{"id":165142,"date":"2023-03-17T08:59:31","date_gmt":"2023-03-17T08:59:31","guid":{"rendered":"\/knowledge\/forums\/topic\/why-the-material-velocity-in-euler-domain-is-different-from-the-incoming-material-velocity-defined-in-flow-in-boundary-condition\/"},"modified":"2023-07-31T12:30:40","modified_gmt":"2023-07-31T12:30:40","slug":"why-the-material-velocity-in-euler-domain-is-different-from-the-incoming-material-velocity-defined-in-flow-in-boundary-condition","status":"publish","type":"topic","link":"https:\/\/innovationspace.ansys.com\/knowledge\/forums\/topic\/why-the-material-velocity-in-euler-domain-is-different-from-the-incoming-material-velocity-defined-in-flow-in-boundary-condition\/","title":{"rendered":"Why the material velocity in Euler domain is different from the incoming material velocity defined in flow-in boundary condition?"},"content":{"rendered":"<p>The concept of flow-in boundary condition in Autodyn may be slightly different from the inlet boundary condition in most CFD programs.  Autodyn flow-in boundary condition is used to represent a very long jet moving in a constant velocity before impacting a specified solid or fluid. Instead of representing the entire length of the jet in Autodyn model, flow-in boundary condition is used so user doesn&#8217;t have to model the entire geometry of the long jet to reduce computing time.  Thus, user needs to have the same material in the Euler domain and fill the material with same velocity as defined in the flow-in boundary condition. Then user will observe the continuous material flow with the constant velocity in the Euler domain.  If the Euler material is initially at rest and the flow-in material has the non-zero velocity, the velocity of the Euler material predicted by Autodyn will be smaller than the incoming flow-in velocity, based upon the law of momentum conservation.<\/p>\n","protected":false},"template":"","class_list":["post-165142","topic","type-topic","status-publish","hentry","topic-tag-18-2","topic-tag-autodyn","topic-tag-boundary-conditions","topic-tag-explicit-autodyn","topic-tag-model-generation","topic-tag-structural-mechanics"],"aioseo_notices":[],"aioseo_head":"\n\t\t<!-- All in One SEO 4.9.10 - aioseo.com -->\n\t<meta name=\"description\" content=\"The concept of flow-in boundary condition in Autodyn may be slightly different from the inlet boundary condition in most CFD programs. Autodyn flow-in boundary condition is used to represent a very long jet moving in a constant velocity before impacting a specified solid or fluid. Instead of representing the entire length of the jet in\" \/>\n\t<meta name=\"robots\" content=\"max-image-preview:large\" \/>\n\t<link rel=\"canonical\" href=\"https:\/\/innovationspace.ansys.com\/knowledge\/forums\/topic\/why-the-material-velocity-in-euler-domain-is-different-from-the-incoming-material-velocity-defined-in-flow-in-boundary-condition\/\" \/>\n\t<meta name=\"generator\" content=\"All in One SEO (AIOSEO) 4.9.10\" \/>\n\t\t<meta property=\"og:locale\" content=\"en_US\" \/>\n\t\t<meta property=\"og:site_name\" content=\"Ansys Knowledge | Ansys Innovation Space\" \/>\n\t\t<meta property=\"og:type\" content=\"article\" \/>\n\t\t<meta property=\"og:title\" content=\"Why the material velocity in Euler domain is different from the incoming material velocity defined in flow-in boundary condition? | Ansys Knowledge\" \/>\n\t\t<meta property=\"og:description\" content=\"The concept of flow-in boundary condition in Autodyn may be slightly different from the inlet boundary condition in most CFD programs. Autodyn flow-in boundary condition is used to represent a very long jet moving in a constant velocity before impacting a specified solid or fluid. Instead of representing the entire length of the jet in\" \/>\n\t\t<meta property=\"og:url\" content=\"https:\/\/innovationspace.ansys.com\/knowledge\/forums\/topic\/why-the-material-velocity-in-euler-domain-is-different-from-the-incoming-material-velocity-defined-in-flow-in-boundary-condition\/\" \/>\n\t\t<meta property=\"article:published_time\" content=\"2023-03-17T08:59:31+00:00\" \/>\n\t\t<meta property=\"article:modified_time\" content=\"2023-07-31T12:30:40+00:00\" \/>\n\t\t<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n\t\t<meta name=\"twitter:title\" content=\"Why the material velocity in Euler domain is different from the incoming material velocity defined in flow-in boundary condition? | Ansys Knowledge\" \/>\n\t\t<meta name=\"twitter:description\" content=\"The concept of flow-in boundary condition in Autodyn may be slightly different from the inlet boundary condition in most CFD programs. Autodyn flow-in boundary condition is used to represent a very long jet moving in a constant velocity before impacting a specified solid or fluid. 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