{"id":368142,"date":"2024-05-22T20:59:56","date_gmt":"2024-05-22T20:59:56","guid":{"rendered":"\/forum\/forums\/topic\/convective-augmentation-factor-in-define_heat_flux\/"},"modified":"2024-05-22T20:59:56","modified_gmt":"2024-05-22T20:59:56","slug":"convective-augmentation-factor-in-define_heat_flux","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/convective-augmentation-factor-in-define_heat_flux\/","title":{"rendered":"Convective Augmentation Factor in DEFINE_HEAT_FLUX"},"content":{"rendered":"<p>In Fluent 2023R2 User&#8217;s Guide (section 7.4.15.5.6. Augmented Heat Transfer), the Convective Augmentation Factor CAF is defined as&nbsp;CAF = Nu_measured \/ Nu_ideal_flow.<\/p>\n<p>In Fluent&#8217;s Customization Manual (section 2.3.20.2) the DEFINE_HEAT_FLUX macro, which uses the CAF, is described and the diffusion component of the heat flux (<strong>qid<\/strong>) is computed as <strong>qid = cid[0] + caf_fac*(cid[1]*C_T(c0,t0) &#8211; cid[2]*F_T(f,t)) &#8211; cid[3]*pow(F_T(f,t),4)<\/strong>, where<\/p>\n<ul>\n<li><strong>cid <\/strong>is a coefficient array<\/li>\n<li><strong>caf_fac <\/strong>is the CAF<\/li>\n<li><strong>C_T <\/strong>is the cell temperature<\/li>\n<li><strong>F_T <\/strong>is the face temperature<\/li>\n<\/ul>\n<p>It is unclear to me:<\/p>\n<ul>\n<li>why the diffusive heat flux is linearised in that way (in particular,&nbsp;why is there a power term?)<\/li>\n<li>why the CAF is applied to the &#8220;variable part&#8221; of the heat flux and not to the entire heat flux. Is it because a convective heat flux is necessarily a function of temperature, and therefore only the variable part of the <strong>qid<\/strong> is the one related to convection (and thus the only one that needs to be augmented by the CAF)?<\/li>\n<\/ul>\n","protected":false},"template":"","class_list":["post-368142","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=\"In Fluent 2023R2 User&#039;s Guide (section 7.4.15.5.6. Augmented Heat Transfer), the Convective Augmentation Factor CAF is defined as CAF = Nu_measured \/ Nu_ideal_flow.In Fluent&#039;s Customization Manual (section 2.3.20.2) the DEFINE_HEAT_FLUX macro, which uses the CAF, is described and the diffusion component of the heat flux (qid) is computed as qid = cid[0] + caf_fac*(cid[1]*C_T(c0,t0) - cid[2]*F_T(f,t))\" \/>\n\t<meta name=\"robots\" content=\"max-image-preview:large\" \/>\n\t<link rel=\"canonical\" href=\"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/convective-augmentation-factor-in-define_heat_flux\/\" \/>\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=\"Convective Augmentation Factor in DEFINE_HEAT_FLUX | Ansys Learning Forum\" \/>\n\t\t<meta property=\"og:description\" content=\"In Fluent 2023R2 User&#039;s Guide (section 7.4.15.5.6. Augmented Heat Transfer), the Convective Augmentation Factor CAF is defined as CAF = Nu_measured \/ Nu_ideal_flow.In Fluent&#039;s Customization Manual (section 2.3.20.2) the DEFINE_HEAT_FLUX macro, which uses the CAF, is described and the diffusion component of the heat flux (qid) is computed as qid = cid[0] + caf_fac*(cid[1]*C_T(c0,t0) - cid[2]*F_T(f,t))\" \/>\n\t\t<meta property=\"og:url\" content=\"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/convective-augmentation-factor-in-define_heat_flux\/\" \/>\n\t\t<meta property=\"article:published_time\" content=\"2024-05-22T20:59:56+00:00\" \/>\n\t\t<meta property=\"article:modified_time\" content=\"2024-05-22T20:59:56+00:00\" \/>\n\t\t<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n\t\t<meta name=\"twitter:title\" content=\"Convective Augmentation Factor in DEFINE_HEAT_FLUX | Ansys Learning Forum\" \/>\n\t\t<meta name=\"twitter:description\" content=\"In Fluent 2023R2 User&#039;s Guide (section 7.4.15.5.6. Augmented Heat Transfer), the Convective Augmentation Factor CAF is defined as CAF = Nu_measured \/ Nu_ideal_flow.In Fluent&#039;s Customization Manual (section 2.3.20.2) the DEFINE_HEAT_FLUX macro, which uses the CAF, is described and the diffusion component of the heat flux (qid) is computed as qid = cid[0] + caf_fac*(cid[1]*C_T(c0,t0) - cid[2]*F_T(f,t))\" \/>\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\\\/convective-augmentation-factor-in-define_heat_flux\\\/#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\\\/convective-augmentation-factor-in-define_heat_flux\\\/#listItem\",\"name\":\"Convective Augmentation Factor in DEFINE_HEAT_FLUX\"},\"previousItem\":{\"@type\":\"ListItem\",\"@id\":\"https:\\\/\\\/innovationspace.ansys.com\\\/forum#listItem\",\"name\":\"Home\"}},{\"@type\":\"ListItem\",\"@id\":\"https:\\\/\\\/innovationspace.ansys.com\\\/forum\\\/forums\\\/topic\\\/convective-augmentation-factor-in-define_heat_flux\\\/#listItem\",\"position\":3,\"name\":\"Convective Augmentation Factor in DEFINE_HEAT_FLUX\",\"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\\\/convective-augmentation-factor-in-define_heat_flux\\\/#webpage\",\"url\":\"https:\\\/\\\/innovationspace.ansys.com\\\/forum\\\/forums\\\/topic\\\/convective-augmentation-factor-in-define_heat_flux\\\/\",\"name\":\"Convective Augmentation Factor in DEFINE_HEAT_FLUX | Ansys Learning Forum\",\"description\":\"In Fluent 2023R2 User's Guide (section 7.4.15.5.6. Augmented Heat Transfer), the Convective Augmentation Factor CAF is defined as CAF = Nu_measured \\\/ Nu_ideal_flow.In Fluent's Customization Manual (section 2.3.20.2) the DEFINE_HEAT_FLUX macro, which uses the CAF, is described and the diffusion component of the heat flux (qid) is computed as qid = cid[0] + caf_fac*(cid[1]*C_T(c0,t0) - cid[2]*F_T(f,t))\",\"inLanguage\":\"en-US\",\"isPartOf\":{\"@id\":\"https:\\\/\\\/innovationspace.ansys.com\\\/forum\\\/#website\"},\"breadcrumb\":{\"@id\":\"https:\\\/\\\/innovationspace.ansys.com\\\/forum\\\/forums\\\/topic\\\/convective-augmentation-factor-in-define_heat_flux\\\/#breadcrumblist\"},\"datePublished\":\"2024-05-22T20:59:56+00:00\",\"dateModified\":\"2024-05-22T20:59:56+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":"Convective Augmentation Factor in DEFINE_HEAT_FLUX | Ansys Learning Forum","description":"In Fluent 2023R2 User's Guide (section 7.4.15.5.6. 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Augmented Heat Transfer), the Convective Augmentation Factor CAF is defined as CAF = Nu_measured \/ Nu_ideal_flow.In Fluent's Customization Manual (section 2.3.20.2) the DEFINE_HEAT_FLUX macro, which uses the CAF, is described and the diffusion component of the heat flux (qid) is computed as qid = cid[0] + caf_fac*(cid[1]*C_T(c0,t0) - cid[2]*F_T(f,t))"},"aioseo_meta_data":{"post_id":"368142","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 16:41:08","updated":"2024-10-28 16:41:08","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\tConvective Augmentation Factor in DEFINE_HEAT_FLUX\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":"Convective Augmentation Factor in DEFINE_HEAT_FLUX","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/convective-augmentation-factor-in-define_heat_flux\/"}],"acf":[],"custom_fields":[{"0":{"_bbp_subscription":["303794","15180"],"_bbp_author_ip":["184.24.96.207"]," _bbp_last_reply_id":["0"]," _bbp_likes_count":["0"],"_btv_view_count":["1192"],"_bbp_topic_status":["unanswered"],"_bbp_topic_id":["368142"],"_bbp_forum_id":["27792"],"_bbp_engagement":["15180","303794"],"_bbp_voice_count":["2"],"_bbp_reply_count":["1"],"_bbp_last_reply_id":["374841"],"_bbp_last_active_id":["374841"],"_bbp_last_active_time":["2024-08-02 08:21:00"]},"test":"andrea1-pinardimail-polimi-it"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/368142","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\/368142\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=368142"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}