(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

Medium lubricating oil, of specific gravity 0.860, is pumped through 300 m of horizontal 50-mm-diameter pipe at the rate of 0.00114 m3/s. If the drop in the pressure is 200 kPa, the absolute viscosity of the oil in N×s/m2 is...____________?

specific gravity (SG) = 0.86

length (l) = 300 m

diameter (d) = .05 m

flow rate (Q) = 0.00114 m^3/s

Pressure drop (P) = 200E3 Pa

2. Relevant equations

I know that:

shear stress (t) = viscosity (mu) * velocity gradient

where:

velocity gradient = (change in velocity) / (change in height)

3. The attempt at a solution

I'm not quite sure how to begin with this. I have a solution from my prof. (this is a question on a sample/practice exam for our final)... but I have NO clue where he's coming up with this equation:

P = 32 * (mu) & (l) * [(v)/(.05m)^2]

Where on Earth does the 32 come from? What significance does the (.05m)^2 have... without pi/4 anyway? Can anyone make any sense of this? The solution is supposed to be... approximately 0.09 (N s) / (m)^2. Let me know if anybody has any ideas.

Thanks,

~~Chad~~

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# Homework Help: Fluid Mechanics of oil

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