{"id":164989,"date":"2023-03-17T08:59:08","date_gmt":"2023-03-17T08:59:08","guid":{"rendered":"\/knowledge\/forums\/topic\/when-i-read-a-msh-file-into-fluent-and-try-to-implement-a-momentum-source-based-on-an-expression-it-fails-to-get-applied-and-my-source-term-gets-disabled-example-enable-an-aeoex-momentumae\/"},"modified":"2023-07-31T12:26:40","modified_gmt":"2023-07-31T12:26:40","slug":"when-i-read-a-msh-file-into-fluent-and-try-to-implement-a-momentum-source-based-on-an-expression-it-fails-to-get-applied-and-my-source-term-gets-disabled-example-enable-an-aeoex-momentumae","status":"publish","type":"topic","link":"https:\/\/innovationspace.ansys.com\/knowledge\/forums\/topic\/when-i-read-a-msh-file-into-fluent-and-try-to-implement-a-momentum-source-based-on-an-expression-it-fails-to-get-applied-and-my-source-term-gets-disabled-example-enable-an-aeoex-momentumae\/","title":{"rendered":"When I read a msh file into Fluent and try to implement a Momentum source based on an Expression, it fails to get applied and my source term gets disabled.  Example:     Enable an \u00e2\u20ac\u0153X Momentum\u00e2\u20ac\u009d source in a zone and set the field to the expression type.     Enter the expression: AreaAve(StaticPressure,[&#8216;wall-mid&#8217;])\/1[m]. (Or create the expression first and then assign it)     Click \u00e2\u20ac\u0153OK\u00e2\u20ac\u009d on the \u00e2\u20ac\u0153X Momentum sources\u00e2\u20ac\u009d panel.     The interface will briefly show the proper thing (one momentum source for X), then will disable the momentum sources checkbox.  Why does this happen?  Is there a workaround"},"content":{"rendered":"<p>This is a known defect and it affected releases 2021R2, 2022R1 and 2022R2.  This happens only with expressions which cannot be evaluated.  The workaround is to back all the way out of the zone setup and redo all the steps to set up the source.  It should work with the second try.  If you are working with a .cas file, save the save the cas  (source term will not be set up, but expression can be present under Named Expressions), close down Fluent, relaunch and repeat the steps to creating the source<\/p>\n","protected":false},"template":"","class_list":["post-164989","topic","type-topic","status-publish","hentry","topic-tag-2022-r2","topic-tag-fluent","topic-tag-fluid-dynamics","topic-tag-general-fluent","topic-tag-udf-scripting-act-pyansys"],"aioseo_notices":[],"aioseo_head":"\n\t\t<!-- All in One SEO 4.9.10 - aioseo.com -->\n\t<meta name=\"description\" content=\"This is a known defect and it affected releases 2021R2, 2022R1 and 2022R2. This happens only with expressions which cannot be evaluated. The workaround is to back all the way out of the zone setup and redo all the steps to set up the source. It should work with the second try. If you are\" \/>\n\t<meta name=\"robots\" content=\"max-image-preview:large\" \/>\n\t<link rel=\"canonical\" href=\"https:\/\/innovationspace.ansys.com\/knowledge\/forums\/topic\/when-i-read-a-msh-file-into-fluent-and-try-to-implement-a-momentum-source-based-on-an-expression-it-fails-to-get-applied-and-my-source-term-gets-disabled-example-enable-an-aeoex-momentumae\/\" \/>\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=\"When I read a msh file into Fluent and try to implement a Momentum source based on an Expression, it fails to get applied and my source term gets disabled. Example: Enable an \u00e2\u20ac\u0153X Momentum\u00e2\u20ac\u009d source in a zone and set the field to the expression type. Enter the expression: AreaAve(StaticPressure,[\u2018wall-mid\u2019])\/1[m]. (Or create the expression first and then assign it) Click \u00e2\u20ac\u0153OK\u00e2\u20ac\u009d on the \u00e2\u20ac\u0153X Momentum sources\u00e2\u20ac\u009d panel. The interface will briefly show the proper thing (one momentum source for X), then will disable the momentum sources checkbox. Why does this happen? Is there a workaround | Ansys Knowledge\" \/>\n\t\t<meta property=\"og:description\" content=\"This is a known defect and it affected releases 2021R2, 2022R1 and 2022R2. This happens only with expressions which cannot be evaluated. The workaround is to back all the way out of the zone setup and redo all the steps to set up the source. It should work with the second try. If you are\" \/>\n\t\t<meta property=\"og:url\" content=\"https:\/\/innovationspace.ansys.com\/knowledge\/forums\/topic\/when-i-read-a-msh-file-into-fluent-and-try-to-implement-a-momentum-source-based-on-an-expression-it-fails-to-get-applied-and-my-source-term-gets-disabled-example-enable-an-aeoex-momentumae\/\" \/>\n\t\t<meta property=\"article:published_time\" content=\"2023-03-17T08:59:08+00:00\" \/>\n\t\t<meta property=\"article:modified_time\" content=\"2023-07-31T12:26:40+00:00\" \/>\n\t\t<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n\t\t<meta name=\"twitter:title\" content=\"When I read a msh file into Fluent and try to implement a Momentum source based on an Expression, it fails to get applied and my source term gets disabled. Example: Enable an \u00e2\u20ac\u0153X Momentum\u00e2\u20ac\u009d source in a zone and set the field to the expression type. Enter the expression: AreaAve(StaticPressure,[\u2018wall-mid\u2019])\/1[m]. (Or create the expression first and then assign it) Click \u00e2\u20ac\u0153OK\u00e2\u20ac\u009d on the \u00e2\u20ac\u0153X Momentum sources\u00e2\u20ac\u009d panel. The interface will briefly show the proper thing (one momentum source for X), then will disable the momentum sources checkbox. Why does this happen? Is there a workaround | Ansys Knowledge\" \/>\n\t\t<meta name=\"twitter:description\" content=\"This is a known defect and it affected releases 2021R2, 2022R1 and 2022R2. This happens only with expressions which cannot be evaluated. The workaround is to back all the way out of the zone setup and redo all the steps to set up the source. It should work with the second try. 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If you are","canonical_url":"https:\/\/innovationspace.ansys.com\/knowledge\/forums\/topic\/when-i-read-a-msh-file-into-fluent-and-try-to-implement-a-momentum-source-based-on-an-expression-it-fails-to-get-applied-and-my-source-term-gets-disabled-example-enable-an-aeoex-momentumae\/","robots":"max-image-preview:large","keywords":"","webmasterTools":{"miscellaneous":""},"schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":"BreadcrumbList","@id":"https:\/\/innovationspace.ansys.com\/knowledge\/forums\/topic\/when-i-read-a-msh-file-into-fluent-and-try-to-implement-a-momentum-source-based-on-an-expression-it-fails-to-get-applied-and-my-source-term-gets-disabled-example-enable-an-aeoex-momentumae\/#breadcrumblist","itemListElement":[{"@type":"ListItem","@id":"https:\/\/innovationspace.ansys.com\/knowledge#listItem","position":1,"name":"Home","item":"https:\/\/innovationspace.ansys.com\/knowledge","nextItem":{"@type":"ListItem","@id":"https:\/\/innovationspace.ansys.com\/knowledge\/topics\/#listItem","name":"Topics"}},{"@type":"ListItem","@id":"https:\/\/innovationspace.ansys.com\/knowledge\/topics\/#listItem","position":2,"name":"Topics","item":"https:\/\/innovationspace.ansys.com\/knowledge\/topics\/","nextItem":{"@type":"ListItem","@id":"https:\/\/innovationspace.ansys.com\/knowledge\/forums\/topic-tag\/fluent\/#listItem","name":"fluent"},"previousItem":{"@type":"ListItem","@id":"https:\/\/innovationspace.ansys.com\/knowledge#listItem","name":"Home"}},{"@type":"ListItem","@id":"https:\/\/innovationspace.ansys.com\/knowledge\/forums\/topic-tag\/fluent\/#listItem","position":3,"name":"fluent","item":"https:\/\/innovationspace.ansys.com\/knowledge\/forums\/topic-tag\/fluent\/","nextItem":{"@type":"ListItem","@id":"https:\/\/innovationspace.ansys.com\/knowledge\/forums\/topic\/when-i-read-a-msh-file-into-fluent-and-try-to-implement-a-momentum-source-based-on-an-expression-it-fails-to-get-applied-and-my-source-term-gets-disabled-example-enable-an-aeoex-momentumae\/#listItem","name":"When I read a msh file into Fluent and try to implement a Momentum source based on an Expression, it fails to get applied and my source term gets disabled.  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Is there a workaround"},"previousItem":{"@type":"ListItem","@id":"https:\/\/innovationspace.ansys.com\/knowledge\/topics\/#listItem","name":"Topics"}},{"@type":"ListItem","@id":"https:\/\/innovationspace.ansys.com\/knowledge\/forums\/topic\/when-i-read-a-msh-file-into-fluent-and-try-to-implement-a-momentum-source-based-on-an-expression-it-fails-to-get-applied-and-my-source-term-gets-disabled-example-enable-an-aeoex-momentumae\/#listItem","position":4,"name":"When I read a msh file into Fluent and try to implement a Momentum source based on an Expression, it fails to get applied and my source term gets disabled.  Example:     Enable an \u00e2\u20ac\u0153X Momentum\u00e2\u20ac\u009d source in a zone and set the field to the expression type.     Enter the expression: AreaAve(StaticPressure,[&#8216;wall-mid&#8217;])\/1[m]. 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Is there a workaround","previousItem":{"@type":"ListItem","@id":"https:\/\/innovationspace.ansys.com\/knowledge\/forums\/topic-tag\/fluent\/#listItem","name":"fluent"}}]},{"@type":"Organization","@id":"https:\/\/innovationspace.ansys.com\/knowledge\/#organization","name":"Ansys Knowledge","description":"Ansys Innovation Space","url":"https:\/\/innovationspace.ansys.com\/knowledge\/"},{"@type":"WebPage","@id":"https:\/\/innovationspace.ansys.com\/knowledge\/forums\/topic\/when-i-read-a-msh-file-into-fluent-and-try-to-implement-a-momentum-source-based-on-an-expression-it-fails-to-get-applied-and-my-source-term-gets-disabled-example-enable-an-aeoex-momentumae\/#webpage","url":"https:\/\/innovationspace.ansys.com\/knowledge\/forums\/topic\/when-i-read-a-msh-file-into-fluent-and-try-to-implement-a-momentum-source-based-on-an-expression-it-fails-to-get-applied-and-my-source-term-gets-disabled-example-enable-an-aeoex-momentumae\/","name":"When I read a msh file into Fluent and try to implement a Momentum source based on an Expression, it fails to get applied and my source term gets disabled. 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If you are","inLanguage":"en-US","isPartOf":{"@id":"https:\/\/innovationspace.ansys.com\/knowledge\/#website"},"breadcrumb":{"@id":"https:\/\/innovationspace.ansys.com\/knowledge\/forums\/topic\/when-i-read-a-msh-file-into-fluent-and-try-to-implement-a-momentum-source-based-on-an-expression-it-fails-to-get-applied-and-my-source-term-gets-disabled-example-enable-an-aeoex-momentumae\/#breadcrumblist"},"datePublished":"2023-03-17T08:59:08+00:00","dateModified":"2023-07-31T12:26:40+00:00"},{"@type":"WebSite","@id":"https:\/\/innovationspace.ansys.com\/knowledge\/#website","url":"https:\/\/innovationspace.ansys.com\/knowledge\/","name":"Ansys Knowledge","description":"Ansys Innovation Space","inLanguage":"en-US","publisher":{"@id":"https:\/\/innovationspace.ansys.com\/knowledge\/#organization"}}]},"og:locale":"en_US","og:site_name":"Ansys Knowledge | Ansys Innovation Space","og:type":"article","og:title":"When I read a msh file into Fluent and try to implement a Momentum source based on an Expression, it fails to get applied and my source term gets disabled. Example: Enable an \u00e2\u20ac\u0153X Momentum\u00e2\u20ac\u009d source in a zone and set the field to the expression type. Enter the expression: AreaAve(StaticPressure,[\u2018wall-mid\u2019])\/1[m]. (Or create the expression first and then assign it) Click \u00e2\u20ac\u0153OK\u00e2\u20ac\u009d on the \u00e2\u20ac\u0153X Momentum sources\u00e2\u20ac\u009d panel. The interface will briefly show the proper thing (one momentum source for X), then will disable the momentum sources checkbox. Why does this happen? Is there a workaround | Ansys Knowledge","og:description":"This is a known defect and it affected releases 2021R2, 2022R1 and 2022R2. This happens only with expressions which cannot be evaluated. The workaround is to back all the way out of the zone setup and redo all the steps to set up the source. It should work with the second try. If you are","og:url":"https:\/\/innovationspace.ansys.com\/knowledge\/forums\/topic\/when-i-read-a-msh-file-into-fluent-and-try-to-implement-a-momentum-source-based-on-an-expression-it-fails-to-get-applied-and-my-source-term-gets-disabled-example-enable-an-aeoex-momentumae\/","article:published_time":"2023-03-17T08:59:08+00:00","article:modified_time":"2023-07-31T12:26:40+00:00","twitter:card":"summary_large_image","twitter:title":"When I read a msh file into Fluent and try to implement a Momentum source based on an Expression, it fails to get applied and my source term gets disabled. Example: Enable an \u00e2\u20ac\u0153X Momentum\u00e2\u20ac\u009d source in a zone and set the field to the expression type. Enter the expression: AreaAve(StaticPressure,[\u2018wall-mid\u2019])\/1[m]. (Or create the expression first and then assign it) Click \u00e2\u20ac\u0153OK\u00e2\u20ac\u009d on the \u00e2\u20ac\u0153X Momentum sources\u00e2\u20ac\u009d panel. The interface will briefly show the proper thing (one momentum source for X), then will disable the momentum sources checkbox. Why does this happen? Is there a workaround | Ansys Knowledge","twitter:description":"This is a known defect and it affected releases 2021R2, 2022R1 and 2022R2. This happens only with expressions which cannot be evaluated. The workaround is to back all the way out of the zone setup and redo all the steps to set up the source. It should work with the second try. If you are"},"aioseo_meta_data":{"post_id":"164989","title":null,"description":null,"keywords":null,"keyphrases":null,"primary_term":null,"canonical_url":null,"og_title":null,"og_description":null,"og_object_type":"default","og_image_type":"default","og_image_url":null,"og_image_width":null,"og_image_height":null,"og_image_custom_url":null,"og_image_custom_fields":null,"og_video":null,"og_custom_url":null,"og_article_section":null,"og_article_tags":null,"twitter_use_og":false,"twitter_card":"default","twitter_image_type":"default","twitter_image_url":null,"twitter_image_custom_url":null,"twitter_image_custom_fields":null,"twitter_title":null,"twitter_description":null,"schema":{"blockGraphs":[],"customGraphs":[],"default":{"data":{"Article":[],"Course":[],"Dataset":[],"FAQPage":[],"Movie":[],"Person":[],"Product":[],"ProductReview":[],"Car":[],"Recipe":[],"Service":[],"SoftwareApplication":[],"WebPage":[]},"graphName":"","isEnabled":true},"graphs":[]},"schema_type":"default","schema_type_options":null,"pillar_content":false,"robots_default":true,"robots_noindex":false,"robots_noarchive":false,"robots_nosnippet":false,"robots_nofollow":false,"robots_noimageindex":false,"robots_noodp":false,"robots_notranslate":false,"robots_max_snippet":null,"robots_max_videopreview":null,"robots_max_imagepreview":"large","priority":null,"frequency":null,"local_seo":null,"limit_modified_date":false,"created":"2025-10-17 21:48:06","updated":"2026-07-29 15:31:58","ai":null,"breadcrumb_settings":null,"seo_analyzer_scan_date":null},"aioseo_breadcrumb":"<div class=\"aioseo-breadcrumbs\"><span class=\"aioseo-breadcrumb\">\n\t\t\t<a href=\"https:\/\/innovationspace.ansys.com\/knowledge\" title=\"Home\">Home<\/a>\n\t\t<\/span><span class=\"aioseo-breadcrumb-separator\">&raquo;<\/span><span class=\"aioseo-breadcrumb\">\n\t\t\t<a href=\"https:\/\/innovationspace.ansys.com\/knowledge\/topics\/\" title=\"Topics\">Topics<\/a>\n\t\t<\/span><span class=\"aioseo-breadcrumb-separator\">&raquo;<\/span><span class=\"aioseo-breadcrumb\">\n\t\t\t<a href=\"https:\/\/innovationspace.ansys.com\/knowledge\/forums\/topic-tag\/fluent\/\" title=\"fluent\">fluent<\/a>\n\t\t<\/span><span class=\"aioseo-breadcrumb-separator\">&raquo;<\/span><span class=\"aioseo-breadcrumb\">\n\t\t\tWhen I read a msh file into Fluent and try to implement a Momentum source based on an Expression, it fails to get applied and my source term gets disabled.  Example:     Enable an \u00e2\u20ac\u0153X Momentum\u00e2\u20ac\u009d source in a zone and set the field to the expression type.     Enter the expression: AreaAve(StaticPressure,[\u2018wall-mid\u2019])\/1[m]. (Or create the expression first and then assign it)     Click \u00e2\u20ac\u0153OK\u00e2\u20ac\u009d on the \u00e2\u20ac\u0153X Momentum sources\u00e2\u20ac\u009d panel.     The interface will briefly show the proper thing (one momentum source for X), then will disable the momentum sources checkbox.  Why does this happen?  Is there a workaround\n\t\t<\/span><\/div>","aioseo_breadcrumb_json":[{"label":"Home","link":"https:\/\/innovationspace.ansys.com\/knowledge"},{"label":"Topics","link":"https:\/\/innovationspace.ansys.com\/knowledge\/topics\/"},{"label":"fluent","link":"https:\/\/innovationspace.ansys.com\/knowledge\/forums\/topic-tag\/fluent\/"},{"label":"When I read a msh file into Fluent and try to implement a Momentum source based on an Expression, it fails to get applied and my source term gets disabled.  Example:     Enable an \u00e2\u20ac\u0153X Momentum\u00e2\u20ac\u009d source in a zone and set the field to the expression type.     Enter the expression: AreaAve(StaticPressure,[&#8216;wall-mid&#8217;])\/1[m]. (Or create the expression first and then assign it)     Click \u00e2\u20ac\u0153OK\u00e2\u20ac\u009d on the \u00e2\u20ac\u0153X Momentum sources\u00e2\u20ac\u009d panel.     The interface will briefly show the proper thing (one momentum source for X), then will disable the momentum sources checkbox.  Why does this happen?  Is there a workaround","link":"https:\/\/innovationspace.ansys.com\/knowledge\/forums\/topic\/when-i-read-a-msh-file-into-fluent-and-try-to-implement-a-momentum-source-based-on-an-expression-it-fails-to-get-applied-and-my-source-term-gets-disabled-example-enable-an-aeoex-momentumae\/"}],"acf":[],"custom_fields":[{"0":{"_wp_page_template":["default"],"_bbp_last_active_time":["3-15-2023  20:20:10"],"_bbp_forum_id":["27796"],"_bbp_author_ip":["23.56.168.180"],"_btv_view_count":["726"],"siebel_km_number":["2067282"],"product_version":["2022 R2"],"km_published_date":["2022-02-10T00:00:00.000Z"],"family":["Fluid Dynamics"],"application_name":["FLUENT"]},"test":"articlesansys-com"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/knowledge\/wp-json\/wp\/v2\/topics\/164989","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/innovationspace.ansys.com\/knowledge\/wp-json\/wp\/v2\/topics"}],"about":[{"href":"https:\/\/innovationspace.ansys.com\/knowledge\/wp-json\/wp\/v2\/types\/topic"}],"version-history":[{"count":0,"href":"https:\/\/innovationspace.ansys.com\/knowledge\/wp-json\/wp\/v2\/topics\/164989\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/knowledge\/wp-json\/wp\/v2\/media?parent=164989"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}