OpenFOAM-version-7/C2/Basic-Post-Processing-using-ParaView/English

Title of the script: Basic Post Processing using ParaView

Author: Divyesh Variya

Keywords: OpenFOAM, Hagen Poiseuille, Paraview, Clip, Streamline, Glyph, Plot-over-line, Parabolic profile, Video-Tutorial

Visual Cue	Narration
Slide: Opening Slide	Hello and welcome to this tutorial on Basic Post Processing using ParaView.
Slide: Learning Objective	In this tutorial, we will learn, Some basic visualization techniques in ParaView Export the field data to .csv file Plot a graph in LibreOffice Suite Calc and Save a screenshot of a view
Slide: System Specifications	To record this tutorial, I am using, Ubuntu Linux OS version 18.04 OpenFOAM version 7 ParaView version 5.6.0 and LibreOffice Suite 6.4
Slide: Prerequisites* Please go through these two tutorials on https://spoken-tutorial.org	As a prerequisite learner should practise, On Simulating Hagen Poiseuille Flow through a Pipe from the OpenFOAM tutorials and Tutorial on Using Charts and Graphs from LibreOffice Suite Calc Please go through these two tutorials on this website.
Press Ctrl + Alt + T keys	Open the terminal by pressing the Ctrl, Alt and T keys together.
Only Narration	From now onwards please remember to press the Enter key after typing each command.
[Terminal] Type: cd $FOAM_RUN	At the prompt, type the following command to go to the run directory.
[Terminal] Type: cd pipe	Navigate to the pipe case folder. We have created this in the “Simulating Hagen Poiseuille Flow through Pipe” tutorial.
[Terminal] Type: paraFoam	Type paraFoam in the terminal to open the case file in paraView.
[ParaView] Uncheck >> inlet and outlet	Go to the properties panel. Scroll down and locate the mesh parts section. Uncheck all patches other than internalMesh.
[ParaView] Click on Apply	Click on the Apply button in the Properties panel.
[ParaView] Click on Solid Color >> Click on U	Click on Solid Color available in the Active Variable Controls. From here, we can change the fields that we want to visualize. Select the U field with the dot, not the one with the box.
[ParaView] Click on Last Frame	From VCR Controls, we can change the time steps and run animation using the Play button. Currently we are on 0 time, which is for the initial field. To go to the last time step, click on the Last Frame button.
Show Picture of ICONS	As you can see, some filter icons are shown here.
[ParaView] Click on Stream Tracer filter	To visualize streamline, click on the Stream tracer icon from Common and Data Analysis Filters.
[ParaView] Change seed type to point source	From the Properties panel we can change the seed type. The two seed types available are: High resolution line source and Point Source High resolution Line Source gives streamlines passing through a line. Point Source gives streamlines passing through a sphere. We will select Point Source.
[ParaView] Set number of points to 1000 >> Uncheck Show Sphere checkbox	Set the number of points to 1000 and uncheck the Show Sphere option to hide the sphere.
[ParaView] Click on Apply	Click on the Apply button in the Properties panel. We can see 1000 streamlines passing through 1000 random points within the sphere.
[ParaView] Click on Delete button	This way we can visualize the streamline. Now Delete the Stream Tracer filter by clicking on the Delete button on the Properties panel.
[ParaView] Click on Glyph filter	Click on the Glyph icon from Common and Data Analysis Filters.
[ParaView] Change Orientation U	Change Orientation Array to U from the Properties panel.
[ParaView] Scale array U	Change Scale array to U in the Properties panel.
[ParaView] Click on Apply	Click on the Apply button in the Properties panel.
[ParaView] Hide pipe.OpenFOAM	Hide pipe.OpenFOAM from the pipeline browser by clicking on the eye icon.
[ParaView] Zoom in render layout with left mouse click and drag	We can see Arrows in the direction of the flow.
[ParaView] Delete Glyph filter	Delete the Glyph filter from the Properties panel.
[ParaView] Click on Clip filter	Click on the clip icon from Common and Data Analysis Filters to clip the mesh.
[ParaView] Uncheck Show plane and invert	Uncheck “Show Plane” and “invert” boxes from the Properties panel.
[ParaView] Click on Apply	Click on the Apply button in the Properties panel.
Only Narration	This way we can clip any mesh and visualize internal flow.
[ParaView] Delete Clip filter	Delete the Clip filter from the Properties panel.
[ParaView] Click on Plot Over Line Filter	Click on the “Plot Over Line” filter from Common and Data Analysis Filters.
[ParaView] Click on Y Axis	Click on Y Axis on the Properties panel and click Apply.
[ParaView]Highlight Line Chart view window	A new line chart window opens automatically with P and U_Magnitude graphs.
[ParaView] Scroll properties panel and uncheck p from series parameter	In the Properties panel, scroll down and locate the series parameters section. Uncheck P from that.
[ParaView] Highlight Line Chart view window	We will get a parabolic profile for velocity in the graph.
[ParaView] Click on Line chart view window Press CTRL+S	Click on the Line Chart View window And press Ctrl+S keys to save data.
[Save File:] Select file type as .csv give name - Y-Axis	Select Files of type as .csv and give the file name Y(hyphen)Axis.
[Save File:] Click >> OK	Click on OK. Again click on OK with default settings.
Only Narration	The data is saved in a .csv file. We can open this file in LibreOffice Calc and compare with an analytical solution.
[ParaView] Click on File >> Save Screenshot...	Now go to the File menu in the menu bar and select Save Screenshot.
[ParaView] File name - velocity File type - .png	Give a File Name and select file type. Here I am saving the screenshot as velocity with the .png file type.
[ParaView] Click >> OK	Click on the OK button.
[ParaView] Click >> OK	The Save Screenshot option window pops up. We can change the size, scaling, coloring and other image options here. With the default values in the settings, click on the OK button.
Only Narration	Screenshot of Parabolic curve profile is saved in our case directory.
[ParaView] Click on Z Axis	Go to the Properties panel. Click on Z Axis and then click on the Apply button.
[ParaView] Uncheck U_Magnitude and check p	Then go to the series parameter section in the Properties panel. Uncheck U_Magnitude field and check p field.
[ParaView] Press CTRL+S Select .csv file type Give a name - Z-Axis Press OK Press OK	Save this data to Z-Axis.csv file as explained earlier.
[ParaView] Close ParaView	Close the ParaView window.
Open File explorer	Open the File explorer from the taskbar.
[File explorer] Open >> OpenFOAM	Open the OpenFOAM directory. Here we can see the username directory of our computer.
[File explorer] Open >> “username directory”	Now open your current user directory. In the user directory we can see the “run” directory.
[File explorer] Open >> run	Open the “run” directory. Our saved work is available here in the pipe directory.
[File explorer] Open >> pipe	Now open the pipe directory.
Only Narration	Here we can see all files including screenshot image and .csv files that we have saved.
[File explorer] Right click on >> Z-Axis.csv	Right click on Z-Axis.csv file.
[File explorer] Click on >> Open With Other Application	From the list, click on the “Open With Other Application” option.
[File explorer] Click on >> View All Application	Now click on the “View All Application” button.
[File explorer] Double click on >> LibreOffice Calc	A list of all the applications available in your computer will appear. From this list find “LibreOffice Calc” and double click on it.
[File explorer] Click on >> OK	A “Text Import” window will open on your screen. At the bottom right corner click on the OK button.
Highlight LibreOffice suite calc	Our file is now open in LibreOffice Calc.
[LibreOffice suite calc] Highlight cells	We have velocity U:0 at Point:0 Velocity U:1 at Point:1 and Velocity U:2 at Point:2.
[LibreOffice suite calc] Highlight cells	We have kinematic pressure p, vtkValidPointMask and arc_length also.
[LibreOffice suite calc] Highlight cells	Necessary data to plot the graph is U:2, Point:2 and p.
[LibreOffice suite calc] Show Graphs	For this demonstration I have created a graph on z-axis versus kinematic pressure. And another graph for z-axis versus velocity.
[LibreOffice suite calc] Show Graphs	And the same way I have created a y-axis versus velocity graph with a y-axis.csv file.
Only Narration	Here you can also compare analytical solutions with OpenFoam solutions.
Only Narration	With this we have come to the end of the tutorial. Let us summarize.
Slide: Summary	In this tutorial, we have learnt, Some basic visualization techniques in ParaView Export field data to .csv file Plot graph in LibreOffice suite calc and Save screenshot of a view
Slide: Assignment	As an assignment: Simulate the Hagen Poiseuille flow for the pipe of 0.5 cm diameter with Inlet velocity 0.05 m/s and outlet pressure 0 Pascal and, Plot graphs of velocity and pressure in ParaView and LibreOffice Calc.
Slide: About the Spoken Tutorial Project	The video at the following link summarises the Spoken Tutorial project. Please download and watch it.
Slide: Spoken Tutorial Workshops	We conduct workshops using Spoken Tutorials and give certificates. Please contact us.
Slide: Spoken Tutorial Forum	Please post your timed queries on this website
Slide: FOSSEE Forum	Do you have any general/technical questions? Please visit the forum given in the link.
Slide: FOSSEE Case Study Project	The FOSSEE team coordinates solving feasible CFD problems of reasonable complexity using OpenFOAM. We give honorarium and certificates to those who do this. For more details, please visit these sites.
Slide: Spoken Tutorial	The Spoken Tutorial project is supported by MHRD, Govt. of India. The script for this tutorial is contributed by Divyesh Variya. And this is Swetha Sridhar from IIT Bombay signing off. Thank you for joining.

Contributors and Content Editors

Divyesh7