{"id":445541,"date":"2025-11-04T12:01:47","date_gmt":"2025-11-04T12:01:47","guid":{"rendered":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/ls-dyna-icfd-mesh_bl-card\/"},"modified":"2025-11-04T12:01:47","modified_gmt":"2025-11-04T12:01:47","slug":"ls-dyna-icfd-mesh_bl-card","status":"publish","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/ls-dyna-icfd-mesh_bl-card\/","title":{"rendered":"LS-DYNA ICFD *MESH_BL card"},"content":{"rendered":"<p>&lt;p&gt;Dear all,&lt;\/p&gt;&lt;p&gt;I use the LS-DYNA ICFD module to perform CFD simulations applied to intracranial arteries.&lt;\/p&gt;&lt;p&gt;I am currently conducting a mesh convergence study.&lt;\/p&gt;&lt;p&gt;I perform surface meshing using Tetgen embedded in VMTK.&lt;\/p&gt;&lt;p&gt;I then let LS-DYNA perform volume meshing based on the surface mesh.&lt;\/p&gt;&lt;p&gt;For the implementation of boundary layers, Tetgen uses coefficients and ratios (sublayer ratio, boundary layer thickness factor) for the meshing of prismatic elements.&lt;\/p&gt;&lt;p&gt;In LS-DYNA, the *MESH_BL card offers automatic boundary layer meshing with NELTH+1 layers when the default settings are selected.&lt;\/p&gt;&lt;p&gt;Two questions:&lt;\/p&gt;&lt;p&gt;1) I would like to know if it is possible to set a factor to calculate the boundary layer thickness rather than having to set an exact thickness in mm, cm or m via BLTH, BLFE and BLST.&lt;\/p&gt;&lt;p&gt;2) What coefficients are used by *MESH_BL in the automatic inflation of boundary layers?&lt;\/p&gt;&lt;p&gt;Thank you,&lt;\/p&gt;&lt;p&gt;Guillaume&lt;\/p&gt;<\/p>\n","protected":false},"template":"","class_list":["post-445541","topic","type-topic","status-publish","hentry","topic-tag-ansys-ls-dyna-1"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_bbp_forum_id":["27814"],"_bbp_topic_id":["445541"],"_bbp_subscription":["614160","523"],"_bbp_author_ip":["2001:861:52c6:b720:6df5:ed9e:3395:b229"],"_bbp_last_reply_id":["447268"],"_bbp_last_active_id":["447268"],"_bbp_last_active_time":["2025-11-25 21:10:09"],"_bbp_reply_count":["1"],"_bbp_reply_count_hidden":["0"],"_bbp_voice_count":["2"],"_bbp_engagement":["614160","523"],"_btv_view_count":["379"],"_bbp_topic_status":["unanswered"]},"test":"guillaume-renedobaltgroup-com"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/445541","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\/445541\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=445541"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}