Thanks Chris, good advice.
Cheers,
Robin
>
> On Aug 4, 2005, at 8:10 AM, Pankaj Mandal wrote:
>
> > I have seen these pipes and truely speaking these ripples are too
> > smooth to increase friction co-efficient. Best conservative
> > approximation would be to redo the calculation with a reduced pipe
> > inside diameter (Pipe OD - 2* wall thickness at the ripples) for the
> > entire pipelength keeping the same friction factor and compare the
> > results.
> Or adjust the hydraulic diameter (=4(cross-sectional area)/(wetted
> perimeter)) to include the actual geometry. Unless the fabrication is
> really squirrelly it won't make any practical difference. The data used
> to generate friction coefficients scatters all over the place, and your
> correction will probably fall inside the scatter band anyway.
>
> If the 'ripples' are big enough to affect the hydraulics, they're
> probably big enough to affect the structural response. Make sure that
> the pipe dimensions comply with the requirements of your specific
> piping code and the applicable ASTM spec. You may not have a problem
> with everything new and uncorroded, but pipe never improves with time
> or repairs itself or gets accustomed to overload.
> Christopher Wright P.E. |"They couldn't hit an elephant at
> chrisw@skypoint.com | this distance" (last words of Gen.
> .......................................| John Sedgwick, Spotsylvania
> 1864)
> <a href="http://www.skypoint.com/~chrisw/">http://www.skypoint.com/~chrisw/</a>
>
>
>
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Received on Sat Aug 06 04:58:00 2005
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