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,
00:16	I am using: Linux Operating system Ubuntu version 10.04 OpenFOAM version 2.1.0 ParaView version 3.12.0
00:27	In CFD the Pre-processing part consists of creating geometry and meshing it.
00:33	Let us take the Lid driven cavity case of the previous tutorial as an example.
00:38	Recall the path for the earlier tutorial.
00:40	I have already opened the command terminal and entered the path for lid driven cavity.
00:48	There are three folders '0, constant' and 'system'. 'Geometry' is inside the 'polymesh' folder of 'constant'.
00:55	In the command terminal, type: cd space constant and press Enter.
01:03	Now, type "ls" and press Enter.
01:06	In this, there is another folder called as 'polyMesh'.
01:10	Now type: cd space polymesh and press Enter.
01:18	Now type "ls" and press Enter.
01:22	This contains the 'geometry' file called as 'blockMeshDict'.
01:26	Open the 'blockMeshDict' file with any editor of your choice.
01:30	In the terminal, type: gedit space blockMeshDict( Note that M and D are capital) and press Enter.
01:45	Let me drag this to the capture area.
01:49	Now minimize this.
01:53	Let me switch back to the slide.
01:55	In openfoam, the entire geometry is broken into blocks .
01:59	The blocks are numbered starting from 0 (zero) as shown in the figure.
02:08	Note that in OpenFOAM, for creating a 2D geometry you need to give an unit cell thickness value in the z-axis.
02:19	lid driven cavity is of length 1 and height 1. Minimize the slide.
02:29	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).
02:48	Open this. Now, copy the data from the original lid driven cavity 'blockMeshDict' file to the new 'blockMeshDict' file from line 0.
02:59	Scroll up line 0 upto 'convertTometers'. Copy this and paste it here.
03:15	Scroll down. Now leave some space after 'converttometers'.
03:21	Enter 1 as the geometry is in meters. Insert a semicolon and press Enter.
03:30	Again press Enter. In the file, type "vertices" and press Enter.
03:39	Insert the open bracket and press Enter.
03:43	Press the tab key. Start with point 0, insert open, close brackets, Enter.
03:52	0 space 0 space 0 and press Enter. Again, press tab key, open close bracket .
04:02	Move towards point 1 in positive x-axis and enter 1 space 0 space 0 and press Enter.
04:12	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.
04:26	Again press tab key, open close bracket. Enter the 3rd point in positive y-axis 0 space 1 space 0 , press Enter.
04:39	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.
04:51	Similarly, enter the other points with one unit value in the positive z- axis.
04:56	close the bracket and insert a semicolon after it. Press Enter, again press Enter.
05:03	Below vertices are the blocks. Type blocks and press Enter. Insert a open bracket and press Enter.
05:16	Let me switch back to the slides.
05:19	Note that Lid driven cavity is taken as a single block.
05:24	Let me switch back to 'blockmeshdict'.
05:27	Enter the points for the block in the clockwise sense.
05:31	We are using here hexa hedral blocks for meshing.
05:34	Now, type "hex". Leave some space. In brackets, enter 0 space 1 2 3 4 5 6 7 , again leave some space.
05:53	Note that for multiple blocks, the points will be more.
05:58	After this, enter the grid points in the x, y and z directions.
06:02	In brackets, open close brackets, enter 30 space 30 space 1. Leave some space, you can modify the grid as and when needed.
06:16	Grid point in the z-axis can be taken as one.
06:22	Now, leave some space and type "simple Grading". Leave some space, open close bracket, enter 1 space 1 space 1 .
06:36	This is the grid spacing in the x, y and z directions. Press Enter.
06:43	Insert close bracket, insert a semicolon and press Enter.
06:48	Again press Enter. Now type "edges" and press Enter.
06:55	As this is a simple geometry, edges can be kept empty.
07:00	Insert open bracket, press Enter, close the bracket. Insert a semicolon and press Enter.
07:07	Again press Enter. Below edges are the boundary conditions.
07:11	Here you need to enter the boundary names for the faces.
07:15	Type "boundary" and press Enter .
07:19	Insert an open bracket and press Enter.
07:23	Now, let me switch back to the slides.
07:26	In the geometry, the upper wall is moving and other three walls are fixed.
07:31	The front and back faces are named as 'empty' as this is a 2D problem.
07:39	Open the new 'blockMeshDict' file again.
07:42	In boundary, put the name of the patch as 'moving wall' . Press Enter.
07:51	Now, insert a open curly bracket and press Enter.
07:56	Now, enter the type for the moving wall , enter "type" space "wall".
08:06	Insert a semicolon and press Enter.
08:09	Now, insert open bracket and press Enter. Press the tab key, open close bracket.
08:20	In this bracket, enter the points for faces.
08:24	Let me switch back to the slide.
08:27	Note that the order of the points should be in such a way that the thumb should be normal to the face
08:34	and fingers making a curl as shown in the figure.
08:39	The curl can be clockwise or anti-clockwise.
08:43	Also note that the points should match with the points inserted in vertices.
08:48	Now, let me switch back to the new 'blockMeshDict' file.
08:52	Now in the faces, enter 3 space 7 space 6 space 2.
09:01	Let me switch back to the slide. These are the points for the moving wall 3, 7, 6, 2.
09:09	Minimize this. Note that you can start from any point on that face. Now press Enter.
09:17	Close the bracket. Again press Enter. Close the curly bracket.
09:22	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.
09:35	Now, similarly enter boundary condition and faces for the fixed walls.
09:40	Being a 2D problem the type of boundary for the front and back faces can be kept as empty.
09:46	Refer to the figure in the slide. For entering the points, minimize this.
09:52	Insert the closed brackets, put a semicolon and press Enter, again press Enter.
09:59	Now type "mergePatchPairs" and press Enter.
10:04	Since there are no patches to be merged, it can be kept empty.
10:08	Insert open close brackets. Insert a semicolon and press Enter.
10:14	We are done with creating the 'blockMeshDict' file. Save this.
10:18	The complete 'blockMeshDict' file is as shown here.
10:26	Close both the 'blockMeshDict' files.
10:29	Note that the command terminal will not work until the blockMeshDict file is closed.
10:35	Switch back to the terminal. Now, type cd space (dot) (dot) twice to return back to the 'cavity' folder. Now Mesh the geometry.
10:45	To do this, on the terminal, type: "blockMesh" and press Enter.
10:53	Now, view the geometry by typing on the command terminal paraFoam and press Enter.
10:59	This will open the ParaView window.
11:03	Now, on the left hand side, click Apply on object inspector menu. Thus, you can see the geometry.
11:13	Now, let me switch back to the slides.
11:16	In this tutorial, we learnt:
11:18	Creating a simple geometry in OpenFOAM
11:22	Viewing the geometry in Paraview .
11:25	This brings us to the end of the tutorial.
11:29	As an Assignment-
11:31	Change the dimensions of the lid driven cavity, change the grid size to 50 50 1 and view the geometry in paraView.
11:41	Watch the video available at this URL: [1]
11:44	It summarizes the Spoken Tutorial project.
11:46	If you do not have a good bandwidth, you can download and watch it.
11:51	The Spoken Tutorial project team:
11:53	Conducts workshops using spoken tutorials
11:55	Gives certificates to those who pass an online test.
11:59	For more details, please write to: contact@spoken-tutorial.org
12:05	Spoken Tutorial project is part of the Talk to a Teacher project.
12:09	It is supported by the National Mission on Education through ICT, MHRD, Government of India.
12:15	More information on this mission is available at the following URL: [2]
12:19	This is Rahul Joshi from IIT Bombay, signing off. Thanks for joining.

Contributors and Content Editors

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