Laminar flow

Laminar flow, also known as streamline flow, is a type of flow in which the fluid travels smoothly or in regular paths, in contrast to turbulent flow, in which the fluid undergoes irregular fluctuations and mixing. In laminar flow, the velocity, pressure, and other flow properties at each point in the fluid remain constant. Laminar flow occurs in fluids with a low Reynolds number, which is a dimensionless quantity that describes the nature of flow.

Characteristics

Laminar flow is characterized by high momentum diffusion and low momentum convection. When a fluid is flowing in a laminar manner, there are no cross-currents perpendicular to the direction of flow, nor eddies or swirls of fluids. In laminar flow, the motion of the particles of the fluid is very orderly with all particles moving in straight lines parallel to the pipe walls.

Applications

Laminar flow is desirable in some contexts, such as in the aerodynamics of an aircraft wing, where it reduces drag, or in engineering applications such as pipe flow, where it can reduce losses. In other contexts, such as heat transfer, turbulent flow can be more efficient.

Laminar flow in medicine

In the medical field, laminar flow is used in operating rooms to reduce the risk of airborne contamination. Laminar flow cabinets are used to exclude contaminants from sensitive processes in science, electronics and medicine.

See also

• Fluid dynamics
• Hagen–Poiseuille equation
• Navier–Stokes equations
• Stokes' law
• Turbulence

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  Laminar flow profile
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  Stokes sphere
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  Laminar flow
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  Experimental chamber for studying chemotaxis in response to laminar flow