Dear members,
A problem has come up about the vibration of a 48", 600# LNG export pipeline and a connected 24" line near the pig launcher . It has been found that if the flow rate is increased, there is severe vibration on this branch line, and it is reduced if the flow rates decrease. How to simulate this kind of problem of flow induced vibration in Caesar-II.

The compressor driving the flow is about 200m away and is connected to this system by underground lines. Therefore, I think the transmission of the compressor induced vibration is not a contributing factor towards the vibration problem.
Rahman
urahaman@tebodin.co.om

Usiur,

First: CAESAR II is not the software to look for possible causes of flow induced vibration. BOS Fluids from Paulin Research Group can be the software for you. CAESAR II can be used for your assistance to minimize the problem in the following way:

1) Go for field readings and observe the shape of vibration in your sysyem. By shape of vibration I mean the portions of your system which are vibrating the most i.e. where the peak to peak displacement/ velocity recordings are high. Now go through the modal analysis report of CAESAR II and observe which mode shape best simulates the actual reading at site.Restructure the supporting arrangement and may be support types also to eleminate those modes shape(s).

This can be the only way to get help from CAESAR II to solve this problem.

Anindya Bhattacharya

Also, if you use the [Search] option above, and search for the work "harmonic", a number of previous posts are found on this subject. Specifically this one , which addresses the same problem.