[Rotidpor]

Hello everyone.


I started using gnuplot because it is a convenient tool to plot data. Basically, you just have to type a line or two in a terminal to have your data plotted.
Yet I don't understand the syntax, I found a way to plot my residuals using an openfoam command which extracts the data in my log file and puts it in a single column text file. This way I can tell gnuplot to plot it correctly using simple commands.
This is what I do :


foamLog -n "name of my log file"
gnuplot
plot './Uz_0'


It works well for single column data files created by foamLog. Now my problem is that I want to do the same with probes. Often, my probe files are two columns files, time/iteration versus quantity of interest. But for the velocity, the file is much more complicated with "(" and ")" and four columns.


Is there a simple way to tell gnuplot how to plot a two column file ? Is there an openFoam utility that can convert the velocity probe file into something more manageable like several one column files, as foamLog does for the logfile ?


Thank you all for any input.

[tomf]

Hi,

Not an OpenFOAM utility, but sed would work for this:

sed 's/[()]/ /g' postProcessing/probes/0/U > postProcessing/probes/0/U_noBrackets

Or if you just want to keep the file, you can do replacement inside the file itself as:

sed -i 's/[()]/ /g' postProcessing/probes/0/U

And than plot on the U_noBrackets or new U file.

Regards,
Tom

[Rotidpor]

Thank you for your answer tomf, it was helpful.


For those who will read this, here is the gnuplot syntax to plot a file with multiple columns : https://stackoverflow.com/questions/...-all-on-y-axis


Another thing : I realised that gnuplot can actually handle parenthesis. You don't need to remove them before trying to plot. Looks like it just ignores them, which is practical.

[SHUBHAM9595]

To all the FOAMers...

This is a small attempt to save ur time.....The following script can be be used to monitor as well as export the probes of pressure, velocity and temperature. The script is written for 3 probe points....you might need to edit it accordingly as per the number of probes and fields that u r observing

#! /bin/sh

set terminal pngcairo enhanced font "Century Schoolbook,20.0" size 1500,1100
set output "U1.png"
set grid
set autoscale
set title "Velocity Probe-1"
set ylabel 'magnitude'
set xlabel 'Time'
set style line 1 
plot "< cat postProcessing/probes/0/U | tr -d '()' " using 1:2 lw 3 title '1probeUx' with lines,\
	 "< cat postProcessing/probes/0/U | tr -d '()'" using 1:3 lw 3 title '1probeUy' with lines,\
     "< cat postProcessing/probes/0/U | tr -d '()'" using 1:4 lw 3 title '1probeUz' with lines,
    set terminal x11 0
	set output
	replot
    pause 1

set terminal pngcairo enhanced font "Century Schoolbook,20.0" size 1500,1100
set output "U2.png"
set grid
set autoscale
set title "Velocity Probe-2"
set ylabel 'magnitude'
set xlabel 'Time'
set style line 1 
plot "< cat postProcessing/probes/0/U | tr -d '()' " using 1:5 lw 3 title '2probeUx' with lines,\
	  "< cat postProcessing/probes/0/U | tr -d '()'" using 1:6 lw 3 title '2probeUy' with lines,\
     "< cat postProcessing/probes/0/U | tr -d '()'" using 1:7 lw 3 title '2probeUz' with lines,
    set terminal x11 1
	set output
	replot
    pause 1
    
set terminal pngcairo enhanced font "Century Schoolbook,20.0" size 1500,1100
set output "U3.png"
set grid
set autoscale
set title "Velocity Probe-3"
set ylabel 'magnitude'
set xlabel 'Time'
set style line 1 
plot "< cat postProcessing/probes/0/U | tr -d '()' " using 1:8 lw 3 title '3probeUx' with lines,\
	  "< cat postProcessing/probes/0/U | tr -d '()'" using 1:9 lw 3 title '3probeUy' with lines,\
     "< cat postProcessing/probes/0/U | tr -d '()'" using 1:10 lw 3 title '3probeUz' with lines,
    set terminal x11 2
	set output
	replot
    pause 1
 
set terminal pngcairo enhanced font "Century Schoolbook,20.0" size 1500,1100
set output "pressure_probes.png"
set grid
set autoscale
set title "Pressure Probes"
set ylabel 'magnitude'
set xlabel 'Time'
set style line 1 
plot "< cat postProcessing/probes/0/p | tr -d '()' " using 1:2 lw 3 title 'Pressure probe 1' with lines,\
	 "< cat postProcessing/probes/0/p | tr -d '()'" using 1:3 lw 3 title 'Pressure probe 2' with lines,\
     "< cat postProcessing/probes/0/p | tr -d '()'" using 1:4 lw 3 title 'Pressure probe 3' with lines,
    set terminal x11 3
	set output
	replot
    pause 1
 
set terminal pngcairo enhanced font "Century Schoolbook,20.0" size 1500,1100
set output "Thermal_probes.png"
set grid
set autoscale
set title "Temperature Probes"
set ylabel 'magnitude'
set xlabel 'Time'
set style line 1 
plot "< cat postProcessing/probes/0/T | tr -d '()' " using 1:2 lw 3 title 'Thermal probe 1' with lines,\
	 "< cat postProcessing/probes/0/T | tr -d '()'" using 1:3 lw 3 title 'Thermal probe 2' with lines,\
     "< cat postProcessing/probes/0/T | tr -d '()'" using 1:4 lw 3 title 'Thermal probe 3' with lines,
    set terminal x11 4
	set output
	replot
    pause 60