Why does friction factor decrease with Reynolds number?

Thread starter Ram7788
Start date Mar 8, 2016
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decrease Fluid dynamics Friction Friction factor Reynolds Reynolds number

In summary, friction factor is an important factor in fluid dynamics as it measures the resistance to flow caused by surface roughness and is used to determine pressure drop in a fluid system. The relationship between friction factor and Reynolds number is inverse, with higher Reynolds numbers resulting in lower friction factors due to increased turbulence. This leads to a more efficient and smoother fluid flow with less energy loss. The decrease in friction factor with increasing Reynolds number also allows for the use of smoother pipes in pipe design, resulting in cost savings and more efficient fluid flow.

Mar 8, 2016

Ram7788

As the flow rate increases frictional force increases but friction factor(Darcy,Fanning) decreases with Re. Can anyone explain what is the concept behind it?

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Mar 10, 2016

gracy

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1. Why is friction factor important in fluid dynamics?

Friction factor is important in fluid dynamics because it is a measure of the resistance to flow caused by the surface roughness of a pipe or channel. It is used to determine the pressure drop in a fluid system, which is crucial for designing efficient and cost-effective piping systems.

2. What is the relationship between friction factor and Reynolds number?

The relationship between friction factor and Reynolds number is inverse. As Reynolds number increases, the friction factor decreases. This is because at higher Reynolds numbers, the flow becomes more turbulent, reducing the effect of surface roughness on the flow resistance.

3. How does the decrease in friction factor with Reynolds number affect fluid flow?

The decrease in friction factor with Reynolds number leads to a more efficient and smoother fluid flow. This means that for the same flow rate, a higher Reynolds number will result in a lower pressure drop and less energy loss in the system.

4. Why does friction factor decrease with increasing Reynolds number?

Friction factor decreases with increasing Reynolds number because at higher Reynolds numbers, the flow becomes more turbulent. Turbulent flow is less affected by surface roughness compared to laminar flow, resulting in a lower friction factor.

5. How does the decrease in friction factor with Reynolds number affect pipe design?

The decrease in friction factor with Reynolds number affects pipe design by allowing for the use of smoother pipes with lower surface roughness. This can result in cost savings in pipe construction, as well as more efficient fluid flow with lower pressure drops and energy losses.