{"id":280240,"date":"2023-04-19T06:16:27","date_gmt":"2023-04-19T06:16:27","guid":{"rendered":"\/forum\/forums\/topic\/set-boundary-conditions-between-air-and-water\/"},"modified":"2023-09-11T11:44:30","modified_gmt":"2023-09-11T11:44:30","slug":"set-boundary-conditions-between-air-and-water","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/set-boundary-conditions-between-air-and-water\/","title":{"rendered":"Set boundary conditions between air and water"},"content":{"rendered":"<p>Hi Fluids community,<br \/>I am building a 2D model to represent ambient temperature propagation in water and sediment of a pond. I have defined the air-water BC as &#8220;Convection&#8221; and hooked air-temperature time series to the &#8220;Free Stream Temperature&#8221; tap. Also, I assumed the Heat Transfer Coefficient to be 12 W\/m2K (please see below a snapshot of the air-water BC window). In my first case, I initialised the 2D model (pond) with an initial temperature equal to 5 C, as I test to easily distinguish the heat transfer from air to water (air temperature started at 26 C). However, I observed that water temperature declined at the air-water boundary (shown in the attached image). Questions:<br \/>1) Could please let me know if the BC configuration for this problem is correct?<br \/>2) I have changed units form K to C in Fluent and I imported air temperature time series in C as well. Wonder if the reason why the temperature at the air-water boundary is lower than 5 C is because I should import temperature in K units?<br \/>Thanks in advance.<\/p>\n<p>Figure 1. Air-water BC settings.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"\/forum\/wp-content\/uploads\/sites\/2\/2023\/04\/19-04-2023-1681884675-mceclip0.png\" width=\"623\" height=\"325\"><\/p>\n<p>Figure 2. Lower temperature at the air-water boundary after 1 min.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"\/forum\/wp-content\/uploads\/sites\/2\/2023\/04\/19-04-2023-1681884720-mceclip1.png\" width=\"901\" height=\"348\"><\/p>\n","protected":false},"template":"","class_list":["post-280240","topic","type-topic","status-closed","hentry"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_bbp_subscription":["224907","199","292887"],"_bbp_author_ip":["23.192.164.18"]," _bbp_last_reply_id":["0"]," _bbp_likes_count":["0"],"_btv_view_count":["829"],"_bbp_status":["publish"],"_bbp_topic_status":["unanswered"],"_bbp_topic_id":["280240"],"_bbp_forum_id":["27792"],"_bbp_engagement":["199","224907","292887"],"_bbp_voice_count":["3"],"_bbp_reply_count":["7"],"_bbp_last_reply_id":["306082"],"_bbp_last_active_id":["306082"],"_bbp_last_active_time":["2023-09-11 11:44:18"]},"test":"laureano-gonzalezresearch-usc-edu-au"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/280240","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\/280240\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=280240"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}