{"id":53625,"date":"2021-03-19T21:21:56","date_gmt":"2021-03-19T21:21:56","guid":{"rendered":"\/forum\/forums\/topic\/turbulent-viscosity-udf\/"},"modified":"2021-03-19T21:21:56","modified_gmt":"2021-03-19T21:21:56","slug":"turbulent-viscosity-udf","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/turbulent-viscosity-udf\/","title":{"rendered":"Turbulent Viscosity UDF?"},"content":{"rendered":"<p>Hello,nnI am trying to write a UDF to calculate turbulent viscosity based on Prandtl&#8217;s mixing layer model (mu_t = a*delta) to use with the Spalart-Allmaras model. I performed the simulation using the default values first so I have a solution blueprint and then compiled the UDF, changed the Turbulent Viscosity in the Viscous dialog box to the udf value. However, I am now getting floating point exception in the first iteration itself. Could someone check my code, please? Not sure why I&#8217;m getting that error.nnI&#8217;m running a 2D second-order, pressure-based solver with Coupled scheme.n#include udf.hDEFINE_TURBULENT_VISCOSITY(mu_t1,c,t)n{ntreal a_const = 0.1;ntreal rho = C_R(c,t);ntreal dudy = C_DUDY(c,t);ntreal del = .000125;ntreal lm = a_const*del;ntreal mu_t = dudy*SQR(lm);ntntreturn mu_t;nn<\/p>\n","protected":false},"template":"","class_list":["post-53625","topic","type-topic","status-closed","hentry"],"aioseo_notices":[],"aioseo_head":"\n\t\t<!-- All in One SEO 4.9.10 - aioseo.com -->\n\t<meta name=\"description\" content=\"Hello,nnI am trying to write a UDF to calculate turbulent viscosity based on Prandtl&#039;s mixing layer model (mu_t = a*delta) to use with the Spalart-Allmaras model. I performed the simulation using the default values first so I have a solution blueprint and then compiled the UDF, changed the Turbulent Viscosity in the Viscous dialog box\" \/>\n\t<meta name=\"robots\" content=\"max-image-preview:large\" \/>\n\t<link rel=\"canonical\" href=\"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/turbulent-viscosity-udf\/\" \/>\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 Learning Forum | Ansys Innovation Space\" \/>\n\t\t<meta property=\"og:type\" content=\"article\" \/>\n\t\t<meta property=\"og:title\" content=\"Turbulent Viscosity UDF? | Ansys Learning Forum\" \/>\n\t\t<meta property=\"og:description\" content=\"Hello,nnI am trying to write a UDF to calculate turbulent viscosity based on Prandtl&#039;s mixing layer model (mu_t = a*delta) to use with the Spalart-Allmaras model. I performed the simulation using the default values first so I have a solution blueprint and then compiled the UDF, changed the Turbulent Viscosity in the Viscous dialog box\" \/>\n\t\t<meta property=\"og:url\" content=\"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/turbulent-viscosity-udf\/\" \/>\n\t\t<meta property=\"article:published_time\" content=\"2021-03-19T21:21:56+00:00\" \/>\n\t\t<meta property=\"article:modified_time\" content=\"2021-03-19T21:21:56+00:00\" \/>\n\t\t<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n\t\t<meta name=\"twitter:title\" content=\"Turbulent Viscosity UDF? | Ansys Learning Forum\" \/>\n\t\t<meta name=\"twitter:description\" content=\"Hello,nnI am trying to write a UDF to calculate turbulent viscosity based on Prandtl&#039;s mixing layer model (mu_t = a*delta) to use with the Spalart-Allmaras model. I performed the simulation using the default values first so I have a solution blueprint and then compiled the UDF, changed the Turbulent Viscosity in the Viscous dialog box\" \/>\n\t\t<script type=\"application\/ld+json\" class=\"aioseo-schema\">\n\t\t\t{\"@context\":\"https:\\\/\\\/schema.org\",\"@graph\":[{\"@type\":\"BreadcrumbList\",\"@id\":\"https:\\\/\\\/innovationspace.ansys.com\\\/forum\\\/forums\\\/topic\\\/turbulent-viscosity-udf\\\/#breadcrumblist\",\"itemListElement\":[{\"@type\":\"ListItem\",\"@id\":\"https:\\\/\\\/innovationspace.ansys.com\\\/forum#listItem\",\"position\":1,\"name\":\"Home\",\"item\":\"https:\\\/\\\/innovationspace.ansys.com\\\/forum\",\"nextItem\":{\"@type\":\"ListItem\",\"@id\":\"https:\\\/\\\/innovationspace.ansys.com\\\/forum\\\/topics\\\/#listItem\",\"name\":\"Topics\"}},{\"@type\":\"ListItem\",\"@id\":\"https:\\\/\\\/innovationspace.ansys.com\\\/forum\\\/topics\\\/#listItem\",\"position\":2,\"name\":\"Topics\",\"item\":\"https:\\\/\\\/innovationspace.ansys.com\\\/forum\\\/topics\\\/\",\"nextItem\":{\"@type\":\"ListItem\",\"@id\":\"https:\\\/\\\/innovationspace.ansys.com\\\/forum\\\/forums\\\/topic\\\/turbulent-viscosity-udf\\\/#listItem\",\"name\":\"Turbulent Viscosity UDF?\"},\"previousItem\":{\"@type\":\"ListItem\",\"@id\":\"https:\\\/\\\/innovationspace.ansys.com\\\/forum#listItem\",\"name\":\"Home\"}},{\"@type\":\"ListItem\",\"@id\":\"https:\\\/\\\/innovationspace.ansys.com\\\/forum\\\/forums\\\/topic\\\/turbulent-viscosity-udf\\\/#listItem\",\"position\":3,\"name\":\"Turbulent Viscosity UDF?\",\"previousItem\":{\"@type\":\"ListItem\",\"@id\":\"https:\\\/\\\/innovationspace.ansys.com\\\/forum\\\/topics\\\/#listItem\",\"name\":\"Topics\"}}]},{\"@type\":\"Organization\",\"@id\":\"https:\\\/\\\/innovationspace.ansys.com\\\/forum\\\/#organization\",\"name\":\"Ansys Learning Forum\",\"description\":\"Ansys Innovation Space\",\"url\":\"https:\\\/\\\/innovationspace.ansys.com\\\/forum\\\/\"},{\"@type\":\"WebPage\",\"@id\":\"https:\\\/\\\/innovationspace.ansys.com\\\/forum\\\/forums\\\/topic\\\/turbulent-viscosity-udf\\\/#webpage\",\"url\":\"https:\\\/\\\/innovationspace.ansys.com\\\/forum\\\/forums\\\/topic\\\/turbulent-viscosity-udf\\\/\",\"name\":\"Turbulent Viscosity UDF? | Ansys Learning Forum\",\"description\":\"Hello,nnI am trying to write a UDF to calculate turbulent viscosity based on Prandtl's mixing layer model (mu_t = a*delta) to use with the Spalart-Allmaras model. I performed the simulation using the default values first so I have a solution blueprint and then compiled the UDF, changed the Turbulent Viscosity in the Viscous dialog box\",\"inLanguage\":\"en-US\",\"isPartOf\":{\"@id\":\"https:\\\/\\\/innovationspace.ansys.com\\\/forum\\\/#website\"},\"breadcrumb\":{\"@id\":\"https:\\\/\\\/innovationspace.ansys.com\\\/forum\\\/forums\\\/topic\\\/turbulent-viscosity-udf\\\/#breadcrumblist\"},\"datePublished\":\"2021-03-19T21:21:56+00:00\",\"dateModified\":\"2021-03-19T21:21:56+00:00\"},{\"@type\":\"WebSite\",\"@id\":\"https:\\\/\\\/innovationspace.ansys.com\\\/forum\\\/#website\",\"url\":\"https:\\\/\\\/innovationspace.ansys.com\\\/forum\\\/\",\"name\":\"Ansys Learning Forum\",\"description\":\"Ansys Innovation Space\",\"inLanguage\":\"en-US\",\"publisher\":{\"@id\":\"https:\\\/\\\/innovationspace.ansys.com\\\/forum\\\/#organization\"}}]}\n\t\t<\/script>\n\t\t<!-- All in One SEO -->\n\n","aioseo_head_json":{"title":"Turbulent Viscosity UDF? | Ansys Learning Forum","description":"Hello,nnI am trying to write a UDF to calculate turbulent viscosity based on Prandtl's mixing layer model (mu_t = a*delta) to use with the Spalart-Allmaras model. I performed the simulation using the default values first so I have a solution blueprint and then compiled the UDF, changed the Turbulent Viscosity in the Viscous dialog box","canonical_url":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/turbulent-viscosity-udf\/","robots":"max-image-preview:large","keywords":"","webmasterTools":{"miscellaneous":""},"schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":"BreadcrumbList","@id":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/turbulent-viscosity-udf\/#breadcrumblist","itemListElement":[{"@type":"ListItem","@id":"https:\/\/innovationspace.ansys.com\/forum#listItem","position":1,"name":"Home","item":"https:\/\/innovationspace.ansys.com\/forum","nextItem":{"@type":"ListItem","@id":"https:\/\/innovationspace.ansys.com\/forum\/topics\/#listItem","name":"Topics"}},{"@type":"ListItem","@id":"https:\/\/innovationspace.ansys.com\/forum\/topics\/#listItem","position":2,"name":"Topics","item":"https:\/\/innovationspace.ansys.com\/forum\/topics\/","nextItem":{"@type":"ListItem","@id":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/turbulent-viscosity-udf\/#listItem","name":"Turbulent Viscosity UDF?"},"previousItem":{"@type":"ListItem","@id":"https:\/\/innovationspace.ansys.com\/forum#listItem","name":"Home"}},{"@type":"ListItem","@id":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/turbulent-viscosity-udf\/#listItem","position":3,"name":"Turbulent Viscosity UDF?","previousItem":{"@type":"ListItem","@id":"https:\/\/innovationspace.ansys.com\/forum\/topics\/#listItem","name":"Topics"}}]},{"@type":"Organization","@id":"https:\/\/innovationspace.ansys.com\/forum\/#organization","name":"Ansys Learning Forum","description":"Ansys Innovation Space","url":"https:\/\/innovationspace.ansys.com\/forum\/"},{"@type":"WebPage","@id":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/turbulent-viscosity-udf\/#webpage","url":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/turbulent-viscosity-udf\/","name":"Turbulent Viscosity UDF? | Ansys Learning Forum","description":"Hello,nnI am trying to write a UDF to calculate turbulent viscosity based on Prandtl's mixing layer model (mu_t = a*delta) to use with the Spalart-Allmaras model. I performed the simulation using the default values first so I have a solution blueprint and then compiled the UDF, changed the Turbulent Viscosity in the Viscous dialog box","inLanguage":"en-US","isPartOf":{"@id":"https:\/\/innovationspace.ansys.com\/forum\/#website"},"breadcrumb":{"@id":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/turbulent-viscosity-udf\/#breadcrumblist"},"datePublished":"2021-03-19T21:21:56+00:00","dateModified":"2021-03-19T21:21:56+00:00"},{"@type":"WebSite","@id":"https:\/\/innovationspace.ansys.com\/forum\/#website","url":"https:\/\/innovationspace.ansys.com\/forum\/","name":"Ansys Learning Forum","description":"Ansys Innovation Space","inLanguage":"en-US","publisher":{"@id":"https:\/\/innovationspace.ansys.com\/forum\/#organization"}}]},"og:locale":"en_US","og:site_name":"Ansys Learning Forum | Ansys Innovation Space","og:type":"article","og:title":"Turbulent Viscosity UDF? | Ansys Learning Forum","og:description":"Hello,nnI am trying to write a UDF to calculate turbulent viscosity based on Prandtl's mixing layer model (mu_t = a*delta) to use with the Spalart-Allmaras model. I performed the simulation using the default values first so I have a solution blueprint and then compiled the UDF, changed the Turbulent Viscosity in the Viscous dialog box","og:url":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/turbulent-viscosity-udf\/","article:published_time":"2021-03-19T21:21:56+00:00","article:modified_time":"2021-03-19T21:21:56+00:00","twitter:card":"summary_large_image","twitter:title":"Turbulent Viscosity UDF? | Ansys Learning Forum","twitter:description":"Hello,nnI am trying to write a UDF to calculate turbulent viscosity based on Prandtl's mixing layer model (mu_t = a*delta) to use with the Spalart-Allmaras model. I performed the simulation using the default values first so I have a solution blueprint and then compiled the UDF, changed the Turbulent Viscosity in the Viscous dialog box"},"aioseo_meta_data":{"post_id":"53625","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":"content","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":true,"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":"2024-10-28 22:52:49","updated":"2024-10-28 22:52:49","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\/forum\" 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\/forum\/topics\/\" title=\"Topics\">Topics<\/a>\n\t\t<\/span><span class=\"aioseo-breadcrumb-separator\">&raquo;<\/span><span class=\"aioseo-breadcrumb\">\n\t\t\tTurbulent Viscosity UDF?\n\t\t<\/span><\/div>","aioseo_breadcrumb_json":[{"label":"Home","link":"https:\/\/innovationspace.ansys.com\/forum"},{"label":"Topics","link":"https:\/\/innovationspace.ansys.com\/forum\/topics\/"},{"label":"Turbulent Viscosity UDF?","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/turbulent-viscosity-udf\/"}],"acf":[],"custom_fields":[{"0":{"_bbp_old_topic_id":["25946"],"_bbp_old_topic_author_name_id":["Anonymous"],"_bbp_old_is_topic_anonymous_id":["false"],"_bbp_old_closed_status_id":["publish"],"_bbp_author_ip":["?\u001fF?"],"_bbp_old_sticky_status_id":["normal"],"_bbp_likes_count":["0"],"_btv_view_count":["499"],"_bbp_topic_status":["unanswered"],"_bbp_status":["publish"],"_bbp_topic_id":["53625"],"_bbp_forum_id":["27792"],"_bbp_engagement":["25","184487","186624"],"_bbp_voice_count":["3"],"_bbp_reply_count":["3"],"_bbp_last_reply_id":["147931"],"_bbp_last_active_id":["147931"],"_bbp_last_active_time":["2021-03-24 15:37:24"]},"test":"arjunv"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/53625","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\/53625\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=53625"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}