{"id":462837,"date":"2026-08-21T14:00:33","date_gmt":"2026-08-21T14:00:33","guid":{"rendered":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/mesh_interf-error-in-icfd-solver\/"},"modified":"2026-08-21T14:00:33","modified_gmt":"2026-08-21T14:00:33","slug":"mesh_interf-error-in-icfd-solver","status":"publish","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/mesh_interf-error-in-icfd-solver\/","title":{"rendered":"MESH_INTERF error in ICFD solver"},"content":{"rendered":"

Hi everyone,<\/p>\n

I am setting up an ICFD simulation of gas flow through a porous domain<\/strong> in LS-DYNA. The model currently consists of the  fluid domain and the porous-medium region; I am not yet including structural deformation.<\/p>\n

During initialization, the simulation terminates with the following error:<\/p>\n

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*** Error 120003 (ICFD+3)<\/div>\n
ICFD::ERROR: Invalid BC on SIZE or INTERF surf. PID 1<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n
 <\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n
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The simulation does not proceed beyond initialization.<\/p>\n

I am using an ICFD volume part for the porous medium and have defined the corresponding ICFD material and porous-medium model. I suspect that the issue is related to the boundary condition assigned to the surface with PID 1<\/strong>, but I am unsure what constitutes an invalid BC for a SIZE<\/code> or INTERF<\/code> surface in this setup.<\/p>\n

Could someone please clarify:<\/p>\n

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  1. What does “Invalid BC on SIZE or INTERF surf. PID 1”<\/strong> specifically mean?<\/li>\n
  2. What boundary conditions are permitted on SIZE<\/code> and INTERF<\/code> surfaces?<\/li>\n
  3. How should the surfaces of a porous ICFD volume be defined when modelling hydrogen flow into\/through porous soil<\/strong>?<\/li>\n
  4. Is there a particular ICFD keyword or surface definition that I should check?<\/li>\n<\/ol>\n

    Thank you in advance.<\/p>\n","protected":false},"template":"","class_list":["post-462837","topic","type-topic","status-publish","hentry","topic-tag-2-way-coupled-fsi"],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t