CFD Online Discussion Forums (https://www.cfd-online.com/Forums/)
-   OpenFOAM (https://www.cfd-online.com/Forums/openfoam/)
-   -   Validation Study: How do I plot wind tunnel data (*.dat) in Paraview (https://www.cfd-online.com/Forums/openfoam/91051-validation-study-how-do-i-plot-wind-tunnel-data-dat-paraview.html)

 bigbang July 28, 2011 14:33

Validation Study: How do I plot wind tunnel data (*.dat) in Paraview

I'm new to CFD openFOAM so I'm running through a validation case to sharpen my skills.

The windtunnel data for the Ahmed Body is taken from here

The *.dat files contain data points for given planes. How to I plot them and interpolate it over the plane to compare my results to the windtunnel?

 bigbang August 3, 2011 10:27

1 Attachment(s)
Update:

Ok I managed to import the data after cleaning it up a little in excel and saving it as a CSV file (comma delimited)

Paraview can open CSV files as a table. Then I applied the Filter > TableToPoints to get points. However I wasn't able to see them until I clicked on the split "horizontal button" on the right and chose a 3D view.

Now I have the points where I want them, but I can't manage to get a surface from the points. Any ideas?

 bigbang August 4, 2011 14:15

matlab to the rescue

1 Attachment(s)
OK so I finally managed to get a surface from my points.

Unfortunately it was not by means of free software. I used matlab to interpolate the points over a structured grid and then plotted the result. First you must load your data into matlab under 3 arrays. I used 'x', 'y' and 'z'. Where x and y were the coordinates and z was the magnitude of the velocity.

Code:

```ti = -250:1:250; tj = 28:1:538; [qx,qy] = meshgrid (ti,tj); F = TriScatteredInterp(x,y,z); qz = F(qx,qy); R = maprasterref(); mapshow(qz, R, 'DisplayType', 'surface');```
And after adjusting the plot using plotting tools you can see the attached result.

 akidess August 5, 2011 03:30

Alex, have you tried the TableToStructuredGrid filter instead of TableToPoints?

 bigbang August 5, 2011 08:00

2 Attachment(s)
Yes. Unfortunately I get a long error message about the number of rows.

I imported my data from CSV and it all comes in clean with the headers. There are 911 datapoints.

Then I select the TableToStructuredGrid filter and enter the range of my data and select the columns for x, y and z coordinates:
x {0,0}
y {-250,250}
z {28, 538}

I apply and get the following error:

Code:

```ERROR: In /home/opencfd/OpenFOAM/ThirdParty-2.0.0/ParaView-3.10.1/VTK/Graphics/vtkTableToStructuredGrid.cxx, line 97 vtkPTableToStructuredGrid (0x2621f90): The input table must have exactly 256011 rows. Currently it has 911 rows. ERROR: In /home/opencfd/OpenFOAM/ThirdParty-2.0.0/ParaView-3.10.1/VTK/Filtering/vtkExecutive.cxx, line 756 vtkPVCompositeDataPipeline (0x2623220): Algorithm vtkPTableToStructuredGrid(0x2621f90) returned failure for request: vtkInformation (0x26ccb40)   Debug: Off   Modified Time: 82398   Reference Count: 1   Registered Events: (none)   Request: REQUEST_DATA   ALGORITHM_AFTER_FORWARD: 1   FROM_OUTPUT_PORT: 0   FORWARD_DIRECTION: 0 ERROR: In /home/opencfd/OpenFOAM/ThirdParty-2.0.0/ParaView-3.10.1/VTK/Graphics/vtkTableToStructuredGrid.cxx, line 97 vtkPTableToStructuredGrid (0x2621f90): The input table must have exactly 256011 rows. Currently it has 911 rows. ERROR: In /home/opencfd/OpenFOAM/ThirdParty-2.0.0/ParaView-3.10.1/VTK/Filtering/vtkExecutive.cxx, line 756 vtkPVCompositeDataPipeline (0x2623220): Algorithm vtkPTableToStructuredGrid(0x2621f90) returned failure for request: vtkInformation (0x26cc300)   Debug: Off   Modified Time: 85434   Reference Count: 1   Registered Events: (none)   Request: REQUEST_DATA   ALGORITHM_AFTER_FORWARD: 1   FROM_OUTPUT_PORT: 0   FORWARD_DIRECTION: 0 ERROR: In /home/opencfd/OpenFOAM/ThirdParty-2.0.0/ParaView-3.10.1/VTK/Graphics/vtkTableToStructuredGrid.cxx, line 97 vtkPTableToStructuredGrid (0x2621f90): The input table must have exactly 256011 rows. Currently it has 911 rows. ERROR: In /home/opencfd/OpenFOAM/ThirdParty-2.0.0/ParaView-3.10.1/VTK/Filtering/vtkExecutive.cxx, line 756 vtkPVCompositeDataPipeline (0x2623220): Algorithm vtkPTableToStructuredGrid(0x2621f90) returned failure for request: vtkInformation (0x26cc300)   Debug: Off   Modified Time: 85468   Reference Count: 1   Registered Events: (none)   Request: REQUEST_DATA   ALGORITHM_AFTER_FORWARD: 1   FROM_OUTPUT_PORT: 0   FORWARD_DIRECTION: 0 ERROR: In /home/opencfd/OpenFOAM/ThirdParty-2.0.0/ParaView-3.10.1/VTK/Graphics/vtkTableToStructuredGrid.cxx, line 97 vtkPTableToStructuredGrid (0x2621f90): The input table must have exactly 256011 rows. Currently it has 911 rows. ERROR: In /home/opencfd/OpenFOAM/ThirdParty-2.0.0/ParaView-3.10.1/VTK/Filtering/vtkExecutive.cxx, line 756 vtkPVCompositeDataPipeline (0x2623220): Algorithm vtkPTableToStructuredGrid(0x2621f90) returned failure for request: vtkInformation (0x26cc300)   Debug: Off   Modified Time: 85506   Reference Count: 1   Registered Events: (none)   Request: REQUEST_DATA   ALGORITHM_AFTER_FORWARD: 1   FROM_OUTPUT_PORT: 0   FORWARD_DIRECTION: 0 Warning: In /home/opencfd/OpenFOAM/ThirdParty-2.0.0/ParaView-3.10.1/VTK/Filtering/vtkDataObject.cxx, line 910 vtkTable (0x2549d40): Attempted to ShallowCopy from null.```

 All times are GMT -4. The time now is 15:00.