


{"id":35996,"date":"2019-06-17T11:21:30","date_gmt":"2019-06-17T11:21:30","guid":{"rendered":"\/forum\/forums\/topic\/wrong-results-for-lift-force-every-simulation\/"},"modified":"2019-06-17T11:21:30","modified_gmt":"2019-06-17T11:21:30","slug":"wrong-results-for-lift-force-every-simulation","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/wrong-results-for-lift-force-every-simulation\/","title":{"rendered":"Wrong results for lift force every simulation"},"content":{"rendered":"<p><span style=\"color: #000000; font-family: verdana, geneva, lucida, 'lucida grande', arial, helvetica, sans-serif; font-size: 13.3333px; background-color: #f7f7f7;\">Hello guys.<\/span><br style=\"color: #000000; font-family: verdana, geneva, lucida, 'lucida grande', arial, helvetica, sans-serif; font-size: 13.3333px; background-color: #f7f7f7;\"><br style=\"color: #000000; font-family: verdana, geneva, lucida, 'lucida grande', arial, helvetica, sans-serif; font-size: 13.3333px; background-color: #f7f7f7;\"><span style=\"color: #000000; font-family: verdana, geneva, lucida, 'lucida grande', arial, helvetica, sans-serif; font-size: 13.3333px; background-color: #f7f7f7;\">I am simulating a steady-state water flow past a bare hull underwater vehicle in ANSYS Fluent for validating purposes based on an article. The problem is that for every velocity and angle of attack the drag coefficient is correct but the lift coefficient is off by up to 50%. I have performed mesh dependency tests, tried several turbulence models, increased\/decreased inflation layer size and y+, but still failing to understand the cause.<\/span><br style=\"color: #000000; font-family: verdana, geneva, lucida, 'lucida grande', arial, helvetica, sans-serif; font-size: 13.3333px; background-color: #f7f7f7;\"><br style=\"color: #000000; font-family: verdana, geneva, lucida, 'lucida grande', arial, helvetica, sans-serif; font-size: 13.3333px; background-color: #f7f7f7;\"><span style=\"color: #000000; font-family: verdana, geneva, lucida, 'lucida grande', arial, helvetica, sans-serif; font-size: 13.3333px; background-color: #f7f7f7;\">I&#8217;ve also turned up the gravity effect but I got no difference in the results whatsoever. Could this be because the weight is being balanced by the buoyant force? Or it is not balanced and there is no weight because the geometry is defined as hollow (I only have surfaces defining the hull body because I have used a subtract boolean feature).<\/span><br style=\"color: #000000; font-family: verdana, geneva, lucida, 'lucida grande', arial, helvetica, sans-serif; font-size: 13.3333px; background-color: #f7f7f7;\"><br style=\"color: #000000; font-family: verdana, geneva, lucida, 'lucida grande', arial, helvetica, sans-serif; font-size: 13.3333px; background-color: #f7f7f7;\"><span style=\"color: #000000; font-family: verdana, geneva, lucida, 'lucida grande', arial, helvetica, sans-serif; font-size: 13.3333px; background-color: #f7f7f7;\">Any help is appreciated. Thank you in advance!<\/span><\/p>\n","protected":false},"template":"","class_list":["post-35996","topic","type-topic","status-closed","hentry"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_bbp_old_topic_id":["8168"],"_bbp_old_topic_author_name_id":["Anonymous"],"_bbp_old_is_topic_anonymous_id":["false"],"_bbp_old_closed_status_id":["publish"],"_bbp_author_ip":[null],"_bbp_old_sticky_status_id":["normal"],"_bbp_likes_count":["0","0"],"_btv_view_count":["2054"],"_bbp_subscription":["240788"],"_bbp_topic_status":["unanswered"],"_bbp_status":["publish"],"_bbp_topic_id":["35996"],"_bbp_forum_id":["27792"],"_bbp_engagement":["199","22555","166113"],"_bbp_voice_count":["3"],"_bbp_reply_count":["20"],"_bbp_last_reply_id":["87516"],"_bbp_last_active_id":["87516"],"_bbp_last_active_time":["2019-06-20 10:16:59"]},"test":"henriquecar"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/35996","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\/35996\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=35996"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}