View source for 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



{| Border="1"
|- 
|| '''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'''<span style="color:#274e13;"> </span>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
|| In 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.
|-
|}