As you havewill learn the friction factor is an extremely im

As you have/will learn, the friction factor is an extremely important variable that engineers must consider when designing fluid systems. If you’re a civil engineer, who’s passed the FE exam looking for the friction factor, you might consider using Hazen Williams or Darcy Weisbach equation to determine the friction factor. List the pro’s and con’s as to which one might be the most appropriate to determine f. Which would you like is used most often? Which is the most accurate?

Solution

Darcy Weisbach was deduced experimentally at a time when the existing piping or cast iron were relatively short lengths between joints, with walls and joints irregular. Thus the flow regime was generally in TURBULENT ZONE, then the curve fitting formulas that were used at that time was very good for this regime where f is a constant .

The Darcy Weisbach equation was difficult to use because the friction factor was difficult to estimate on the other hand Hazen and Williams provided an empirical formula that was easy to use.

However the hazen william  formula does not take into consideration different viscosities of liquids like the Darcy-Weisbach formula does during the calculation of the Reynolds Number. The Hazen-Williams formula uses a pipe roughness coefficient called the C factor only. The C factor is a measure of the roughness of the pipe internal wall.

hazen william  formula is used often.

the Darcy-Weisbach formula is more accurate.