![](\"http:\/\/wec-sim.github.io\/WEC-Sim\/master\/_images\/RM3_Geom.png\")
<\/p>\nDeal all<\/p>\n
For a coaxial double-buoy device, e.g., RM3, the two bodies are only allowed to move relative to each other in the heave direction. In the linear frequency-domain calculations, the wave-excitation loads are obtained by fixing the two objects without any motion. On the other hand, the wave-radiation loads are obtained by forcing one of the objects to move with unit ampitude in one direction.<\/p>\n
<\/p>\n
For example, added mass coefficient matrix of the two objects has a size of 12*12. Added mass A(3,3) is obtained by forcing object 1 to move with unit ampitude in the heave direction, and A(3,9) is the added mass imposed on object 2 by the forced motion of object 1 in the heave direction. However, due to the rigid constraint between the two bodies, I don’t think the added mass and radiation damping can be implemented in the surge direction.<\/p>\n
Specifically, the added mass A(1,1) is obtained by forcing object 1 to move with unit ampitude in the surge direction, and A(1,7) is the added mass imposed on object 2 by the forced motion of object 1 in the surge direction. Likewise, A(7,7) is obtained by forcing object 2 to move in the surge direction, and A(7,1) is the added mass imposed on object 1 by the forced motion of object 2 in the surge direction.<\/p>\n
Considering the existence of rigid constraints between the two bodies, should the radiation coefficients be calculated in the surge, sway, roll, pitch and yaw directions? For the outer bodies with a moonpool, the forced motions of one of the two objects in the five directions would cause large-amplitude radiation waves, especially if the gap between the two objects is small.<\/p>\n
For the RM3 device with a structural height of 38 m, radiation waves generated by the forced motion of inner body in the pitch direction are monitored to be as high as a few hundred meters, and the radiation waves generated by that in the surge direction are tens of meters. This is obviously not normal. I think it has something to do with the forced motion of a single object. Can AQWA implement constraints between two objects in frequency-domain calculations, and could you please give me some suggestions on this issue? <\/p>\n
Best regards, Tianyuan<\/p>\n","protected":false},"template":"","class_list":["post-312710","topic","type-topic","status-closed","hentry"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_bbp_subscription":["278012","183765"],"_bbp_author_ip":["23.206.193.59"]," _bbp_last_reply_id":["0"]," _bbp_likes_count":["0"],"_btv_view_count":["537"],"_bbp_topic_status":["unanswered"],"_bbp_status":["publish"],"_bbp_notification_enabled":["183765","183765","183765"],"_bbp_topic_id":["312710"],"_bbp_forum_id":["27796"],"_bbp_engagement":["183765","278012"],"_bbp_voice_count":["2"],"_bbp_reply_count":["8"],"_bbp_last_reply_id":["318211"],"_bbp_last_active_id":["318211"],"_bbp_last_active_time":["2023-11-17 15:05:01"]},"test":"wangtianyuanstu-ouc-edu-cn"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/312710","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\/312710\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=312710"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}