to move forward. One way to limit the size and effect of the turbulent region is to use swept-back delta wings. This is particularly important in supersonic aircraft. In Aerodynamics, skin friction is the component of parasitic drag arising from the friction of the fluid against the skin of the object that is moving through it. ... The process of a laminar boundary layer becoming turbulent is known as boundary layer transition. ... In the field of fluid dynamics the point at which the boundary layer changes from laminar to turbulent is called the transition point. ... In this diagram, the black arrow represents the direction of the wind. ... The delta-wing is a wing planform in the form of a triangle. ... A supersonic transport (SST) is a civil aircraft designed to transport passengers at speeds greater than the speed of sound. ...

Experiments

A famous experiment involving laminar flow uses two concentric glass cylinders with the gap filled with glycerin. A drop of ink is placed in the fluid. When the outer cylinder is turned, the drop is drawn out into a thread that eventually becomes so thin that it disappears from view. At this point the ink molecules are said to be "enfolded" in the glycerin. If the cylinder is then turned in the opposite direction, the thread reforms and then becomes a drop. This experiment is typically used to show implicit order, but also nicely demonstrates the properties of laminar flow. Glycerin, also well known as glycerine and glycerol, and less commonly as 1,2,3-propanetriol, 1,2,3-trihydroxypropane, glyceritol, and glycyl alcohol is a colorless, odorless, hygroscopic, and sweet-tasting viscous liquid. ... Implicit order means a system has hidden information which is not apparent based solely on direct observation. ...

See also

• Couette flow
• Laminar flow cabinet
• Osborne Reynolds
• Poiseuille's law

The term Couette flow refers to the laminar flow of a viscous liquid in the space between two surfaces, one of which is moving relative to the other. ... UV light desinfects the sterile laminar flow cabinet when not in use Laminar flow cabinet or laminar flow closet is a carefully enclosed bench designed to prevent contamination of semiconductor wafers, biological samples, or any particle sensitive device. ... Osborne Reynolds Osborne Reynolds (23 August 1842–21 February 1912) was a British fluid dynamics engineer. ... The Poiseuilles law (or the Hagen-Poiseuille law also named after Gotthilf Heinrich Ludwig Hagen (1797-1884) for his experiments in 1839) is the physical law concerning the voluminal laminar stationary flow ΦV of incompressible uniform viscous liquid (so called Newtonian fluid) through a cylindrical tube with the constant...

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