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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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 of the previous tutorial as an example. Recall the path for the earlier tutorial, I have already opened the command terminal and entered the path for lid driven cavity
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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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