Pipeline Stability - Effect of Wave Period
Pipeline Stability - Effect of Wave Period
(OP)
When analyzing pipeline stability using morisons equations, the stability generally decreases as the wave period is increased. Is this due to to a longer period carrying a larger volume of water and hence generating a larger force on the pipeline? As I would assume that a lower period would also generate larger velocities which would decrease stability? Are either of these correct or is it not this simple? Any advice appreciated.





RE: Pipeline Stability - Effect of Wave Period
Shorter period = faster velocities, but for a shorter duration. You also get more impulses during any given time.
The overall response you get is dependent on two relationships
1.) the ratio of the pipeline's natural frequency to the wave period, basically responsible for larger deflection amplitudes, as those forces are sustained for longer times, larger deflection movements can be produced, but at lower frequencies.
2.) the ratio of the pipeline's natural frequency to the vortex shedding frequency generated by the drag of the water flowing around the pipeline, but usually at higher frequencies and primarily responsible for higher vibration modes.
You want to try to keep the pipeline's natural resonance frequency outside the affecting range of both of those and perhaps some of the prime harmonics of those frequencies as well.
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RE: Pipeline Stability - Effect of Wave Period
RE: Pipeline Stability - Effect of Wave Period
We are more connected to everyone in the world than we've ever been before, except to the person sitting next to us. Lisa Gansky