Pressure drop doesn't depend on pipe material (laminar flow)

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Discussion Overview

The discussion centers on the pressure drop equation for laminar flow in pipes, specifically addressing why it does not include a parameter for the surface roughness of the pipe material, contrasting it with turbulent flow scenarios.

Discussion Character

  • Technical explanation, Conceptual clarification, Debate/contested

Main Points Raised

  • One participant questions the absence of a surface roughness parameter in the laminar flow pressure drop equation, suggesting a difference from turbulent flow.
  • Another participant asserts that the boundary layer velocity is zero, implying a specific condition related to laminar flow.
  • A subsequent reply reiterates the point about the boundary layer velocity being zero, with a clarification that it refers to wall velocity.
  • There is a mention of "slip," which introduces a potential condition that may affect the discussion.

Areas of Agreement / Disagreement

The discussion contains multiple viewpoints regarding the implications of boundary layer behavior in laminar flow, and it remains unresolved whether the absence of a surface roughness parameter is significant.

Contextual Notes

Participants have not fully explored the implications of "slip" or how it may relate to the pressure drop equation, leaving some assumptions unaddressed.

Mohamed_Wael
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why does the pressure drop equation derived for the laminar flow has no parameter to indicate the surface roughness of the material of the pipe,unlike the turbulent flow !
 
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Zero equals zero.
 
what do u mean ?
 
The boundary layer velocity is zero.
 
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Likes   Reactions: Mohamed_Wael
Bystander said:
The boundary layer velocity is zero.

I believe you mean the wall velocity is zero.
 
... barring "slip."
 

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