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Gert-Jan van der Gulik September 4, 2000 09:08

Line information
Hi all,

Using CFX4.2, I want to know the average temperature over an arbitrary line in space (i.e. the average temperature between points x1,y1,z1 and x2,y2,z2). As I have 8 different cases and 98 different lines, there is a lot of work to be done and I want to do it as efficient as possible.

Which Post-processing program do you think is most efficient in performing this tedious work? Any suggestion?

I have checked the USERfortran routines but, as far as I know, there is no fancy routine to use. Does anyone have a routine or some tips and tricks to share?

Many thanks in advance,

Gert-Jan van der Gulik

Jan Rusås September 4, 2000 10:13

Re: Line information
Hi Gert-Jan,

I do not know if this solution is the most efficient, but anyway here it come.

You can use CFX-analyse

You must create a new region in the region manager,

Select physical and line, you can then define your line by x,y,z

It might be convenient to rename the line so it is easier to select the many different lines you are dealing with. You may copy this 'line' to another one and then adjust the x,y,z data and by that defining all your lines, or it might be more easy to change the data in the visualisation manager, it is up to you.

In the visualisation manager, you then select f.x. xy-graph and then the appropriate 'line' and scalar and write the data to a file.

The good thing about analyse is that you can define all your plots and then read in a new dump file and then just apply on each plot, he data will then be updated.

Regards Jan

Gert-Jan van der Gulik September 4, 2000 11:19

Re: Line information
Dear Jan,

Thanks for the quick reply but I can't find CFX-Analyse. I think CFX-Analyse is a MS-Windows-version feature that I don't use. We only have CFX-Visualise, CFX-view, Visualise-linegrapher and Linegraph. Probably I can use Visualise-linegrapher but yet I haven't figured out how it works.

Regards, Gert-Jan

Budi September 4, 2000 11:45

Re: Line information
Hi Gert,

It's me ;-) CFX-Analyse is a additional post-processor for CFX4.3 and later. IMO it's a better post-processor than visualiser. I don't know if it's available for Windows version but I'm sure AEAT has a SUN version. I have tried it on our SUN for a limited time and I can say.. I like it.


Jan Rusås September 5, 2000 03:10

Re: Line information
Hi again Gert Jan,

I can not help you with Visualise and linegraph is for viewing data in a file already written by e.g. view. I do not know if Visualise-linegrapher is for the same purpose.

You can also create line data in view, but it is not so efficient as in analyse.

You should go to the define line window, there you define the line in physical space x,y,z. Go to write data- there you can select all variables or a single and select and file name. Note you can increase the number of points in one of the pop-up windows in the initializing, look out for maximum number of cells in a line. The problem with view is, it is not a efficient way of doing this, you have to define all your lines for each dump file, no information about the lines are saved when you read in a new dump file.

I do think you should try and see if Visualise could solve your problem, I also think, depending on how complicated you structure is, you should use user fortran for writing your data. If the line data you want does not fit with cell centres or faces the tricky part is only the interpolation.

Regards Jan

Jan Rusås September 14, 2000 03:58

Re: Line information
Dear Gert-Jan,

Just for your information, Line graph data is available through the command file in CFX4.3. An upgrade will very simple solve your problem.

Regards Jan

Gert-Jan van der Gulik September 18, 2000 03:17

Re: Line information

'line graph data' was already available in CFX-4.2 and will only give temperature at a single point as a function of iteration or timestep (as far as I know). I don't see how this would provide an average temperature between (x1,y1,z1) and (x2,y2,z2).

Still looking for the most efficient route............................................. ............................Regards, Gert-Jan

Jan Rusås September 18, 2000 03:36

Re: Line information
Dear Gert,

My mistake, You are right line graph is only for a point, it should be named point graph. Several points will give you a line!, which you can average. Have you checked if it is possible in patch data to define a line. You should be able to use user fortran for your problem, i.e. usrsrc, as already mentioned. Depending on the structure of your mesh the only tricky part is the interpolation, which on the other hand is not so difficult.

Regards Jan

Gert-Jan van der Gulik September 18, 2000 03:53

Re: Line information
Dear Jan,

I know I should put some effort in userfortran but don't have the time as I have to write my PhD-thesis. For this thesis I need some average temperatures that should be very easy to get using CFX, but ........... well, you already know. I am also convinced there is someone out there in the world that faced the problem before. I don't see why I should re-event the wheel.

When I have the time I will write the fortran code and come back on this topic.... Anyway, thanks for the suggestion on CFX-Analyse. This programs helps, a little.

Regards, Gert-Jan

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