laminar flow: Definition and Much More from Answers.com
- ️Wed Jul 01 2015
n.
Nonturbulent flow of a viscous fluid in layers near a boundary, as that of lubricating oil in bearings.
A smooth, streamline type of viscous fluid motion characteristic of flow at low-to-moderate deformation rates. The name derives from the fluid's moving in orderly layers or laminae.
The chief criterion for laminar flow is a relatively small value for the Reynolds number, Re = ρVL/μ, where ρ is fluid density, V is flow velocity, L is body size, and μ is fluid viscosity. Laminar flow may be achieved in many ways: low-density flows as in rarefied gases; low-velocity or “creeping” motions; small-size bodies such as microorganisms swimming in the ocean; or high-viscosity fluids such as lubricating oils. At higher values of the Reynolds number, the flow becomes disorderly or turbulent, with many small eddies, random fluctuations, and streamlines intertwining. See also Creeping flow; Reynolds number; Turbulent flow; Viscosity.
Nearly all of the many known exact solutions of the equations of motion of a viscous fluid are for the case of laminar flow. These mathematically accurate descriptions can be used to give insight into the more complex turbulent and transitional flow patterns for which no exact analyses are known. See also Navier-Stokes equation.
The theory of viscous lubricating fluids in bearings is a highly developed area of laminar flow analysis. Even large Reynolds number flows, such as aircraft in flight, have regions of laminar flow near their leading edges, so that laminar flow analysis can be useful in a variety of practical and scientifically relevant flows. See also Antifriction bearing; Boundary-layer flow; Fluid flow; Lubricant.
A type of non- turbulent flow where the movement of each part of the fluid (gaseous, liquid, or plastic) has the same velocity, with no mixing between adjacent ‘layers’ of the fluid. It may be seen at low velocities in a smooth, straight river channel, and at some glacier snouts. Compare with turbulent flow.
Fluid flow in which the fluid travels smoothly or in regular paths. The velocity, pressure, and other flow properties at each point in the fluid remain constant. Laminar flow over a horizontal surface may be thought of as consisting of thin layers, all parallel to each other, that slide over each other. It is common only where the flow channel is relatively small, the fluid is moving slowly, and its viscosity is relatively high. Examples include the flow of oil through a thin tube and blood flow through capillaries. See also turbulent flow.
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fluid flow; streamline flow
The smooth flow of a fluid in which adjoining layers of the fluid flow parallel to one another. During laminar flow, all the fluid particles move in distinct and separate layers; there is no mixing between adjacent layers. Compare turbulent flow.
Laminar flow
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, pressure and velocity independent from time. It is the opposite of turbulent flow. In nonscientific terms laminar flow is "smooth," while turbulent flow is "rough."
The dimensionless Reynolds number is an important parameter in the equations that describe whether flow conditions lead to laminar or turbulent flow. Reynolds numbers of less than 2100 are generally considered to be of a laminar type. When the Reynolds number is much less than 1, Creeping motion or Stokes flow occurs. This is an extreme case of laminar flow where viscous (friction) effects are much greater than inertial 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.
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