A person with no experience in fluid mechanics wants to estimate the friction factor for 2.5-cm-...

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A person with no experience in fluid mechanics wants to estimate the friction factor for 2.5-cm- diameter galvanized iron pipe (with equivalent roughness = 0.15 mm) at a Reynolds number of 8,000. He stumbles across the simple equation f = 64/Re and uses this to calculate the friction factor. (a) Explain the problem with this approach. (b) Now use the Moody chart (given above) to determine the friction factor. Also compare the result with the prediction of the Haaland equation --1.8log (1) 3.7 (c) Estimate the error of the inexperienced person. 1.11 Re 0.1 0.09 0.08 0.07 0.06 0.05 0.04 0.03 0.025 0.02 0.015 Laminar flow Wholly turbulent flow Smooth Transition range 0.01 0.009 0.008 2(10) 4 68 10 10 5 0.05 0.04 0.03 0.02 0.015 0.01 0.008 0.006 0.004 D 0.002 0.001 0.0008 0.0006 0.0004 0.0002 0.0001 0.00005 2(10) 468 2(10) 468 2010 A 68 2(10) 0.00001 4 68 10 10 10 Re-PVD " A person with no experience in fluid mechanics wants to estimate the friction factor for 2.5-cm- diameter galvanized iron pipe (with equivalent roughness = 0.15 mm) at a Reynolds number of 8,000. He stumbles across the simple equation f = 64/Re and uses this to calculate the friction factor. (a) Explain the problem with this approach. (b) Now use the Moody chart (given above) to determine the friction factor. Also compare the result with the prediction of the Haaland equation --1.8log (1) 3.7 (c) Estimate the error of the inexperienced person. 1.11 Re 0.1 0.09 0.08 0.07 0.06 0.05 0.04 0.03 0.025 0.02 0.015 Laminar flow Wholly turbulent flow Smooth Transition range 0.01 0.009 0.008 2(10) 4 68 10 10 5 0.05 0.04 0.03 0.02 0.015 0.01 0.008 0.006 0.004 D 0.002 0.001 0.0008 0.0006 0.0004 0.0002 0.0001 0.00005 2(10) 468 2(10) 468 2010 A 68 2(10) 0.00001 4 68 10 10 10 Re-PVD "