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bobo5195 · 03-23-2006, 11:36 PM

For this exact reason that more accurate curve fitting is not better.

The x^7 correlation is wrong flow does not vary like that. Swiftechs results have errors and variances fitting in all the things they got wrong is not making things better. Flow correlations are not a many term polynomial! More likely to be a power law result but even then beware and be prepared to use voodoo magic.

Most stuff should correspond to a x^2 correlation only. So dp = a * flow^2.

Have a google for “hazen williams” and the “moody diagram” and its corelations to see slightly different equations to fit to.

03-23-2006, 11:36 PM	#16
bobo5195 Cooling Savant Join Date: Aug 2005 Location: uk Posts: 400	Re: Units Converter & Equation Solver For this exact reason that more accurate curve fitting is not better. The x^7 correlation is wrong flow does not vary like that. Swiftechs results have errors and variances fitting in all the things they got wrong is not making things better. Flow correlations are not a many term polynomial! More likely to be a power law result but even then beware and be prepared to use voodoo magic. Most stuff should correspond to a x^2 correlation only. So dp = a * flow^2. Have a google for “hazen williams” and the “moody diagram” and its corelations to see slightly different equations to fit to.