{"id":304708,"date":"2023-09-03T17:45:37","date_gmt":"2023-09-03T17:45:37","guid":{"rendered":"\/forum\/forums\/topic\/fluent-pressure-problem-v2\/"},"modified":"2023-09-03T17:45:37","modified_gmt":"2023-09-03T17:45:37","slug":"fluent-pressure-problem-v2","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/fluent-pressure-problem-v2\/","title":{"rendered":"Fluent pressure problem v2"},"content":{"rendered":"

Hi all.<\/span><\/span><\/span><\/p>\n

I’m simulating the rotation of a wheel with water pressure using 6DOF.<\/span><\/span> Previously, I made a test model with one wheel, at the inlet I had a flow rate of 1 l\/s at the outlet atm pressure and at the second inlet atm pressure.<\/span><\/span> The wheel turned and sucked water from the entrance and from the second entrance.<\/span><\/span> Everything was ok.<\/span><\/span><\/span><\/p>\n

Previous post links:<\/span><\/span><\/span><\/p>\n

\/forum\/forums\/topic\/connecting-the-wheel-into-one-piece-fluent\/<\/span><\/span><\/span><\/p>\n

\/forum\/forums\/topic\/the-pump-wheel-does-not-rotate-in-the-fluent-dynamic-grid\/<\/span><\/span><\/span><\/p>\n

Then I complicated the task, I increased the wheel, added more blades on top and inside. All settings are similar, because the task remains the same as in the first option. The boundary conditions have changed, now at inlet 1 the flow rate is 2 l\/s, at the outlet the pressure is 12 MPa, and at the second inlet (inlet 2)  the pressure is 4 MPa. I need the wheel to spin and take water from port 2. I need to see if this will work.<\/span><\/span><\/span><\/p>\n

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I made a good grid, it is 7 million cells, while the skewness is 0.88.<\/span><\/span><\/span><\/p>\n

SST model. Simple method.<\/span><\/span><\/span><\/p>\n

But when I run the task, I immediately see repeated 6DOF has not converged warnings.<\/span><\/span> <\/span><\/p>\n

I believe that the problem is in the second input 4 MPa.<\/span> Then I decided to check and put 12 MPa there as well as at the outlet.<\/span> I constantly see repeated 6DOF has not converged warnings right away.<\/span><\/span><\/span><\/p>\n

I waited until all pressure and flow graphs would equalize, as well as the moment on the rotating wheel would be equal to 0. But this did not happen, the oscillations continue. Then I stopped the calculation and again made the pressure at the second inlet 4 MPa. The fluctuations continued only at another level of the chart and the 6DOF has not converged warnings continue.<\/span><\/span><\/span><\/p>\n

Scr:<\/span><\/span><\/span><\/p>\n

1600 iterations at 12 MPa inlet (2) pressure:<\/span><\/span><\/span><\/p>\n

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Next, I set the pressure at inlet 2 with a size of 4 MPa, as I needed initially.<\/span><\/span><\/span><\/p>\n

Scr:<\/span><\/span><\/span><\/p>\n

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How to fix it? How to deal with fluctuations? Their amplitude is very large (see pictures).<\/span><\/span><\/span><\/p>\n","protected":false},"template":"","class_list":["post-304708","topic","type-topic","status-closed","hentry"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_bbp_subscription":["257647","8124","199"],"_bbp_author_ip":["168.143.243.24"]," _bbp_last_reply_id":["0"]," _bbp_likes_count":["0"],"_btv_view_count":["723"],"_bbp_topic_status":["unanswered"],"_bbp_status":["publish"],"_bbp_topic_id":["304708"],"_bbp_forum_id":["27792"],"_bbp_engagement":["199","8124","257647"],"_bbp_voice_count":["3"],"_bbp_reply_count":["8"],"_bbp_last_reply_id":["306765"],"_bbp_last_active_id":["306765"],"_bbp_last_active_time":["2023-09-14 07:34:30"]},"test":"javat33489gmail-com"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/304708","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\/304708\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=304708"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}