{"id":29832,"date":"2018-07-27T21:05:11","date_gmt":"2018-07-27T21:05:11","guid":{"rendered":"\/forum\/forums\/topic\/surface-tension-issues\/"},"modified":"2018-07-27T21:05:11","modified_gmt":"2018-07-27T21:05:11","slug":"surface-tension-issues","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/surface-tension-issues\/","title":{"rendered":"Surface tension issues"},"content":{"rendered":"<p>I am running a simulation of oil droplets (high viscosity-machine oil and low viscosity-crude oil).. The oil droplets were injected into seawater about 20 cm below the surface. When they surfaced we then observed their evolution. I have added a figure to show what happens. The black lines are what we observed in the laboratory, the red lines are what we observed with Fluent.&nbsp; In both cases,&nbsp;the oil droplet would surface, expand a little, then contract. Then after about 0.5 to 1.5 seconds, the oil droplet would rapidly double in size. The simulations would never see this effect. I have added&nbsp;the information below&nbsp;with all relevant information. The surface tensions were the continuum surface stress (CSS) with implicit body forces.&nbsp; Any ideas on what might be wrong?<\/p>\n<p><\/p>\n<p>Air density = 1.225 kg m<sup>-3<\/sup><\/p>\n<p><\/p>\n<p>Air viscosity = 1.7894 10<sup>-5<\/sup> kg m<sup>-1<\/sup> s<sup>-1<\/sup><\/p>\n<p><\/p>\n<p>Water density = 1021.5 kg m<sup>-3<\/sup><\/p>\n<p><\/p>\n<p>Dynamic water viscosity = 0.00103 kg&nbsp;m<sup>-1<\/sup> s<sup>-1<\/sup><\/p>\n<p><\/p>\n<p>Crude oil density = 876.5 kg m<sup>-3<\/sup><\/p>\n<p><\/p>\n<p>Crude oil dynamic viscosity = 0.01 kg\/ms<sup><br \/><\/sup><\/p>\n<p><\/p>\n<p>Machine oil density 889.0 kg m<sup>-3<\/sup>.&nbsp;<\/p>\n<p><\/p>\n<p>Machine&nbsp;oil dynamic viscosity = 0.40 kg\/ms<\/p>\n<p><\/p>\n<p>Water-air surface tension&nbsp;= 0.072 N\/m<\/p>\n<p><\/p>\n<p>Crude oil &#8211; air surface tension = 0.028 N\/m<\/p>\n<p><\/p>\n<p>Machine oil &#8211; air surface tension = 0.032 N\/m<\/p>\n<p><\/p>\n<p>Crude oil &#8211; water surface tension = 0.019 N\/m<\/p>\n<p><\/p>\n<p>Machine oil &#8211; water surface tension = 0.040 N\/m<\/p>\n<p><\/p>\n<p>&nbsp;<\/p>\n","protected":false},"template":"","class_list":["post-29832","topic","type-topic","status-closed","hentry"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_bbp_old_topic_id":["2001"],"_bbp_old_topic_author_name_id":["Anonymous"],"_bbp_old_is_topic_anonymous_id":["false"],"_bbp_old_closed_status_id":["publish"],"_bbp_author_ip":[null],"_bbp_old_sticky_status_id":["normal"],"_bbp_likes_count":["0","0","0","0","0"],"_btv_view_count":["3514"],"_bbp_subscription":["236735"],"_bbp_topic_status":["unanswered"],"_bbp_status":["publish"],"_bbp_topic_id":["29832"],"_bbp_forum_id":["27792"],"_bbp_engagement":["25","199","22555","158003"],"_bbp_voice_count":["4"],"_bbp_reply_count":["27"],"_bbp_last_reply_id":["71765"],"_bbp_last_active_id":["71765"],"_bbp_last_active_time":["2018-12-07 23:51:38"]},"test":"soloviev"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/29832","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\/29832\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=29832"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}