View source for OpenFOAM-version-7/C2/Creating-3D-Pipe-Geometry-and-Mesh-in-OpenFOAM/English

'''Title of the script:''' Creating 3D Pipe Geometry and Mesh in OpenFOAM

'''Author:''' Divyesh Variya

'''Keywords:''' OpenFOAM, 3D-Geometry, Pipe, Meshing, ParaView, Pre-Processing, Video-Tutorial, blockMesh



{| border="1" 
|- 
|| '''Visual Cue'''
|| '''Narration'''
|- 
|| Slide: Opening slide
|| Welcome to this tutorial on '''Creating 3D Pipe Geometry and Mesh in OpenFOAM.'''
|- 
|| Slide: Learning Objective
|| In this tutorial, we will learn to:

* Create a '''3D''' geometry using '''blockMeshDict'''
* '''Mesh''' a '''3D''' geometry
* Label the''' boundary patches'''
* Check the '''mesh''' results using''' checkMesh command''' and
* View the '''3D''' geometry and '''mesh '''in''' ParaView'''

|- 
|| 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
* '''gedit Text editor'''

You may use any other '''editor''' of your choice.
|- 
|| Slide: Prerequisites
* If not, please go through the prerequisite '''OpenFOAM '''tutorial on https://spoken-tutorial.org

|| As a prerequisite:
* You should be familiar with creation of a basic geometry using the '''blockMesh''' utility.
* If you are not, please go through the prerequisite '''OpenFOAM '''tutorial on this website.

|- 
|| Slide: Code Files
|| 
* The files used in this tutorial are available in the '''Code Files''' link on this tutorial page 
* Please download and extract them
* Make a copy and then use them while practising

|- 
|| Slide: Hagen Poiseuille flow through a pipe
|| 
* In this tutorial, we will learn to create the geometry for '''Hagen Poiseuille flow through a pipe'''.
* The problem description of '''Hagen Poiseuille flow through a pipe''' is shown in the diagram.

|- 
|| Slide: Pipe Geometry
|| 
* This is the diagram of the geometry for '''Hagen Poiseuille flow through a pipe.'''
* The left and right faces are the '''inlet''' and '''outlet''' respectively.
* The cylindrical face of the geometry is a wall.
* The diameter of the pipe is 1 centimeter and its length is 30 centimeters.

|- 
|| CTRL + ALT + T
|| Open the '''terminal''' by pressing '''Ctrl, Alt''' & '''T''' keys.
|- 
|| [Terminal] Type:

'''cd $FOAM_RUN'''
|| At the '''prompt''', type the following '''command''' to go to the '''RUN directory'''.
|- 
|| Only Narration
|| Here onwards, please remember to press the '''Enter''' key after typing each '''command'''.
|- 
|| [Terminal] Type:

'''cp -r $FOAM_TUTORIALS/incompressible/icoFoam/cavity/cavity pipe'''
|| Let us now copy the '''cavity case''' from the '''icoFoam TUTORIAL directory''' to the '''RUN directory'''.

Type the following '''command''' to do so.
|- 
|| [Terminal] Highlight: '''pipe'''
|| Note that the '''cavity case''' is copied to the '''pipe''' directory.
|- 
|| [Terminal] Type:

'''mv pipe/0 pipe/0.Orig'''
|| In this tutorial we don’t need to define '''initial''' and '''boundary conditions''' in '''0''' time.

Type this '''command''' to rename '''0''' folder to '''0 dot O r i g'''
|- 
|| [Terminal] Type:

'''gedit pipe/system/blockMeshDict'''
|| The '''blockMeshDict''' file is located in the '''system''' folder.

Open this file in a '''text editor'''. I am doing it in the '''gedit text editor'''.
|- 
|| [gedit - '''blockMeshDict''']
|| Now we can see the '''blockMeshDict''' file in the '''text editor.'''
|- 
|| [gedit - '''blockMeshDict'''] Highlight

'''Selection in the Text Editor >> Delete'''
|| Delete the lines from '''convertToMeters''' to the end of the file as shown here.

The remaining content is common for all '''blockMeshDict''' files.
|- 
|| [gedit - '''pipe''']
|| Next, open the '''pipe.txt''' file that you had downloaded in the '''text editor'''.
|- 
|| [gedit - '''blockMeshDict'''] Highlight

'''Selection in the Text Editor >> Copy'''
|| Copy the entire content of the text file.

|- 
|| [gedit - '''blockMeshDict''']
|| Now switch back to the '''blockMeshDict''' file.
|- 
|| [gedit - '''blockMeshDict''']

'''Paste '''
|| And paste the copied contents into the '''blockMeshDict '''file as shown.
|- 
|| [gedit - '''blockMeshDict'''] Highlight 

'''0.01'''
|| Note that all the dimensions will be in '''centimeters'''.
|- 
|| Slide: Vertices Detail
|| 
* Vertices are shown in the slide. 
* Here we are going to use 18 vertices to define the geometry of a '''pipe'''.
* For example, two reference points 0 and 17 are on (0 0 0) and (0 0 30) respectively.

|- 
|| [gedit - '''blockMeshDict'''] Highlight

'''Selection in the Text Editor >> vertices '''
|| All 18 points are defined in the vertices section, in the '''blockMeshDict''' file as shown.
|- 
|| Only Narration
|| Now let me switch back to the '''Slides'''.
|- 
|| Slide: Block Detail
|| 
* Here we will use 5 '''hexahedral blocks''' to define the''' pipe''' geometry.
* As you can see, the '''center hexahedral block''' is separately shown in the figure on the right.
* To define this '''block''', we need to type the back plane’s vertices first.
* The vertices should be ordered anti-clockwise when viewed along the negative '''z-axis'''.
* The front plane’s vertices should also follow the same order.

|- 
|| Slide: Block Detail

Highlight: '''hex (1 2 3 4 9 10 11 12) (8 8 80) simpleGrading (1 1 1)'''
|| An example is shown in the slide.

The same '''block''' can be defined correctly in more than one way.

|- 
|| Slide: Block Detail

Highlight: '''(8 8 80)'''
|| To generate '''3D mesh''' we are using:

* 8 '''cells''' in '''X direction''', 
* 8 '''cells''' in '''Y direction''' and 
* 80 '''cells''' in '''Z direction'''.

|- 
|| [gedit - '''blockMeshDict'''] Highlight

'''Selection in the Text Editor >> blocks'''
|| Other four '''blocks''' are defined in the '''blockMeshDict''' file as shown.

|- 
|| Slide: Geometry Arc Detail
|| For the '''curved''' geometry, we need to define the '''edges'''. 
|- 
|| Slide: Geometry Arc Detail
|| 
* There are a total of 16 '''arcs''' that we need to define.
* The '''arcs''' and the '''intermediate points''' are shown in the slide.
* Note that I have used the '''midpoint''' of the '''arc''' as the '''intermediate point'''.
* However, any other point through which the '''arc''' passes is acceptable.

|- 
|| Slide: Geometry Arc Detail

Highlight: '''arc 5 6 (0 0.5 0)'''
|| For example, the''' edge''' from point number '''5''' to '''6''' is passing through (0 0.5 0).
|- 
|| [gedit - '''blockMeshDict'''] Highlight

'''Selection in the Text Editor >> edges'''
|| All 16 '''arcs''' are defined in the '''edges''' section in the '''blockMeshDict''' file as shown.
|- 
|| [gedit - '''blockMeshDict'''] Highlight 

'''arc 5 6 (0 0.5 0)'''
|| The '''curved edge''' connecting points 5 and 6 is defined as shown.

|- 
|| [gedit - '''blockMeshDict'''] Highlight 

'''arc'''
|| The '''edge''' is an '''arc'''.

|- 
|| [gedit - '''blockMeshDict'''] Highlight 

'''5 6'''
|| Its two end points''' are 5 and 6.

|- 
|| [gedit - '''blockMeshDict'''] Highlight 

'''(0 0.5 0)'''
|| The '''coordinates''' of the point through which the '''arc''' passes through is 0, 0.5, 0

|- 
|| Only Narration
|| Let’s label the '''boundary patches'''.

The '''boundary''' faces should be labelled appropriately.

The labels are used to impose '''boundary conditions''' on the respective faces.
|- 
|| [gedit - '''blockMeshDict'''] Highlight 

'''Selection in the Text Editor >> inlet'''
|| The '''inlet boundary''' is defined as shown.

|- 
|| [gedit - '''blockMeshDict'''] Highlight 

'''Selection in the Text Editor >>'''
|| The''' inlet boundary''' has 5 faces.

These faces are defined as shown.
|- 
|| [gedit - '''blockMeshDict'''] Highlight 

'''Selection in the Text Editor >> outlet and wall'''
|| The '''outlet '''and''' wall boundary''' is defined as shown.

|- 
|| Only Narration
|| Note that all '''boundaries''' have more than one face.
|- 
|| [gedit - '''blockMeshDict'''] Highlight 

'''Selection in the Text Editor >> mergePatchPairs'''
|| We do not have any '''patches '''or  internal faces to merge.

Therefore, we leave the '''mergePatchPairs''' field empty.
|- 
|| CTRL+S >> Close Text Editor
|| Now, save the '''blockMeshDict '''file and close the '''text editor'''.
|- 
|| [Terminal] Type:

'''cd pipe'''
|| Now, go to the '''terminal''' and navigate to the '''pipe directory'''.
|- 
|| [Terminal] Type:

'''blockMesh'''
|| Type '''blockMesh command''' and press '''Enter'''. 

|- 
|| [Terminal] Highlight

'''End'''
|| The '''meshing''' is now complete.

|- 
|| [Terminal] Highlight

'''Patches section'''
|| As we can see in '''terminal''' results, three '''patches''' are created.

|- 
|| [Terminal] Type:

'''checkMesh'''
|| Now, let’s check '''mesh''' results and quality.

To do that type '''checkMesh''' in the '''terminal''' and press '''Enter'''.

Note that '''M '''in''' checkMesh''' is capital.
|- 
|| Only Narration
|| We get the results printed of the '''mesh''' we created.
|- 
|| [Terminal] Highlight

'''Max skewness = 0.6954 OK.'''

'''Non-orthogonality check OK.'''

'''Max aspect ratio = 30.3404 OK.'''




'''Overall domain bounding box '''
|| Here we can see:

* '''Skewness'''

* '''Orthogonality'''

* '''Aspect ratio'''

* '''Negative volume''' values if they are present

In our case, no negative volume is present.

* '''Bounding box coordinates''' and

|- 
|| [Terminal] Highlight

'''Overall number of cells of each type:'''

'''hexahedra: 25600'''

'''prisms: 0'''

'''wedges: 0'''

'''pyramids: 0'''

'''tet wedges:0'''

'''tetrahedra:0'''

'''polyhedra: 0'''
|| 
* Number of '''cells''' with their '''types'''.

|- 
|| [Terminal] Type '''paraFoam'''

|| To view '''mesh''' in '''paraview''' type '''paraFoam''' and press '''Enter'''.
|- 
|| [ParaView] Click 

'''Apply'''
|| Click on '''Apply''' on the left side of your window in the '''Properties''' tab.

Now you can see '''pipe''' geometry in the''' Layout window'''.
|- 
|| [ParaView] '''Rotate geometry'''
|| You can rotate geometry in the '''Layout''' window by pressing the left mouse button and dragging.
|- 
|| [ParaView]

'''Click on Surface >> Click on Surface with Edges'''
|| Click on '''Surface''' available in the '''Active Variable Controls.'''

Then change it to '''Surface with Edges'''.
|- 
|| [ParaView]


'''Click on vtkBlockColors >> SolidColor'''
|| Click on '''vtkBlockColors''' available in the '''Active Variable Controls.''' 

And change it to '''SolidColor'''.

You can now see the '''mesh structure''' of '''pipe''' geometry that we created.
|- 
|| [ParaView] '''Close ParaView'''
|| You can close the '''ParaView''' window.
|- 
|| Only Narration
|| With this we have come to the end of the tutorial.
|- 
|| Slide: Summary
|| To summarize, in this tutorial we have learnt to,

* Create a '''3D''' geometry using '''blockMeshDict'''
* Mesh a '''3D''' geometry
* Label the''' boundary patches'''
* Check the '''mesh''' results using '''checkMesh command''' and
* View the '''3D geometry''' and '''mesh '''in''' ParaView'''

|-
|| 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 in this forum.

|-
|| Slide: FOSSEE Forum
|| 
* Do you have any general/technical questions?
* Please visit the forum given in this 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.
|-
|}