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Hi,<br>
Because I had to compute flow rate across sections, torque values on
body surfaces, etc, I have developed a filter called
vtkIntegrateVariables which performs a discrete integration of a
variable field (define on points of an unstructured mesh) over a
surface. I give you an example of the way it works for a flow rate
computation:<br>
- extract the surface<br>
- generate normals <b>n</b><br>
- vtkCalculator: generate field <b>V</b>.<b>n </b>(where <b>V</b> is
the velocity vector)<br>
- integrate with the vtkIntegrateVariables filter<br>
<br>
The pipeline of the filter is the following:<br>
- check whether values are defined at points<br>
- pass values to cell (vtkPointDataToCellData)<br>
- loop over number of cells, compute cell_value*cell_area, sum<br>
- store the local integration values into an array<br>
- pass back to point data (vtkCellDataToPointData)<br>
- write the result (sum of the local integrations) into a file<br>
I have compared the results of torque and flow rate integration with
CFX5.7-Post and it gives extremely good results. I have used it for 3D
surface integration but it should work for 2D line. If you wish to use
it, please let me know and I will send it to you. An option for cell
data input has then to be added.<br>
I would be glad to contribute to paraview with this filter if needed.
In such a case I will modified it so that it can handle different kinds
of input data type. Just let me know.<br>
Theophane<br>
<br>
<pre class="moz-signature" cols="72">--
Theophane Foggia
CSCS - Swiss National Supercomputing Centre | Tel: +41 (91) 610.82.14
via Cantonale, 6928 Manno, Switzerland | Fax: +41 (91) 610.82.82</pre>
<br>
<br>
Ben Tay wrote:
<blockquote
cite="mid804ab5d40603130438rbd2fd76m7c9359cda4bb1a05@mail.gmail.com"
type="cite">
<div>hi,</div>
<div> </div>
<div>i need to compute lift/drag coefficient/force in 2d for flow
past cylinder/airfoil etc. my output data is single structured c-grid
with cell center velocities/pressure. I am trying to explore different
software to find out which is better. Has anybody tried using paraview.
Is it easy? thanks. </div>
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<br>
<br>
<pre class="moz-signature" cols="72">
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