OpenFOAM/C2/Creating-simple-geometry-in-OpenFOAM/English
Title of script: Creating simple geometry in OpenFOAM
Author: Rahul Ashok Joshi
Keywords: Video Tutorial,Computational Fluid Dynamics (CFD),OpenFOAM geometry
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Slide 1
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Hello and welcome to the spoken tutorial on creating a simple geometry in OpenFOAM |
Slide 2: Learning Objective | In this tutorial I will show you
How to create a simple geometry How to view geometry in paraview
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Slide 3: System Requirement | To record this tutorial
I am using Linux Operating system Ubuntu 10.04 OpenFOAM version 2.1.0 ParaView version 3.12.0
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Slide 4: System Requirement | The tutorials were recorded using the versions specified in previous slide
Subsequently the tutorials were edited to latest versions To install latest system requirements go to Installation Sheet
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Only narration
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In CFD the Pre-processing part consists of creating geometry and meshing it.
Let us take the Lid driven cavity case as an example. I have already opened the command terminal and entered the path for lid driven cavity
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Slide 5: For OpenFOAM v 5.0 | To source the OpenFOAM version 5, type:
$of5 To go to the run folder, type: $cd $FOAM_RUN To open the cavity case directory, type: $cd tutorials/incompressible/icoFoam/cavity/cavity To list the contents of case directory, type: $ls
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In the command terminal
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There are three folders 0,constant,and system
Geometry is inside the polymesh folder of constant |
Terminal window: type cd constant | In the command terminal type cd constant and press enter |
Type ls | Type ls and press enter
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Type cd polyMesh | type cd polymesh and press enter |
Type ls | type ls and press enter
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Open the blockMeshDict file
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Open the blockMeshDict file with any editor of your choice
In the terminal type gedit blockMeshDict and press enter Minimise the blockMeshDict file |
Slides | Let me switch back to the slides |
Hover over the diagram | In openfoam the entire geometry is broken into blocks |
Block vertex starts from 0 | The blocks are numbered starting from 0 as shown in the figure |
For 2D geometry enter a unit thickness cell in z axis | Note that in OpenFOAM for creating a 2D geometry
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Dimension of Cavity | Lid driven cavity is of length 1 and height 1
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Create empty file
right click >create document>empty file |
On your desktop create an empty file by
(Note that M and D here are capital) |
Copy data from old blockMeshDict file
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Copy the data from the original lid driven cavity blockMeshDict file
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In the blockMeshDict file
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In the file type vertices and press enter |
Insert ( | Put the open brackets and in the next line |
Start with point 0
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Start with 0 point, in brackets enter
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Point 2 in the x-y plane | move towards point 2 in positive x-y plane and enter (1 space 1 space 0) and press enter |
Point 3 in y direction | enter the 3 point in positive y axis
(0 space 1 space 0 ) and press enter |
Point 4 in the front face
enter (1 0 1) |
enter 4 point (1 space 0 space 1) on the front face and press enter |
Points 5,6,7 with unit cell thickness in z axis | Similarly enter the other points with one unit value in the positive z -axis
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Inert ) and ; | close the bracket and insert a semicolon after it |
Type blocks and insert (
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Below vertices are the blocks Insert a Open bracket and press enter
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Enter the vertices of block
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Enter the points for the blocks in a clockwise sense
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Enter grid points in x, y and z axis | After this enter the grid points in the x,y,and z directions |
Enter the mesh/grid size
enter ( 30 30 1) |
In brackets enter (30 space 30 space 1) ,you can modify the grid when needed |
Grid point in z axis is kept as 1 | Grid point in z-axis can be kept as one |
Enter simpleGrading value ( 1 1 1 )
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Leave a space and in brackets enter the simple grading for the mesh (1 space 1 space 1)
Close the bracket and insert a semicolon and press enter
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Type edges | Now type edges,as this is a simple geometry edges can be kept empty |
Insert ( ); | Insert open and closed bracket ,put a semicolon and press enter |
Boundary conditions | Below edges are the boundary conditions. |
Here you need to enter the boundary name for the faces | |
Type boundary
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Type boundary and in the next line and press enter
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Slide : Geometry | In the geometry the upper wall is moving and other three walls are fixed. |
Front and back faces are kept as empty | The front and back faces are termed as empty as this is a 2D problem |
Open the current blockMeshDict file | Open the New blockMeshDict file again |
Boundary patch as moving wall | In boundary put the name of the patch as moving wall |
Insert { | Insert a open curly bracket |
Type of moving wall : wall
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Enter type for the moving wall as wall and
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Let me switch to slides | |
Slide : Geometry | Note that order the points in such a way that the thumb should be normal to that face |
Clockwise curl of fingers | And fingers make a clockwise curl as shown in the figure |
Points should be entered matching the points inserted in vertices | Also note that the points should match with the points inserted in vertices |
Enter (3 7 6 2)
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Enter the face points as (3 space 7 space 6 space 2) as shown in the figure
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Boundary patches for fixedWalls | Similarly enter boundary condition and faces for the fixed wall |
For front and back face enter type as empty | Being a 2D problem the type of boundary
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Insert | Insert open-closed brackets and put a semicolon. |
BlockMeshDict file is completed
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We are done with creating the blockMeshDict file.
The complete blockMeshDict file is as shown here. |
Close the original blockMeshDict file
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Close the original blockMeshDict file
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Type cd .. twice | type cd (dot) (dot) twice to return to the cavity folder Mesh the geometry |
Meshing, type blockMesh | in terminal type: blockMesh and press enter |
Viewing the geometry type paraFoam | View the geometry by typing in the command terminal paraFoam and press enter
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In the object inspector menu click Apply | On the left hand side click Apply on object inspector menu |
Slide | In this tutorial we learnt:
Creating a simple geometry in OpenFOAM Viewed the geometry in Paraview This brings us to the end of the tutorial |
Slide : Assignment | Assignment
Change the geometry parameters : Enter the grid points as (40 40 1) and (50 50 1). View the geometry in paraview
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Slide : About spoken tutorials | Watch the video available at this URL: http://spoken-tutorial.org/What_is_a_Spoken_Tutorial
If you do not have good bandwidth, you can download and watch it. |
Slide : about spoken tutorials | The Spoken Tutorial Project Team
-Conducts workshops using spoken tutorials -Gives certificates to those who pass an online test -For more details, please write to us at contact@spoken-tutorial.org |
Slide: Acknowledgement | Spoken Tutorials are part of Talk to a Teacher project,
It is supported by the National Mission on Education through ICT, MHRD, Government of India. More information on the same is available at the following URL link http://spoken-tutorial.org/NMEICT-Intro |
About the contributor | This is Rahul Joshi from IIT BOMBAY signing off.
Thanks for joining.
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