{"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":"<p>Hi all,&nbsp;<\/p>\n<p>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<p>*** AQWA Eigenvalue: 3.77 sec<\/p>\n<p><a class=\"wp-colorbox-image cboxElement\" href=\"\/forum\/wp-content\/uploads\/sites\/2\/2023\/07\/03-07-2023-1688419411-mceclip1.png\"><img decoding=\"async\" src=\"\/forum\/wp-content\/uploads\/sites\/2\/2023\/07\/03-07-2023-1688419411-mceclip1.png\"><\/a><\/p>\n<p>*** AQWA Free Decay: 4.04 sec (below is my setting):<\/p>\n<p><a class=\"wp-colorbox-image cboxElement\" href=\"\/forum\/wp-content\/uploads\/sites\/2\/2023\/07\/03-07-2023-1688419324-mceclip0.png\"><img decoding=\"async\" src=\"\/forum\/wp-content\/uploads\/sites\/2\/2023\/07\/03-07-2023-1688419324-mceclip0.png\"><\/a><\/p>\n<p>*** My eigenvalue calculation with added mass &amp; critical damping coefficient from the .LIS file from RAO Calculation: 4.78 sec<\/p>\n<p>&nbsp;<\/p>\n<p>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.&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>Thank you!<\/p>\n<p>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":[],"acf":[],"custom_fields":[{"0":{"_bbp_subscription":["244837","183765"],"_bbp_author_ip":["23.206.193.146"]," _bbp_last_reply_id":["0"]," _bbp_likes_count":["0"],"_btv_view_count":["1492"],"_edit_lock":["1688589215:170252"],"_bbp_likes_count":["1"],"_bbp_topic_status":["unanswered"],"_bbp_status":["publish"],"_bbp_topic_id":["291367"],"_bbp_forum_id":["27791"],"_bbp_engagement":["183765","244837"],"_bbp_voice_count":["2"],"_bbp_reply_count":["3"],"_bbp_last_reply_id":["291823"],"_bbp_last_active_id":["291823"],"_bbp_last_active_time":["2023-07-06 09:26:41"],"_bbp_notification_enabled":["150512"]},"test":"riyanto-rnortheastern-edu"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/291367","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics"}],"about":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/types\/topic"}],"version-history":[{"count":0,"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/291367\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=291367"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}