{"id":395731,"date":"2024-11-29T10:05:56","date_gmt":"2024-11-29T10:05:56","guid":{"rendered":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/tracer-mixing-in-stirred-tank-passive-scalar-transport\/"},"modified":"2024-11-29T10:05:56","modified_gmt":"2024-11-29T10:05:56","slug":"tracer-mixing-in-stirred-tank-passive-scalar-transport","status":"publish","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/tracer-mixing-in-stirred-tank-passive-scalar-transport\/","title":{"rendered":"Tracer Mixing In Stirred Tank (Passive Scalar Transport)"},"content":{"rendered":"

<p>Hi,<\/p><p>I am simulating batch mixing in a stirred tank, injecting a small volume of tracer into a tank filled with water and tracking the concentration profile at several locations to get the mixing time. For this simulation, I am assuming the tracer doesn’t influence the flow field (same properties of bulk fluid) so I only need to solve one equation for the transport of tracer. I have followed the general steps in terms of setting up the simulation which include:<\/p><\/p>\n

    \n
  1. Solving steady state flow field using SST K-Omega with curvature correction.<\/li>\n
  2. Activate species transport and create mixture template for water-tracer. Tracer physical properties will be the same as water. Change diffusivity of tracer in water from default value (2.88e-05) to literature value 1.47e-09.<\/li>\n
  3. Switch off flow and turbulence equations, leaving only one equation for transport of tracer.<\/li>\n
  4. Patch small volume of tracer into computational domain near the top of the liquid (injection point was very close to the wall, 0.2 cm away).<\/li>\n
  5. Set up concentration probes at several locations in the tank.<\/li>\n
  6. Run simulation.<\/li>\n<\/ol>\n

    <p><\/p><p>When I run the simulation, I notice the mixing behaviour in the tank appears to be physically unrealistic where there are heavy fluctuations observed at all the monitoring locations (there should only be some fluctuations near the point of injection). Here are two plots, one near the bottom of the tank (0.04 m) and one near the point of injection (0.10 m). Both monitors give severe fluctations<\/p><p> <\/p><p><\/p><p><\/p><p>I am unsure as to what is causing this issue. For comparison I ran another simulation using the steady state profile from standard k-epsilon as opposed to SST k-omega with curvature correction and found a more reasonable profile behaviour (see profiles below). What possible reasons could there be for the degradation of SST K-Omega with curvature correction predictions and how can I resolve this to get a more physically realistic profile?<\/p><p><\/p><p><\/p><\/p>\n","protected":false},"template":"","class_list":["post-395731","topic","type-topic","status-publish","hentry"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_bbp_forum_id":["27792"],"_bbp_topic_id":["395731"],"_bbp_subscription":["282802","199"],"_bbp_author_ip":["129.11.113.4"],"_bbp_reply_count":["7"],"_bbp_reply_count_hidden":["0"],"_bbp_voice_count":["2"],"_bbp_engagement":["282802","199"],"_btv_view_count":["240"],"_bbp_topic_status":["unanswered"],"_bbp_last_reply_id":["395766"],"_bbp_last_active_id":["395766"],"_bbp_last_active_time":["2024-11-29 13:29:02"]},"test":"ll17s5rleeds-ac-uk"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/395731","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\/395731\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=395731"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}