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-   -   Extrapolated values from input coordinates (http://www.cfd-online.com/Forums/fluent/99364-extrapolated-values-input-coordinates.html)

peter_and_pan April 2, 2012 04:44

Extrapolated values from input coordinates
 
Hello,

I have a question and I didn't find an answer in the fluent documentation.

Is that possible to export values at specified coordinates (not necessarily on a grid node) in Fluent?

Thanks for your replies.

Peter

banty April 2, 2012 12:19

I think no.

LuckyTran April 2, 2012 21:10

Quote:

Originally Posted by peter_and_pan (Post 352622)
Hello,

I have a question and I didn't find an answer in the fluent documentation.

Is that possible to export values at specified coordinates (not necessarily on a grid node) in Fluent?

Thanks for your replies.

Peter

That is an interesting question:

I have exported data at individual points before by simply creating point surface monitors and just choosing any of the vertex schemes (minimum, average, maximum). If your surface is a single point, the three will be the same (since there is only 1 vertex). I have entered locations that do not correspond to the grid locations with no issues. However, I do not know what the mechanics are in Fluent for when the specified location is not exactly a grid node location. There may be some magic that Fluent uses to interpolate, or that it may pick the nearest vertex. I am not sure, but if all you care about is exporting data at a point, then I am sure it will work as I have done it many times. Again, I know for sure that I did not enter the exact cell locations. Who even knows what the exact locations are, all the way down to machine precision?

You can perhaps fool Fluent into interpolating by using a surface integral. For example, a area-weighted average, surface integral of a point, will be similar to a linear interpolation of the values at surrounding vertices. Just an idea.

I hope that answered your question, somewhat.

peter_and_pan April 3, 2012 03:39

Quote:

Originally Posted by LuckyTran (Post 352799)
That is an interesting question:

I have exported data at individual points before by simply creating point surface monitors and just choosing any of the vertex schemes (minimum, average, maximum). If your surface is a single point, the three will be the same (since there is only 1 vertex). I have entered locations that do not correspond to the grid locations with no issues. However, I do not know what the mechanics are in Fluent for when the specified location is not exactly a grid node location. There may be some magic that Fluent uses to interpolate, or that it may pick the nearest vertex. I am not sure, but if all you care about is exporting data at a point, then I am sure it will work as I have done it many times. Again, I know for sure that I did not enter the exact cell locations. Who even knows what the exact locations are, all the way down to machine precision?

You can perhaps fool Fluent into interpolating by using a surface integral. For example, a area-weighted average, surface integral of a point, will be similar to a linear interpolation of the values at surrounding vertices. Just an idea.

I hope that answered your question, somewhat.

Thank you for your reply.

I'm gonna try this solution and I let you know.

Peter

hhh August 23, 2012 05:10

coordinates doubt
 
2 Attachment(s)
Dear friends,
i am doing 3D wing analsysis by using gambit & fluent in gambit i selected the coordinates is +y view in gambit (ie x is towards right, y is towards horizontal wing & z is downwards,) see image 1 xyz coordinates, after i finished my meshing i import in fluent in that if i see grid in display option the coordinates its shows (x is towards right, y is vertical & z is horzontal) see image 2 xyz coordinates, how i can change my coordinates in fluent according my gambit coordinates, please find the attached images,

In gambit my wing looks towards bottom ie actual geometry, but in fluent its change, see wing& xyz coordinates closely in both images,please help me


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