[ocin199]

Hi All,

I'm pretty new to Paraview/Openfoam and I currently need a little bit of help.

What I want to show:
-Velocity Profiles like in the picture below
-Only lines and no arrows (arrows would be to confusing)
-The profiles should be created for example every 0.1 meter
-The relative velocity (U/U0) (I already solved this problem)

I tried it with PlotOverLine and Glyph, but the result was not what i expected.

I hope someone can help me with that.

Thanks a lot in advance.

[piu58]

May be am an not a paraFoam expert enough, but I assume this is a task too hard for that program. I recommend gnuplot.

In the first step the data for each profile has to be stored in a file. Therfore you may use the sample utility. You need to write a sampleDict which contains the lines along which you wish to extract the data. This is easy in your case. The sample Dict should look similar to this:

sets (
    w0 {  type uniform; axis distance; nPoints 500;
	start (-0.5 0 0); 
	end   (-1 0 0);
    }
    w10 {  type uniform; axis distance; nPoints 300;
	start (-0.492404 0.0868241 0); 
	end   (-0.689365 0.121554 0);
    }
	: (more samples)
}
	
);

Your lines need to be different of course. You get files with the names you gave in the postProcessing-sets-yourTimestep directory.

Maybe you have to calculate some things before printing, for instance the total value of the velocity from the components. This can be done with awk in the form:

cat myfile | awk '// {print $1, sqrt($2*$2+$3*$3+$4'*$4)}' > anotherFile

$1 is the first "word" in each line, $2 the second one and so on.

In your case you need at least to shift the U data along the axis and scale the velocity range so it fits to the diagram.

Eventual you may prepare a gnuplot file which prints these data. This may look like

set yrange [0:5] 
set xrange [0:190] 
set xlabel "U, m/s"
set ylabel "l, cm" 
plot "firstfile title "" with lines 1,"secondfile" title "" with lines 1,.....
pause -1

This gives the velocity "shells" form your example, not the lines/ arrows. This looks not bad and is similar to the graphs in textbooks. I found it helpful to add U=0-Achse (simple lines) and a measure vor the U velocity. This ma be done with prepared lines (files).

I made s script file for the flow around a sphere which gives a result similar to yours. I append a graphic of that.

[ocin199]

Thank you very very much!
This is exactly what i was looking for!