Verification Case 11
PRODUCT: AFT Fathom
TITLE: FthVerify11.fth
REFERENCE: Ernest Brater, Horace Williams, James Lindell, C.Y. Wei, Handbook of Hydraulics, 7th Ed., 1996, McGraw-Hill, Page 13.14, Example 13.9, results on page 13.39
FLUID: Water
ASSUMPTIONS: Temperature unspecified, so assume 20 deg. C
RESULTS:
| Pipe Flow Rate (m3/s) | 1 | 2 | 3 | 4 | 5 | 6 |
| Handbook | 3.42 | 2.68 | 0.89 | 3.21 | 3.21 | 1.79 |
| AFT Fathom | 3.48 | 2.73 | 0.94 | 3.21 | 3.21 | 1.79 |
| Node EGL (m) | 1 | 2 | 3 | 4 | 5 |
| Handbook | 11.42 | 10.00 | 9.37 | 10.06 | 8.32 |
| AFT Fathom | 11.46 | 10.00 | 9.38 | 10.06 | 8.33 |
DISCUSSION:
The Handbook of Hydraulics solves the network using a different method than AFT Fathom, and also uses slightly different friction laws. The head loss relationship in the handbook assumes that the head loss in each pipe varies as the flow rate to the 1.85 power. AFT Fathom assumes it varies by the 2nd power. This slight difference accounts for the slightly different results.
Results for AFT Fathom vary somewhat from previous versions of AFT Fathom (prior to version 7) because the equation used to convert the Hazen-Williams factor to the Darcy-Weisbach friction factor was modified to use the traditional formula, as given in the AFT Fathom Help File.
