Re: Impressed vibration

>I would like to investigate the impressed frequency caused due to the flow
>and compare it with the natural frequency of the system.
I'd be interested in what the 'impressed frequency' is actually impressed by. Presumably the impressed frequency is what I know of as 'forcing frequency' but I've never heard of an internal flow producing cyclic loading all by itself. Things like valve closing dynamics or possibly vortex shedding or something of the sort. Turbulence is substantially random, and won't excite a resonance to a great degree.

You can estimate frequencies of a single run of piping manually, but to determine the actual displacement and stress response you need to be able to decide on the loading. I've never used Caesar, but if there's a harmonic response, you'll need to use it before the frequencies will do you any good. If you've never done any structural dynamics, you should do some homework on the topic first. It's not particularly intuitive for for most dynamic loading requires a careful hand at the tiller to validate results.

Christopher Wright P.E.    |"They couldn't hit an elephant at
chrisw@skypoint.com        | this distance"   (last words of Gen.
___________________________| John Sedgwick, Spotsylvania 1864)