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Transient 1-way FSI with Ansys

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Old   February 19, 2017, 15:31
Default Transient 1-way FSI with Ansys
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Leo
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Hello everybody,

I am currently having some issues to perform a 1-way transient Fluid-Solid-Interaction.

I have simulated a flow inside a fuel cell with CFX and the simulation did really fine. I simulated 150 timesteps, from 0 to 15s, with a step size of 0.1 s. I can visualize it at "Results" in CFX and it seems plausible.

Now I would like to analyze the effects of my flow in the walls of the fuel cell. Specially Equivalent, normal and sheer stresses.

I imported the results of CFX into the Setup of "Transient Structural". I have now two major problems:

1. No matter what I do, it seems the program only import ONE single time step from CFX. See Figure A attached.

2. At "Analysis Settings" I choose different numbers for "Number of Steps" (ideally I would like to have 150 too, like CFX), but I am not sure about what "Minimum Time Step" and "Maximum Time Step" mean. It seems, I am only allowed to repeat at them what I previously inserted at "Step End Time". So, I would like to know, what is it exactly about. See Figure B attached.

What am I doing wrong? Am I not modeling the problem in a proper way? Am I misunderstanding the use of a FSI here?
I really appreciate for your help. Thank you in advance.
Attached Images
File Type: png FigureA.PNG (21.5 KB, 33 views)
File Type: png FigureB.PNG (10.2 KB, 36 views)
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Old   February 20, 2017, 04:13
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Why just dont you turn auto time stepping off, type in 1 and use direct coupling?
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Old   February 20, 2017, 05:36
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Hello,
Thank you for your help. Yes, it seems to work.
Now about the Question 1 (my biggest problem actually), do you have any idea?
I need to import at least 15 (better 150) pressure loads but I all get is 1. (Figure A)
Thank you in advance.
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Old   May 23, 2017, 15:49
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Khiew Chee Keong
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Quote:
Originally Posted by LeandroGSS View Post
Hello,
Thank you for your help. Yes, it seems to work.
Now about the Question 1 (my biggest problem actually), do you have any idea?
I need to import at least 15 (better 150) pressure loads but I all get is 1. (Figure A)
Thank you in advance.
Hi LeandroGSS, have you solve your question 1? I am facing the same problem right now when I link my fluent solution to transient structural.
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Old   December 13, 2018, 01:16
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Siva Teja Golla
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Hi LeandroGSS,

Have you solved your first problem... I am facing the same problem too...
I am using Fluent + Transient mechanical... If you solved it, please let me know...
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Old   December 13, 2018, 05:49
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Quote:
Originally Posted by Siva Teja Golla View Post
Hi LeandroGSS,

Have you solved your first problem... I am facing the same problem too...
I am using Fluent + Transient mechanical... If you solved it, please let me know...
Basically the 1way FSI is the main problem. In my case, the the deflection / deformation is to big and thus the 1way FSI fails to model the case correctly. So perhaps just add a System Coupling module and drag your mechanical and fluent setups on this. Its quite straight forward...
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Old   December 18, 2018, 05:17
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A CFD post macro vas needed for multiple FSI timestep data transfers in the past, I don't know if something better exists jet.
Map is named:
ACT_FSI-Transient_V170.3

and it includes:
FSI_Transient_Export_Vol
FSI_Transient_Export_Surf
CFX_FSI_IORead
CFX_FSI_IOWrite
and instructions on how to use it


it works like a charm
i got it from the ansys site and it is free so I can share it. This is the link to my drive:
https://drive.google.com/open?id=15K...Ub3a6y0HAvnaA7
I am not sure if it works on newer versions of Ansys as I haven't used it for quite a while but I think it should as it is a macro
I was using it for transfer of volume temperatures

Last edited by urosgrivc; December 19, 2018 at 01:58.
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