Finding the Darcy-Weisbach Friction Factor with Limited Info

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SUMMARY

The discussion centers on calculating the Darcy-Weisbach friction factor using limited information, specifically when the Reynolds number is unknown. The user, Ben, has provided parameters including a roughness height (K = 0.02 mm), pipe diameter (D = 150 mm), and flow rate (Q = 100 l/s). To find the Reynolds number, the formula RE = (density) x (velocity) x (diameter of pipe) / (dynamic viscosity) is suggested, but the fluid type remains unspecified. Participants recommend assuming fully developed turbulent flow to proceed with the calculation.

PREREQUISITES
  • Understanding of fluid dynamics principles
  • Familiarity with the Darcy-Weisbach equation
  • Knowledge of the Moody diagram for friction factor determination
  • Basic fluid properties such as density and dynamic viscosity
NEXT STEPS
  • Research how to calculate Reynolds number for various fluids
  • Study the Moody diagram and its application in calculating friction factors
  • Learn about fully developed turbulent flow characteristics
  • Explore methods for estimating fluid properties when not provided
USEFUL FOR

Engineering students, fluid mechanics practitioners, and anyone involved in hydraulic system design or analysis will benefit from this discussion.

ben49
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Homework Statement


I need to find the Darcy Weibach friction factor from the moody diagram but i cannot find reynolds number?

All the information i have is K = 0.02mm D = 150mm Q=100 l/s

The only formula for RE i found is RE = (density) x (velocity) x (diameter of pipe) / (dynamic viscocity)

Im really stuck.

Any help would be much appreciated.

Thanks

Ben


Homework Equations





The Attempt at a Solution

 
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Did the problem statement tell you what the fluid is (e.g oil, water)?
 
No it didnt?
 
You may need to assume fully developed turbulent flow then. What is the pipe material (e.g. steel, PVC)?
 

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