{"id":35016,"date":"2019-04-29T09:04:24","date_gmt":"2019-04-29T09:04:24","guid":{"rendered":"\/forum\/forums\/topic\/refine-the-mesh-near-the-airfoil-wall\/"},"modified":"2019-04-29T09:04:24","modified_gmt":"2019-04-29T09:04:24","slug":"refine-the-mesh-near-the-airfoil-wall","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/refine-the-mesh-near-the-airfoil-wall\/","title":{"rendered":"Refine the mesh near the airfoil wall"},"content":{"rendered":"<p>Hello,<\/p>\n<p><\/p>\n<p>I have generated a structured mesh around an airfoil but I am still unable to get accurate results (I suspect due to the lack of a tight enough mesh close to the airfoil wall). I tried using an inflation around the airfoil wall but it generated bad elements and won&#8217;t even export into fluent for this reason. Is there any other way I can generate more elements around the airfoil wall, maybe subdividing the elements into even smaller elements or creating another region around the airfoil where I can refine the mesh even smaller?.<\/p>\n<p><\/p>\n<p><img decoding=\"async\" src=\"https:\/\/us.v-cdn.net\/6032193\/uploads\/attachments\/b039b67c-c457-46e8-b467-a96700a847cf\/57dd28fd-4a38-4aab-88ae-aa3e0091d3b7_a1.jpg?width=690&amp;upscale=false\" alt=\"\"><\/p>\n<p><\/p>\n<p><img decoding=\"async\" src=\"https:\/\/us.v-cdn.net\/6032193\/uploads\/attachments\/b039b67c-c457-46e8-b467-a96700a847cf\/a0f40d8f-72b4-4d08-bc92-aa3e0091efcb_a2.jpg?width=690&amp;upscale=false\" alt=\"\"><\/p>\n<p><\/p>\n<p>close view of the mesh near the airfoil.<\/p>\n<p><\/p>\n<p>Also, although the inflation layer has been deactivated, is there any way I can actually make the inflation work with the face meshing and multi-zoning such that the mesh has no degenerate or bad elements?<\/p>\n<p><\/p>\n<p><img decoding=\"async\" src=\"https:\/\/us.v-cdn.net\/6032193\/uploads\/attachments\/b039b67c-c457-46e8-b467-a96700a847cf\/1d6c6c49-4328-4420-b954-aa3e0093b0b7_a3.jpg?width=690&amp;upscale=false\" alt=\"\"><\/p>\n<p><\/p>\n<p>I have noticed that using the mesh with the inflation on (face meshing, multi-zoning off) yields the same lift and drag coefficient values as when the case is reversed (inflation off, face meshing and multi-zoning on) even though both values are not correct ( correct Cl value = 0.5 at 4 degrees AoA for NACA 23012 airfoil, I am getting Cl = 0.34&#8230;)<\/p>\n<p><\/p>\n<p>To ensure flow similarity, I ensured my Reynolds number was 1,000,000 (velocity=14.207 m\/s and chord length=1m). I used both the Spalart -Allmaras and Reynold SST turbulence models and they both give the same (inaccurate) Cl values of 0.34&#8230; .&nbsp;<span style=\"font-family: 'Open Sans', Arial, Helvetica, sans-serif; font-size: 15px;\">Top and Bottom &#8211; Stationary Wall with Specified Shear components set at 0<\/span><\/p>\n<p><\/p>\n<p style=\"box-sizing: border-box; margin: 0px 0px 10px; font-size: 15px; overflow-x: hidden; font-family: 'Open Sans', Arial, Helvetica, sans-serif;\">Outlet &#8211; 0 Gauge pressure outlet<\/p>\n<p><\/p>\n<p style=\"box-sizing: border-box; margin: 0px 0px 10px; font-size: 15px; overflow-x: hidden; font-family: 'Open Sans', Arial, Helvetica, sans-serif;\"><span style=\"font-family: Arial, Helvetica, sans-serif; font-size: 14px;\">Here is a graph showing the difference between the experimental Cl results for Reynolds number of 1,000,000 and my own values.<\/span><\/p>\n<p><\/p>\n<p><img decoding=\"async\" src=\"https:\/\/us.v-cdn.net\/6032193\/uploads\/attachments\/b039b67c-c457-46e8-b467-a96700a847cf\/702a10ea-fe53-469f-95d6-aa3e00948c2e_cl-data-1.jpg?width=690&amp;upscale=false\" alt=\"\"><\/p>\n<p><\/p>\n<p>You can see that at AoA of 0 degrees the Cl values are about the same, however, the error begins to grow as the airfoil angle of attack increases, (forgive the jaggedness of the experimental value line, I read it from a graph that is not quite clear)<\/p>\n<p><\/p>\n<p>This work is a final year project and I am running out of time, I really need the help<\/p>\n<p><\/p>\n<p>Thanks.<\/p>\n","protected":false},"template":"","class_list":["post-35016","topic","type-topic","status-closed","hentry"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_bbp_old_topic_id":["7188"],"_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":["2024"],"_bbp_topic_status":["unanswered"],"_bbp_status":["publish"],"_bbp_topic_id":["35016"],"_bbp_forum_id":["27790"],"_bbp_engagement":["62","199","159013"],"_bbp_voice_count":["3"],"_bbp_reply_count":["4"],"_bbp_last_reply_id":["84181"],"_bbp_last_active_id":["84181"],"_bbp_last_active_time":["2019-04-30 13:00:26"]},"test":"akin3rd"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/35016","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\/35016\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=35016"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}