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Old   February 14, 2009, 11:31
Default Hello, i am new in openFoam
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Hello,

i am new in openFoam and i donŽt know how to identify and output the neighbours of a cell[i]!

Is it possible in openFaom?

I hope someone can help me!

Thanks and kind regards
Khaled
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Old   February 14, 2009, 14:52
Default Hi Khaled mesh.cellCell
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Hi Khaled

mesh.cellCells()[cellI] gives the neighbours of cell cellI

su junwei
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Old   February 15, 2009, 05:58
Default Hi su junwei, thanks very m
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Hi su junwei,

thanks very much.

And with "Info<< mesh.cellCells()[celli]<< endl;" I put out the neighbours of celli?

Regards,
Khaled
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Old   February 15, 2009, 06:16
Default Yes, Khaled, you can print the
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Yes, Khaled, you can print them out. This is a list of cell index in the neighbourhood.
Junwei
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Old   February 15, 2009, 06:30
Default Thanks Su. IŽll try it now.
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Thanks Su. IŽll try it now.

Btw. do you know how to integrate over a special patch or is it possible with openfoam?

Thanks and regards
khaled
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Old   February 15, 2009, 06:41
Default Hi Khaled patchIntegra
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Hi Khaled

patchIntegrate can be used to integrate over a special patch, you can use it like this

patchIntegrate fieldname patchname.

This is a postprocessing utility.

Junwei
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Old   February 15, 2009, 07:07
Default Hi Su Junwei, oh ok, thanks
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Hi Su Junwei,

oh ok, thanks.

But mybe i hope you ask my last question here.

Exactly i want to integrate over the patch "outlet" of the pressure field "p". So then i only write

patchIntegrate p [1]

if the patchname is [1]?

Thanks,
Khaled
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Old   February 15, 2009, 14:19
Default Hi khaled yes. That's Ok.
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Hi khaled
yes. That's Ok. Just test it.
Junwei
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Old   June 2, 2010, 11:24
Default number of cell neighbours
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Hi Su,

Thanks for the hint, it was very helpful. I was wondering if there is a command to find the number of cell neighbours for a cell.

mesh.cellCells()[cellI] gives <no. of neighbouring cells>(<neighbours>)

If I want just the <no. of neighbouring cells> alone, how do I get it ?

Thanks.
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Old   June 6, 2010, 02:04
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Hi Ritu

Just using the size function like this
label neighbourCount=mesh.cellCells()[cellI].size()

sorry for late response
Junwei
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Old   November 16, 2010, 17:31
Default closest cell from point
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Hi Su Junwei and Khaled,

Does anyone know how to select the closest cell near the point (x,y,z)?

Thank you,

Pascal
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Old   November 17, 2010, 01:16
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Hi Pascal
you can use the following code

meshSearch ms(mesh);
label nearestCellIndex = ms.findNearestCell(p);

p is your point for searching nearest cell. nearestCellIndex is the cell index that you want.
Don't forget to include "meshSearch.H"

Junwei
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Old   November 17, 2010, 02:58
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Hi Pascal,

alternatively you can use

label labelOfClosestCell mesh.findCell(c y z);


Best Kathrin
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Old   December 9, 2010, 10:38
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Hi

I was looking in the forum and I hope you might help me?

I want to identify cells whose face(s) are in a patch and give them a value

what would it the the best way ?

Thanks


O. R.
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Old   December 9, 2010, 17:33
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Hi everybody,

I am trying to model a free turbulent jet with LES. In part of my project I have to determine value of some variables along a specific line inside my domain to compare my results with my refrences results but I dont know how I can do that?
I would appreciate any help.

best regards,
Yashar
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Old   December 10, 2010, 09:42
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Quote:
Originally Posted by yashar.afarin View Post
Hi everybody,

I am trying to model a free turbulent jet with LES. In part of my project I have to determine value of some variables along a specific line inside my domain to compare my results with my refrences results but I dont know how I can do that?
I would appreciate any help.

best regards,
Yashar
Just use sample tool in OpenFOAM. see Openfoam's user's guide
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Old   December 10, 2010, 09:45
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Quote:
Originally Posted by arkangel View Post
Hi

I was looking in the forum and I hope you might help me?

I want to identify cells whose face(s) are in a patch and give them a value

what would it the the best way ?

Thanks


O. R.

Just use faceCells in polyPatch class.

faceCells give you the index of a cell who owns the current patch face.

Regards, Junwei
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Old   December 10, 2010, 13:14
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Quote:
Originally Posted by su_junwei View Post
Just use sample tool in OpenFOAM. see Openfoam's user's guide
Hi Su,

thank you very much for your response.
indeed, I want to compute my jet width along the jet centreline. for that reason, I have to determine the centreline velocity(u(x,0,0)) that is function of x-axis then compute distance from jet centreline in y-direction where the x component of velocity become half of the centreline velocity.
is there any utility that can do that for me or I have to write a code?
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Old   December 11, 2010, 04:50
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Quote:
Originally Posted by yashar.afarin View Post
Hi Su,

thank you very much for your response.
indeed, I want to compute my jet width along the jet centreline. for that reason, I have to determine the centreline velocity(u(x,0,0)) that is function of x-axis then compute distance from jet centreline in y-direction where the x component of velocity become half of the centreline velocity.
is there any utility that can do that for me or I have to write a code?
A possible way can be described as follows:
1) Cut several planes along centreline transversely.
2) select points on these planes. These points are not necessary on the cell center.
3) interpolate values to the selected points
4) find the point who has maximum velocity on each plane, and this point is on the cenerline
5) loop all the planes. In each planes, fix Y, and change z from min to maximum, and find the two points who has the most approaching value to half the maximum velocity. Distance between these two points is the jet width on this line. In 3D the wide should be different for different Y.

The points you selected shoud cover your jets. The algorithm is an approximated method.

If you have problem in implementation, please let me know.

Regards, Junwei
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Old   December 11, 2010, 10:40
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Quote:
Originally Posted by su_junwei View Post
A possible way can be described as follows:
1) Cut several planes along centreline transversely.
2) select points on these planes. These points are not necessary on the cell center.
3) interpolate values to the selected points
4) find the point who has maximum velocity on each plane, and this point is on the cenerline
5) loop all the planes. In each planes, fix Y, and change z from min to maximum, and find the two points who has the most approaching value to half the maximum velocity. Distance between these two points is the jet width on this line. In 3D the wide should be different for different Y.
Hi Su

I really appreciate all the help you gave me.
basically, I think that it would better for me to export my result to a .dat file and write a separate(from OF) code to digest in my data but I would appreciate if you could answer my question:
how I could export my data so that I could specify and link for each point(cell centre) , the position(x,y,z) and velocity(u,v,w) variables of that point as a same file?


Best regards,
Yashar
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