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Old   June 27, 2012, 03:49
Default How to use values of a plane cutting the domain for inlet conditions?
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Dear all,

I have the case that I want to simulate a flow channel containing a combustion chamber in which I want to inject vaporized kerosene. The problem is that my computational ressources are quite limited. By now I have results for my flow channel without injecting anything. As I need a very fine mesh in the injection region (which leads to a big mesh), I want to cut my flow channel by a plane upstream the injection point and use these results from this plane as my inlet conditions for my case with injection and then just calculating this part.

By now I have no idea how I could manage this. Any help and suggestions are highly appreciated!

Best regards,
Stefan
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Old   June 27, 2012, 08:39
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Glenn Horrocks
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Have a look at the profile boundary condition option.
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Old   June 27, 2012, 10:05
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Thanks for your hint, Glenn. This is exactly what I was looking for.

But now I have problems Importing it. I performed the following steps:

First I created a plane in ANSYS CFX Post. Then I exported the data on this plane to a BC Profile. Afterwards I started CFX Pre and wanted to Import it, but it crashes everytime.

I exported data for all variables except of that for heat flux.

Any idea what could be the reason?
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Old   June 27, 2012, 10:22
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Peter Galimutti
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in the cfd post go to file--> export--> velocity & other variables required at the plane.

you should be able to get a .csv file with physical co-ordinates and their corresponding variable values.

i don't remember importing, but i'll post the rest after i get accesss to CFX.

but if this is what you have done ignore it!
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Old   June 27, 2012, 10:26
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Dear Peter,

this is exactly what I did, but I want to export values for all variables. So I chose costum export and not total pressure or velocity option for export as with this options it is only possible to export a part of the variables.

But with this custom option CFX Pre crashes when I want to import my file.

When I choose total pressure option instead it works fine, but as I wrote I would like to have tha values for all variables.
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Old   June 27, 2012, 10:39
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you just need velocity or pressure and thermal bcs for initialization.

if it crashes it may be due to systems limited resources as you mentioned earlier.


Probably what you can do is give initial condition in 'Initial value specification' in the 'Solver Manager'. All you need to do is use the previous result file. however it may warn you that the initial mesh is not matching the new mesh, but it's alright, the values get interpolated.

HTH

Last edited by p.galimutti; June 27, 2012 at 13:00.
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Old   June 28, 2012, 04:56
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As Inlet I want to use a total pressure bc, but if I just export and import the pressure and velocity values I will loose the turbulence, right?
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Old   June 28, 2012, 10:29
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Peter Galimutti
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then try the last step in my previous post. it will initialize all the data! it's pretty easy...this is the screenshot of how you can use previous results using solver manager
Attached Images
File Type: jpg solver_manager.jpg (38.6 KB, 11 views)

Last edited by p.galimutti; June 28, 2012 at 12:51.
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Old   July 2, 2012, 05:08
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But the problem is, that in the combustion chamber the flow is completely subsonic, but if I interpolate the results from the whole flow channel, also the supersonic region in the flow channel will be taken into account, right?
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Old   July 3, 2012, 09:05
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Another question:

I have the problem that my y coordinate in the case from which I want to export the values of the plane differs from these I want to import them as my inlet boundary condition. Is it possible to make a coordinate transformation when I want to import the values?
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