CFD Online Discussion Forums - probe a line or lines as similar by sample

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probe a line or lines as similar by sample

Hi foamers，

I am wondering is it possible to probe a line (or lines) with setting the start point and end point as similar that in sample.

Any ideas and advice would be highly appreciated!

Zhou Qiang

Hi,
It's convenient to use #include "fliename":
[probes]

Quote:

probes
{
type probes;
functionObjectLibs ("libsampling.so");
enabled true;
outputControl timeStep;
outputInterval 25;

fields
(
U
UPrime
);
/*
probeLocations
(
( 1 0.15 0.5 )
( 3 0.15 0.5 )
( 1 0.65 0.5 )
( 3 0.65 0.5 )
( 1 0.15 1.5 )
( 3 0.15 1.5 )
( 1 0.65 1.5 )
( 3 0.65 1.5 )
);
*/
probeLocations
(
#include "probeLocations"
);
}

Then in "system" folder, create a new file named probeLocations where you can put your points there, any point within the domain is ok. For efficiency, you can use Excel or ultraEdit to generate your points and paste them into the probeLocations file.

Write in probeLocations like this:

Quote:

(1.7 0.086 1.8)
(1.7 0.090 1.8)
(1.7 0.095 1.8)
(1.7 0.100 1.8)
(1.7 0.105 1.8)
(1.7 0.110 1.8)
(1.7 0.120 1.8)
(1.7 0.140 1.8)
(1.7 0.160 1.8)
(1.7 0.180 1.8)
(1.7 0.200 1.8)
(1.7 0.220 1.8)
(1.7 0.240 1.8)
(1.7 0.260 1.8)
(1.7 0.280 1.8)
(1.7 0.300 1.8)
(1.7 0.320 1.8)
(1.7 0.340 1.8)
(1.7 0.360 1.8)

Good luck!

Nick

Hi, Sun.

Thank you for your advice. In fact, I wanna know how we can probe a line as sample a line as shown below.

Quote:

start (0 0 0);
end (0 0 4);
nPoints 100;

But your suggestion is also constructive and convenient.

Hi, Zhou

As far as I know, there is no such function available. If there is any, please let me know!

I think "probe on a line" is less flexible than providing points directly, since the latter can probe at any place you like, while the former can only get limited locations like 4/100*n as mentioned in your probe line. If I wanna probe more densely near the wall, this would fail me.

So in my opinion, providing probe location is the most versatile and straightforward way!

Best regards!

Nick

probe a point using sampleDict

Dear all:

Is it possible to probe a point to obtain pressure values as postprocessing? I have included the following in my sampleDict to probe the pressure, but when I run sample, I do not get any results.

functions
{
probes1
{

type probes;
functionObjectLibs ("libsampling.so");
region region1;
probeLocations
(
(0 0.5 -0.3)
);

fields (p);

}
}

probe at a point

Apparently there is a dictionary called "probesDict". And the code for that is as follows:
/*--------------------------------*- C++ -*----------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: 2.1.1 |
| \\ / A nd | Web: www.OpenFOAM.org |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/
FoamFile
{
version 2.0;
format ascii;
class dictionary;
object probesDict;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

// Fields to be probed. runTime modifiable!
// To run this file, type "probeLocations" in the solver directory

fields
(
p
);

// Locations to be probed. runTime modifiable!
probeLocations
(
(0.0 0.45 -0.3)

);

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

This is a variation of the one available at this URL:

https://github.com/OpenFOAM/OpenFOAM...tem/probesDict

The dict file I have included here was modified from the one in the URL above so that I could probe a sloshingtank2d problem. The problem I have is that OpenFOAM cannot find the probe location (0 0.49 -0.3) during the postprocessing. Apparently as I am using moving mesh, the point is not always there. Does anyone know of a work around?

Thanks.

Quote:

Originally Posted by michael1023 (Post 400017)

Hi, Sun.

Thank you for your advice. In fact, I wanna know how we can probe a line as sample a line as shown below.

But your suggestion is also constructive and convenient.

Sir, I m also trying to get a probe value at every time-step of U,p,UPrime2Mean and R field along a line. How can I use these code to get it in openfoam? Anykind of help is really acceptable.