{"id":350816,"date":"2024-02-12T14:04:00","date_gmt":"2024-02-12T14:04:00","guid":{"rendered":"\/forum\/forums\/topic\/validation-of-aqwa-using-morison-elements\/"},"modified":"2024-02-12T14:04:00","modified_gmt":"2024-02-12T14:04:00","slug":"validation-of-aqwa-using-morison-elements","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/validation-of-aqwa-using-morison-elements\/","title":{"rendered":"Validation of AQWA using Morison elements"},"content":{"rendered":"<p>Hi Everyone,<br \/>I am trying to validate the results from Ansys AQWA with the Morison&#8217;s equation for a fixed monopile. But I have some questions with the outputs from AQWA.<\/p>\n<p>Problem description: A monopile fixed on the seabed. Aim &#8211; To determine the wave forces on the monopile.<br \/>D = 3.048m (diameter of the monopile)<br \/>d = 152.4m (water depth)<br \/>L = 156.1310m (wavelength)<br \/>H = 3.048m (wave height)<br \/>T = 10s (Time period)<\/p>\n<p>With these parameters it can be deduced that the Airy theory is applicable and deep water conditions also apply (as d\/L&gt;0.5). By checking the force regime from the chart (https:\/\/doi.org\/10.1016\/j.renene.2013.08.041) the problem falls under region III where there is large inertia and small drag which indicates the use of the Full Morison&#8217;s equation.<\/p>\n<p>Ansys AQWA setup &#8211; I have used beam elements with a hollow circular cross section to represent the Morison elements. I have done both frequency domain and time domain analysis. In the line body options in the geometry tree, I have selected the option &#8216;Structure is free to move&#8217; as it showed some errors while running the frequency domain simulations. In the time-domain simulations, I have introduced a regular wave with direction=0deg, Amplitude = 1.524m, Period =10s. I have also added deactivated freedoms in all 6DoFs to mimic that the structure is fixed and does not move. [I have attached few snips of the setup in AQWA in order of the setup itself]<\/p>\n<p>Results: I have attached an image with the plots comparing the results from analytically solving the Morison equation and by using AQWA. And it can be noted that there is a mismatch in the inertial component but the drag and total forces seem to be alright.<\/p>\n<p>Questions: So my questions are<br \/>1. When I performed the time domain analysis, apart from having drag and inertial forces, there is also a component of Froude-Krylov forces which doesn&#8217;t make sense as this is a pure Morison type problem. and this is the reason why the total forces match but the inertial forces do not.<\/p>\n<p>2. So does this say that my simulation setup in AQWA is incorrect or Am I interpreting the Froude-Krylov forces incorrectly.<\/p>\n<p>It would be great if someone can help out with this!<\/p>\n<p>Thanks!<\/p>\n<p><img decoding=\"async\" title=\"results\" src=\"\/forum\/wp-content\/uploads\/sites\/2\/2024\/02\/12-02-2024-1707746466-Result comparison.PNG\" alt=\"\"><\/p>\n<p><img decoding=\"async\" title=\"setup\" src=\"\/forum\/wp-content\/uploads\/sites\/2\/2024\/02\/12-02-2024-1707746430-aqwa1.PNG\" alt=\"\"><\/p>\n<p><img decoding=\"async\" title=\"diffraction setup\" src=\"\/forum\/wp-content\/uploads\/sites\/2\/2024\/02\/12-02-2024-1707746537-aqwa3.PNG\" alt=\"\"><\/p>\n<p><img decoding=\"async\" title=\"response\" src=\"\/forum\/wp-content\/uploads\/sites\/2\/2024\/02\/12-02-2024-1707746566-aqwa4.PNG\" alt=\"\"><\/p>\n<p><img decoding=\"async\" title=\"deactivated freedoms\" src=\"\/forum\/wp-content\/uploads\/sites\/2\/2024\/02\/12-02-2024-1707746594-aqwa5.PNG\" alt=\"\"><\/p>\n<p><img decoding=\"async\" title=\"Froude Krylov forces\" src=\"\/forum\/wp-content\/uploads\/sites\/2\/2024\/02\/12-02-2024-1707746623-aqwa7.PNG\" alt=\"\"><\/p>\n","protected":false},"template":"","class_list":["post-350816","topic","type-topic","status-closed","hentry"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_bbp_subscription":["61960","180344"],"_bbp_author_ip":["96.7.218.223"]," _bbp_last_reply_id":["0"]," _bbp_likes_count":["0"],"_btv_view_count":["1116"],"_bbp_topic_status":["unanswered"],"_bbp_likes_count":["1"],"_bbp_topic_id":["350816"],"_bbp_forum_id":["27792"],"_bbp_engagement":["61960","180344"],"_bbp_voice_count":["2"],"_bbp_reply_count":["7"],"_bbp_last_reply_id":["351888"],"_bbp_last_active_id":["351888"],"_bbp_last_active_time":["2024-02-16 10:29:29"]},"test":"s-s-s-shankavasukitudelft-nl"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/350816","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\/350816\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=350816"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}