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Make Shortcut to Home Screen? Laminar, Transitional or Turbulent Flow When calculating heat transfer or pressure and head loss it is important to know if a fluid flow is laminar, transitional or turbulent Sponsored Links.
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This means that every time you visit this website you will need to enable or disable cookies again. What is Reynolds Number? Sign Up. Figure 1: A glass of water a at rest; b flows.
Fluid flow occurs due to imbalanced forces thus defining flow characteristics that the Reynolds number can quantify.
Figure 2: a Experimental setup established by Osborne Reynolds; b Experimental visualization of laminar and turbulent flow. Figure 3: Osborne Reynolds Figure 5: Transition of the boundary layer for flow over the flat plate surface with critical length for transition regime.
References Stokes, George. Transactions of the Cambridge Philosophical Society. Reynolds, Osborne. Philosophical Transactions of the Royal Society. Sommerfeld, Arnold. International Congress of Mathematicians, , P. White, Frank. Fluid Mechanics. Did this article solve your issue?
It is defined as:. The velocity profile in turbulent flow is flatter in the central part of the pipe i. The flow velocity drops rapidly extremely close to the walls. This is due to the diffusivity of the turbulent flow. In the case of turbulent pipe flow, there are many empirical velocity profiles. The simplest and the best known is the power-law velocity profile :. This dependency is empirical, and it is shown in the picture.
In short, the value n increases with increasing Reynolds number. The one-seventh power-law velocity profile approximates many industrial flows. The configuration of the internal flow e. In general, this flow regime is important in engineering because circular pipes can withstand high pressures and hence convey liquids. Non-circular ducts are used to transport low-pressure gases, such as air in cooling and heating systems. For the internal flow regime , an entrance region is typical.
In this region, a nearly inviscid upstream flow converges and enters the tube. The hydrodynamic entrance length is introduced to characterize this region and is approximately equal to:.
This is the longest development length possible. In turbulent flow , the boundary layers grow faster, and L e is relatively shorter. The entrance effects may be neglected at a finite distance from the entrance because the boundary layers merge and the inviscid core disappears.
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