{"id":382513,"date":"2024-09-12T16:47:43","date_gmt":"2024-09-12T16:47:43","guid":{"rendered":"https:\/\/innovationspace.ansys.com\/forum\/forums\/reply\/382513\/"},"modified":"2024-09-12T16:47:43","modified_gmt":"2024-09-12T16:47:43","slug":"382513","status":"publish","type":"reply","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/reply\/382513\/","title":{"rendered":"Reply To: ICFD Extremely high and constant drag pressure forces"},"content":{"rendered":"

<p>Hello Arnaud,<\/p><p>Which LS-DYNA version are you using?<\/p><p>Are you able to reproduce the problem with the cylinder flow example?<\/p><p>Basics : Cylinder flow — Welcome to LS-DYNA Examples<\/a><\/p><p>LSTC QA Test Case Documentation: LSTC-QA-LS-DYNA-ICFD-VAL-3.1-1 (dynaexamples.com)<\/a><\/p><p> <\/p><p>Do you see different fluid pressure contour plots with different incoming fluid velocities? The pressure drag force is calculated from the pressure as follows:<\/p><p><\/p><p>Have you tried with *ICFD_BOUNDARY_FEESLIP around the body? The ICFD training says the following:<\/p><p>”<span style=”text-decoration: underline;”>Warning<\/strong><\/span> : in some cases where friction drag is not fundamental, modeling a solid wall<br>using a free slip condition can give better numeric results than a non slip boundary<br>condition with a bad quality mesh (incorrectly capturing the boundary layer can lead<br>to over constrains in the pressure field of the flow).”<\/p><p> <\/p><p>Give it a try and let me know how it goes.<\/p><p>Note that Ansys employees are not allowed to upload and download files on the Ansys Forum. If you are a commercial customer, please create a support case on ACSS and we will have a look at your specific model:<\/p><p>customer.ansys.com<\/p><p> <\/p><p>Reno.<\/p><\/p>\n","protected":false},"template":"","class_list":["post-382513","reply","type-reply","status-publish","hentry"],"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\n\t\t\n\t\t\n\t\t