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find Cell Index via geometry coordinates

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Old   May 9, 2016, 04:38
Default find Cell Index via geometry coordinates
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Charles K.
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Hello everyone,

I know the xyz coordinates of a certain point in my model geometry and want to use these coordinates to get the nearest Cell Index in Open Foam. I looked through the Documentation in order to find an existing OF utility able to resolve my problem but found nothing.

I know that there is a function in OF called 'findCell' that extracts the index of a cell in a mesh. Unfortunately, I'm quite new to OpenFoam and have no Idea how to implement 'findCell' in an utility.

Does anyone have have an idea?


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Old   May 9, 2016, 22:10
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Kyle Mooney
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Heya,

Check out this thread and see if it helps you get started:
http://www.cfd-online.com/Forums/ope...-parallel.html

Cheers!
Kyle
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Old   May 10, 2016, 05:12
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Charles K.
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Hello Kyle and thanks for your answer and the link!

As a first step, i would like to know how utilities are created and executed in OFl, i've never done it before. Do I simply have to write the content of my own utility in a new text file, make the file executable and run it over the specific OF case?

Thanks for your help,

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Old   May 10, 2016, 14:14
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Kyle Mooney
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Hi Charles,

It really drastically depends on what it is you're trying to do...

A good place to start might be to go through the /applications/utilities folder and see if you find something that is already doing something roughly similar to what you're trying to accomplish. Try to understand whats its doing then try and adapt it from there.
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Old   September 17, 2016, 16:15
Default findNearestCell() tolerance
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Tarak
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Hi Kyle,

As you suggested, I have been using the function findNearestCell() (which belongs to the meshSearch class, http://openfoamcfd.sourceforge.net/d...eshSearch.html) inside my script to get the nearest cells to a series of points inside the boundary layer for flow over an airfoil. It seems the tolerance (tol_, which is a public variable of the class) is hard-coded to a value of 1e-3, which may not be sufficient for regions of very fine mesh. That is why I'm getting wrong results out of the function findNearestCell(). Have you ever faced this issue, and Is there any way to change this tolerance without recompiling?

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