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April 16, 2014, 00:20 |
Question about Moving Mesh Modelling
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#1 |
Senior Member
Ashkan Javadzadegan
Join Date: Sep 2010
Posts: 255
Rep Power: 16 |
Dear All,
I am modelling flow in a tube with moving walls. As seen in the attached image, the middle part of tube starts to narrow from t = 0 to t = 1.0. I have done this part of modelling successfully. Now, I want to investigate the effect of time shift on the flow behaviour. I mean, I want to start modelling from t = t1 to t = 1+t1. I created the model of narrowing to t1 and then tried to model it; however, I’ve got overflow error. Is there any way to do the modelling from t = 0 to t = t1, and then use the narrowed geometry at t1 and run another simulation. Regards, AshtonJ |
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April 16, 2014, 05:50 |
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#2 |
Senior Member
Lance
Join Date: Mar 2009
Posts: 669
Rep Power: 22 |
Use your deformed geometry at t1 as initial condition for your next simulation. See that FAQ on what to do if you get overflow errors.
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April 16, 2014, 06:10 |
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#3 |
Senior Member
Ashkan Javadzadegan
Join Date: Sep 2010
Posts: 255
Rep Power: 16 |
Thanks Lance. Actually, I tried it. First, I defined a transient analysis from 0 to t1, then defined another analysis from t1 to 1. In configuration, I used the the first analysis as the initial condition for second analysis. However, when I checked the second analysis results, I realized that the initial geometry is the geometry at t=0 (non-constricted pipe) not t=t1. Do you have any idea where the poblem could be?
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April 16, 2014, 06:14 |
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#4 | |
Senior Member
Lance
Join Date: Mar 2009
Posts: 669
Rep Power: 22 |
Quote:
You need to make sure that you use the geometry from the initial file and not the input file. Under initial values specification, make sure that you have specified: "Use mesh from: initial values" |
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April 17, 2014, 04:21 |
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#5 |
Senior Member
Ashkan Javadzadegan
Join Date: Sep 2010
Posts: 255
Rep Power: 16 |
Thanks Lance, it works.
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April 17, 2014, 05:47 |
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#6 |
Senior Member
Ashkan Javadzadegan
Join Date: Sep 2010
Posts: 255
Rep Power: 16 |
Dear Lance,
I encountered with a strange problem. I defined two transient analyses, one from 0[s] to 0.25[s] (transient 1) and the other from 0.25[s] to 1.25[s] (transient 2). As suggested, I used the transient 1 mesh as initial condition for transient 2. However, I faced with a strange problem in transient 1 results. I attached here the wall deformation in transient 1 analysis at t=0.248[s] and t=0.25[s]. As seen, at 0.248[s], as instructed by the mesh displacement graph on the left, the middle section of pipe is narrowed. However, at t=0.25[s], the middle section of pipe is returned to its initial non-deformed state in contrast to its corresponding displacement graph shown on the left. I am confused with this, do you know why this happens? Thanks |
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