Hi everyone..
My structure is an FPSO which is having a cylindrical part with a bottom opening (turret).What I want to do is to raise the water surface inside the cylinder w.r.t to the mean water level outside the structure so that the water surface inside the cylinder should produce a decaying sine shaped curve due to gravity and buoyancy effects.I have attached an image.Please check it. Can anybody help me on this? Any Star CCM+ experts?
Thanks in advance.
What do you mean by FPSO?
Do you use a VOF multiphase model?
Thank you Madam for your reply....
Floating,Production,Storage and Offloading (FPSO) is a ship shaped offshore structure.....Further details you can can check..
https://en.wikipedia.org/wiki/Floating_production_storage_and_offloading
It will be towed to the location(offshore) during which it has to encounter waves creating oscillations inside the cylinder......
Yes....free surface is modeled using VOF model.......
You can use field function to define a initial vof profile based on centroid0].
It will looks like the following:
centroid[0]b? vofflatwave:waterinside)
where vofflatwave is the volume fraction of water of your free surface while waterinside is the volume fraction of water of your water level inside your moonpool.
Do not forget to define the volume fraction for your air by the same method.
Best Regards
Saishuai
Hi Saishuai.....
......I was able to raise the water surface inside the cylinder using field functions as above...What troubles me now is that the graph obtained is not of the proper shape as I expected...I was monitoring the motion (in the z direction) of a particular point on the free surface inside the cylinder...Am I doing it correct...?
Thank you Saishuai for your interest and help
Sorry for the late response, have you figure out the problem?
First of all, how did you monitor the motion? What kind of probe did you use?
Hi Saishuai....
Yes...using field functions I was able to raise the water level.....I am not using any probe....I created a point using the intersection of water surface(iso) and 2 other plane sections....Then I monitored the motion of that point in x,y and z directions of a local coordinate system placed at the center of cylinder....
Hi Hariharan
what you have done seems correct to me. There might be several issues that you need to pay attention to
I assume that you have wave.
1) Time step size and mesh size are very important for simulation concerned with wave. It is recommend to use second order time solver and make sure the maximun CFL in the region that you are interested in is small than 0.5.
2) you may get elevation that is not of perfect sine shape which is correct since moonpool motion is not a piston motion. There is spatial variation due to pressure distribution effect.
Hope you can solve this soon, otherwise I can have a look at your case if you can send me you sim file.
Best Regards
Saishuai
Hi Saishuai...
I got the result..!!! Error was due to my improper meshing...Thank you for your support..Hope I am not late to inform you...
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