{"id":435199,"date":"2025-06-24T04:26:37","date_gmt":"2025-06-24T04:26:37","guid":{"rendered":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/cannot-access-surface-nusselt-number-as-output-parameter-in-workbench\/"},"modified":"2025-06-24T04:26:37","modified_gmt":"2025-06-24T04:26:37","slug":"cannot-access-surface-nusselt-number-as-output-parameter-in-workbench","status":"publish","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/cannot-access-surface-nusselt-number-as-output-parameter-in-workbench\/","title":{"rendered":"Cannot Access ‘Surface Nusselt Number’ as Output Parameter in Workbench"},"content":{"rendered":"

<p>Hello there, I’m recreating the work from a video tutorial which I’ve found in YouTube to link Ansys Workbench to MATLAB using journal files. I’ve followed the video until 3:44, but right there, I couldn’t see the variable ‘Surface Nusselt Number’ in the Variable Selector to use inside areaAve(Surface Nusselt Number)@walls in CFD-Post for the ‘Results’ component system (I’m using Ansys 2024 R2). I’ve searched the web & prompted ChatGPT for a solution. After I’ve initaialized the solution in Ansys Fluent, I’ve even selected all of the options in ‘Sampling Options…’, and in ‘Sampling Options (Zone Selection)…’ I was able to select select ‘Surface Nusselt Number’ in ‘Wall Fluxes…’ and I’ve selected it for the Zone ‘walls’ like I’ve interpreted from the video (as shown in the 1st pic).<\/p><p>how to link ANSYS Workbench TO MATLAB Using Journal Files ??? – YouTube<\/a><\/p><p> <\/p><p>\"\"<\/p><p>but when I proceed to the later stages of the video in CFD-Post (corresponding to the same WorkBench Project), as I said I couldn’t find the ‘Surface Nusselt Number’ in the Variable Selector. Even, if I try to manually type it the formula for the expression, I’m meeting errors like this: \"\"<\/p><p>So, then from ChatGPT’s suggestion, I’ve exported the solution data from Fluent as shown below in a .CDAT file to manually process it in a new CFD-Post Window:<\/p><p>\"\"<\/p><p>Now I can open this .CDAT file in CFD-Post and compute the value of the variable ‘nusselt number’ (which matches exactly with the YT video), but I can’t link this expression to be a Workbench output parameter (like I have to, to follow the next steps in the video)\"\"<\/p><p>Context: I need to link up DesignModeler parameters for optimisation from their hydrodynamic response from AQWA, the optimization part is to be done in python\/MATLAB, where I’m supposed to develop a new algo. for design optimisation as my research. I’m new to Ansys Products, I’ve never used Fluent or CFD-Post before, I need to link up AQWA to either python\/MATLAB to backpropagate the outputs to iterate over designmodeler parameters to find the configuration which optimes my objective function (which is not a direct output from AQWA, but I have to calculate it using AQWA’s outputs and some computing using python\/MATLAB and my guide suggested me this video for reference.<br><br>P.S. I’m ok, with not being able to complete this Fluent example (due to technical incompatibilities\/redundancies in the software), please help me resolve my issue for linking the Workbench, AQWA & either python\/MATLAB for my research quest. I’ve tried for weeks to months, I’ve contracted experienced people like professors, researchers & other forums, but I couldn’t figure things out (that too as a beginner, who’s gonna have a very short duration of access to these softwares as an intern, where I’m expected to publish my research, which ends within a week).<br><br>Once again, Thank you so much from the bottom of my heart. Your help in having me figure out these software linkages would be invaluable to my research.<\/p><p>Kodidasu Viveka Siva Surya Teja<\/p><\/p>\n","protected":false},"template":"","class_list":["post-435199","topic","type-topic","status-publish","hentry","topic-tag-ansys-fluent","topic-tag-aqwa","topic-tag-automation","topic-tag-cfd-post","topic-tag-fluent","topic-tag-fluent-cfd-post-1","topic-tag-journal-file","topic-tag-matlab","topic-tag-python"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_bbp_forum_id":["27796"],"_bbp_topic_id":["435199"],"_bbp_subscription":["496644","199"],"_bbp_author_ip":["203.110.247.87"],"_bbp_last_reply_id":["435230"],"_bbp_last_active_id":["435230"],"_bbp_last_active_time":["2025-06-24 09:54:09"],"_bbp_reply_count":["3"],"_bbp_reply_count_hidden":["0"],"_bbp_voice_count":["2"],"_bbp_engagement":["496644","199"],"_btv_view_count":["336"],"_bbp_topic_status":["unanswered"],"_edit_lock":["1750758382:496644"]},"test":"vspenergyofficialgmail-com"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/435199","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\/435199\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=435199"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}