{"id":291367,"date":"2023-07-03T21:28:26","date_gmt":"2023-07-03T21:28:26","guid":{"rendered":"\/forum\/forums\/topic\/aqwa-eigenvalue-vs-free-decay-test-resulting-in-different-heave-natural-period\/"},"modified":"2023-07-05T20:34:06","modified_gmt":"2023-07-05T20:34:06","slug":"aqwa-eigenvalue-vs-free-decay-test-resulting-in-different-heave-natural-period","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/aqwa-eigenvalue-vs-free-decay-test-resulting-in-different-heave-natural-period\/","title":{"rendered":"AQWA Eigenvalue vs Free Decay Test Resulting in Different Heave Natural Period?"},"content":{"rendered":"

Hi all, <\/p>\n

I am trying to find the heave natural period of a simple cone using the AQWA Eigenvalue module and a free decay test. I also calculated that manually so that I could confirm that the results were matching. However, the results are all different:<\/p>\n

*** AQWA Eigenvalue: 3.77 sec<\/p>\n

<\/a><\/p>\n

*** AQWA Free Decay: 4.04 sec (below is my setting):<\/p>\n

<\/a><\/p>\n

*** My eigenvalue calculation with added mass & critical damping coefficient from the .LIS file from RAO Calculation: 4.78 sec<\/p>\n

 <\/p>\n

Do you have any tips on how I can get the calculation correct? Or were any settings that I should have calculated the natural period accurately? I believe my analysis (4.78 sec), but I fear it will not be reflected in the model and would interfere with the seastate peak period I would put into the structure. <\/p>\n

 <\/p>\n

Thank you!<\/p>\n

Danu Riyanto<\/p>\n","protected":false},"template":"","class_list":["post-291367","topic","type-topic","status-closed","hentry","topic-tag-ansys-aqwa","topic-tag-ansysaqwa","topic-tag-aqwa","topic-tag-eigenvalue","topic-tag-hydrodynamic"],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t