Friction in Pipelines (as headloss)

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SUMMARY

The discussion centers on the concept of headloss in pipelines, specifically addressing the role of viscosity as the primary contributor to this phenomenon. It clarifies that traditional terminology around "friction" is misleading, as the losses are primarily due to shear within the fluid rather than wall friction. The Darcy-Weisbach, Manning, and Hazen-Williams equations are highlighted as key methods for calculating headloss. The conversation emphasizes the distinction between viscous losses and traditional frictional losses, noting that wall roughness contributes to increased energy requirements through the generation of eddies.

PREREQUISITES
  • Understanding of Darcy-Weisbach equation for headloss calculation
  • Familiarity with Manning's equation for open channel flow
  • Knowledge of Hazen-Williams equation for water flow in pipes
  • Basic principles of fluid dynamics, particularly viscosity and shear stress
NEXT STEPS
  • Research the application of the Darcy-Weisbach equation in various pipeline scenarios
  • Explore the effects of wall roughness on fluid flow and energy loss
  • Study the relationship between viscosity and shear stress in fluid dynamics
  • Investigate transient flow conditions and their impact on headloss in pipelines
USEFUL FOR

Engineers, fluid dynamics researchers, and professionals involved in pipeline design and analysis will benefit from this discussion, particularly those focused on optimizing fluid flow and minimizing headloss in systems.

Mikealvarado100
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When we talk about headloss in pipelines (which is defined with Darcy-Weisbach or manning or hazen-Williams equations) we talk about friction between liquid and pipe wall and we do not talk about moving molecules of water on each other. Does not it (moving liquid surfaces on each other)result friction in fluid as headloss? This phenomenon can affect both on headloss in steady state condition and transient condition.
Would anyone explain about?

Thanx in advance.
 
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What you are essential describing is viscosity, and yes, it is the primary contributor to head loss. It honestly annoys me that so many texts talk about "friction" because it isn't friction in the traditional sense, but viscous losses are similar enough to frictional losses that this has become common terminology.
 
Last edited:
The component of viscosity induced head losses due to wall friction is zero. The layer of fluid touching the wall is at zero velocity. There is no wall friction. All losses are caused by shear in the fluid. What wall roughness does is generate eddies in the fluid thus increasing the work needed.
 

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