On Oct 3, 2005, at 4:34 AM, Steve McKenzie wrote:
> Question 1: does anyone have a reputable calculation reference for
> the natural (slosh) frequency of a rectangular tank with known
> dimensions, fill depth fluid density and viscosity?
The classic calculation is by Housner 'Dynamic Pressures on Accelerated
Fluid containers,' Bulletin Seismological Society of America, 47(1)
Jan 57. I expect it's been re-printed in a dozen different textbooks
and references. Mine is _Nuclear Reactors and Earthquakes_ US Atomic
Energy Commission TID-7024, which you may be able to get. Otherwise try
to Google out G. W. Housner.
> It appears to me that unless the vibration spectrum is
> known, it is not possible to calculate the stresses in the tank walls.
I think those accelerations you have are the spectral accelerations. A
ground acceleration greater than 1 G would destroy everything totally.
A magnitude 8 quake only has epicentral accelerations of 1-2 g. I think
what you need to do is figure the structural frequencies and apply the
given accelerations as if they were static loads. Even those are very
high for spectral accelerations. I got a set of response spectra for
Taiwan with peak values up around 12G, and I think someone is
worst-casing himself into an early grave. A 2g ZPA would destroy the
island. None of the half-dozen or so survivors would give a damn if an
oil tank were the only thing left standing on the whole island. But
that's what they claim they wanted…
Christopher Wright P.E. |"They couldn't hit an elephant at <a href="/group/PipingDesign/post?postID=Cbqs-MjpoQBBpVX3GUcZJN7owXJCiGM3dL5IfEmy-8Xr22XBq1C_VfmUZyg6GfvwIc1zU7N1dLJfZN8">chrisw@skypoint.com</a> | this distance" (last words of Gen.
.......................................| John Sedgwick, Spotsylvania1864)
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