Laminar flow

Laminar flow is characterized by the smooth flow of a liquid. This tends to happen at low velocities when there are few disturbances, such as in a straight, smooth pipe. In laminar flow through a pipe, it is assumed that the velocity of the fluid is zero at the boundaries of the pipe and is at a maximum in the center; mathematically, the velocity profile is parabolic. Microscopically, the particles or pieces of the liquid flow in a straight line along the direction of the pipe and do not mix with other layers of fluid. The layers slide past one another like playing cards. This is in contrast to turbulent flow, when a fluid swirls around.

Even though there is no mixing, there is still some friction in the flow. This friction will cause a pressure drop and its numerical value is given by the Hagen-Poiseuille equation.

Laminar Flow Media

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  The velocity profile associated with laminar flow resembles a deck of cards. This flow profile of a fluid in a pipe shows that the fluid acts in layers that slide over one another.

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  A sphere in Stokes flow, at very low Reynolds number. An object moving through a fluid experiences a drag force in the direction opposite to its motion.

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  In the case of a moving plate in a liquid, it is found that there is a layer (lamina) that moves with the plate, and a layer of stationary liquid next to any stationary plate.

• Experimental chamber for studying chemotaxis in response to laminar flow.