Pipe flow
Internal flow within closed conduits, lacking a free surface.
Pipe flow is a type of fluid flow within a closed conduit, such as a pipe, duct, or tube, also referred to as internal flow. It is distinguished from open-channel flow by the absence of a free surface, and it exerts hydraulic pressure on the conduit rather than direct atmospheric pressure.
- field
- Fluid mechanics
- known_for
- Internal flow within closed conduits, governed by viscosity and gravity relative to inertial forces
- energy_expression
- Head, defined by the Bernoulli equation
- friction_loss_formula
- Darcy-Weisbach formula
Lore & Background
Pipe flow is a fundamental concept in fluid mechanics, describing the behavior of fluids moving through closed conduits such as pipes, ducts, or tubes. It is also called internal flow, in contrast to open-channel flow, which has a free surface exposed to atmospheric pressure. Pipe flow does not have a free surface and exerts hydraulic pressure on the conduit walls. Not all flow within a closed conduit is considered pipe flow; for example, storm sewers usually maintain a free surface and are classified as open-channel flow, unless they operate at full capacity.
Reader's Guide
The significance of pipe flow lies in its widespread application in engineering systems, from water supply networks to industrial pipelines. Energy in pipe flow is expressed as head and defined by the Bernoulli equation, with frictional losses described by the Darcy-Weisbach formula. The behavior of pipe flow is governed by viscosity and gravity relative to inertial forces, characterized by the Reynolds number. Non-circular pipes have a shifted critical Reynolds number, typically on the order of 10^3, while special geometries like the Tesla valve can cause transition at Reynolds numbers as low as 10^2. Understanding pipe flow is essential for designing efficient fluid transport systems and predicting pressure losses.
Did You Know?
- Pipe flow does not have a free surface, unlike open-channel flow.
- Storm sewers are considered open-channel flow unless they operate at full capacity.
- The Darcy-Weisbach formula defines frictional losses in pipe flow.
More in Classical And Fluid Mechanics 1-19
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