OpenFOAM/C2/Creating-simple-geometry-in-OpenFOAM/English-timed

Time	Narration
00:01	Hello and welcome to the spoken tutorial on creating simple geometry in OpenFOAM.
00:06	In this tutorial, I will show you:
00:08	How to create simple geometry
00:11	How to view the geometry in paraview.
00:15	To record this tutorial,I am using: Linux Operating system Ubuntu version 10.04 OpenFOAM version 2.1.0 ParaView version 3.12.0
00:26	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.
00:30	In CFD the Pre-processing part consists of creating geometry and meshing it.
00:37	Let us take the Lid driven cavity case of the previous tutorial as an example.
00:41	Recall the path for the earlier tutorial.
00:44	I have already opened the command terminal and entered the path for lid driven cavity.
00:48	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:$ls.
00:54	There are three folders '0, constant' and 'system'. 'Geometry' is inside the 'polymesh' folder of 'constant'.
01:11	In the command terminal, type: cd space constant and press Enter.
01:19	Now, type "ls" and press Enter.
01:21	In this, there is another folder called as 'polyMesh'.
01:26	Now type: cd space polymesh and press Enter.
01:34	Now type "ls" and press Enter.
01:39	To list the contents of the cavity directory, type:$ls. 0 constant system. To open the system directory, type:$cd system. To list the contents of the system directory, type:$ls blockMeshDict controlDict fvSchemes fvSolution.
01:45	This contains the 'geometry' file called as 'blockMeshDict'.
01:48	Open the 'blockMeshDict' file with any editor of your choice.
01:52	In the terminal, type: gedit space blockMeshDict( Note that M and D are capital) and press Enter.
02:07	Let me drag this to the capture area.
02:11	Now minimize this.
02:15	Let me switch back to the slide.
02:17	In openfoam, the entire geometry is broken into blocks .
02:21	The blocks are numbered starting from 0 (zero) as shown in the figure.
02:30	Note that in OpenFOAM, for creating a 2D geometry you need to give an unit cell thickness value in the z-axis.
02:41	lid driven cavity is of length 1 and height 1. Minimize the slide.
02:51	On your desktop, create an empty file by right click > create document > Empty file. Name this as 'blockMeshDict'. (Note that M and D here are capital).
03:10	Open this. Now, copy the data from the original lid driven cavity 'blockMeshDict' file to the new 'blockMeshDict' file from line 0.
03:21	Scroll up line 0 upto 'convertTometers'. Copy this and paste it here.
03:38	Scroll down. Now leave some space after 'converttometers'.
03:44	Enter 1 as the geometry is in meters. Insert a semicolon and press Enter.
03:52	Again press Enter. In the file, type "vertices" and press Enter.
04:01	Insert the open bracket and press Enter.
04:04	Press the tab key. Start with point 0, insert open, close brackets, Enter.
04:14	0 space 0 space 0 and press Enter. Again, press tab key, open close bracket .
04:24	Move towards point 1 in positive x-axis and enter 1 space 0 space 0 and press Enter.
04:34	Again press the tab key, open close bracket. Move towards point 2 in the positive x-y plane and enter 1 space 1 space 0 and press Enter.
04:48	Again press tab key, open close bracket. Enter the 3rd point in positive y-axis 0 space 1 space 0 , press Enter.
05:01	Again press the tab key. Enter the 4th point on the front face, open close bracket, 0 space 0 space 0.1 and press Enter.
05:13	Similarly, enter the other points with one unit value in the positive z- axis.
05:19	close the bracket and insert a semicolon after it. Press Enter, again press Enter.
05:26	Below vertices are the blocks. Type blocks and press Enter. Insert a open bracket and press Enter.
05:39	Let me switch back to the slides.
05:41	Note that Lid driven cavity is taken as a single block.
05:46	Let me switch back to 'blockmeshdict'.
05:48	Enter the points for the block in the clockwise sense.
05:53	We are using here hexa hedral blocks for meshing.
05:56	Now, type "hex". Leave some space. In brackets, enter 0 space 1 2 3 4 5 6 7 , again leave some space.
06:15	Note that for multiple blocks, the points will be more.
06:20	After this, enter the grid points in the x, y and z directions.
06:25	In brackets, open close brackets, enter 30 space 30 space 1. Leave some space, you can modify the grid as and when needed.
06:38	Grid point in the z-axis can be taken as one.
06:44	Now, leave some space and type "simple Grading". Leave some space, open close bracket, enter 1 space 1 space 1 .
06:58	This is the grid spacing in the x, y and z directions. Press Enter.
07:05	Insert close bracket, insert a semicolon and press Enter.
07:11	Again press Enter. Now type "edges" and press Enter.
07:17	As this is a simple geometry, edges can be kept empty.
07:21	Insert open bracket, press Enter, close the bracket. Insert a semicolon and press Enter.
07:28	Again press Enter. Below edges are the boundary conditions.
07:33	Here you need to enter the boundary names for the faces.
07:37	Type "boundary" and press Enter .
07:41	Insert an open bracket and press Enter.
07:45	Now, let me switch back to the slides.
07:48	In the geometry, the upper wall is moving and other three walls are fixed.
07:53	The front and back faces are named as 'empty' as this is a 2D problem.
08:01	Open the new 'blockMeshDict' file again.
08:04	In boundary, put the name of the patch as 'moving wall' . Press Enter.
08:16	Now, insert a open curly bracket and press Enter.
08:20	Now, enter the type for the moving wall , enter "type" space "wall".
08:28	Insert a semicolon and press Enter.
08:33	Now, faces, now press Enter, insert open bracket and press Enter. Press the tab key, open close bracket.
08:47	In this bracket, enter the points for faces.
08:51	Let me switch back to the slide.
08:54	Note that the order of the points should be in such a way that the thumb should be normal to the face
09:01	and fingers making a curl as shown in the figure.
09:06	The curl can be clockwise or anti-clockwise.
09:09	Also note that the points should match with the points inserted in vertices.
09:14	Now, let me switch back to the new 'blockMeshDict' file.
09:18	Now in the faces, enter 3 space 7 space 6 space 2.
09:28	Let me switch back to the slide. These are the points for the moving wall 3, 7, 6, 2.
09:35	Minimize this. Note that you can start from any point on that face. Now press Enter.
09:44	Close the bracket. Again press Enter. Close the curly bracket.
09:55	Another note: we need to enter a semi colon after you insert the points for faces. Now after the curly brackets, press Enter, again press Enter.
10:01	Now, similarly enter boundary condition and faces for the fixed walls.
10:06	Being a 2D problem the type of boundary for the front and back faces can be kept as empty.
10:13	Refer to the figure in the slide. For entering the points, minimize this.
10:19	Insert the closed brackets, put a semicolon and press Enter, again press Enter.
10:26	Now type "mergePatchPairs" and press Enter.
10:32	Since there are no patches to be merged, it can be kept empty.
10:35	Insert open close brackets. Insert a semicolon and press Enter.
10:41	We are done with creating the 'blockMeshDict' file. Save this.
10:46	The complete 'blockMeshDict' file is as shown here.
10:54	Close both the 'blockMeshDict' files.
10:56	Note that the command terminal will not work until the blockMeshDict file is closed.
11:01	Switch back to the terminal. Now, type cd space (dot) (dot) twice to return back to the 'cavity' folder. Now Mesh the geometry.
11:12	To do this, on the terminal, type: "blockMesh" and press Enter.
11:20	Now, view the geometry by typing on the command terminal paraFoam and press Enter.
11:27	This will open the ParaView window.
11:30	Now, on the left hand side, click Apply on object inspector menu. Thus, you can see the geometry.
11:39	Now, let me switch back to the slides.
11:43	In this tutorial, we learnt:
11:45	Creating a simple geometry in OpenFOAM
11:49	Viewing the geometry in Paraview .
11:52	This brings us to the end of the tutorial.
11:56	As an Assignment-
11:58	Change the dimensions of the lid driven cavity, change the grid size to 50 50 1 and view the geometry in paraView.
12:08	Watch the video available at this URL: [1]
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13:02	This is Rahul Joshi from IIT Bombay, signing off. Thanks for joining.

Contributors and Content Editors

DeepaVedartham, Gaurav, PoojaMoolya, Pratik kamble, Sandhya.np14, Sneha