OpenFOAM/C3/Installing-and-running-Gmsh/English-timed
From Script | Spoken-Tutorial
| Time | Narration |
| 00:01 | Hello and welcome to the spoken tutorial on Installing and running Gmsh. |
| 00:08 | In this tutorial, we will learn how to:
Install and run Gmsh and Create a basic geometry in Gmsh. |
| 00:18 | As a prerequisite, the user should have basic knowledge about mesh. |
| 00:24 | To record this tutorial, I am using:
Ubuntu Linux Operating system version 12.04 and Gmsh version 2.8.5 |
| 00:34 | Let me introduce you to Gmsh. Gmsh is an automatic 3-D finite element mesh generator with built-in pre and post-processing facilities.
It's an open-source software. |
| 00:51 | It is advantageous creating complex geometries in gmsh than blockmesh utility of OpenFOAM like blades, aerofoil.
OpenFOAM supports importing mesh from third party meshing software like Gmsh. |
| 01:08 | Let me show you how to install Gmsh.
Gmsh can be installed using Synaptic Package Manager. |
| 01:15 | Let me open Synaptic Package Manager for you. It will ask for your password. Type in your password. |
| 01:25 | In the search box, type "gmsh" and click on the checkbox in front of gmsh. And, click on Mark for installation. Click on Apply. |
| 01:40 | Again, click Apply. This might take some time. Your Gmsh is now installed. |
| 01:50 | Alternately, you can also download Gmsh from the Gmsh website. Let me open the browser for you. |
| 01:59 | In the address bar, type: http://geuz.org/gmsh/ and press Enter. |
| 02:09 | Scroll down to the Download and select the current stable release according to your operating system. I will select Linux 64-bit. Click on Save file and press OK. |
| 02:26 | After finishing your download, go to the Downloads folder. |
| 02:31 | Here you can see the tar file. Extract this file. A new folder will be created. |
| 02:41 | Open the folder. Go to bin and click on the gmsh icon. |
| 02:49 | You can see the Gmsh start screen. Now we will create a cube using Gmsh. |
| 02:57 | Here you can see the cube with sides equal to one unit. |
| 03:03 | Let me switch back to Gmsh. On the left hand side, you can see the module tree with Geometry, Mesh and Solver. |
| 03:14 | Go to Geometry >> Elementary entities. Click on Add. Click on Point. A new window will appear. |
| 03:25 | Enter the X, Y and Z coordinates starting with (0 0 0) and press Enter. |
| 03:34 | Enter the second coordinate as (1 0 0) and press Enter, third coordinate as (1 1 0) and press Enter, fourth coordinate as (0 1 0) and press Enter. |
| 03:53 | Similarly, add the coordinates for the positive z-direction starting with point (0 0 1) and press Enter. Enter the remaining three coordinates and close the window. |
| 04:10 | I have entered all the eight coordinates. Use the left mouse click to move the points. |
| 04:18 | You can see all the 8 coordinates as points. |
| 04:23 | Now, click on Straight line. It will ask for a start point. Select the first point. |
| 04:33 | It will ask for an end point. Select the end point. |
| 04:37 | A line will be drawn between the two points. Similarly, join all the points. |
| 04:45 | Press 'q' to abort. |
| 04:49 | Now, we will define the faces of the cube. Click on plane surface. It will ask for the surface boundary. |
| 04:59 | Select the edges of the bottom face first. You will notice that the edge we select, turns red in color. |
| 05:08 | It will ask for hole boundaries, if any. Since we do not have any hole in the boundary, press 'e' to end the selection. |
| 05:19 | You will notice that the face will appear with dashed centre lines. Now define the top face. |
| 05:29 | Similarly, define the remaining faces. I have defined all the faces. Press 'q' to abort. |
| 05:39 | Now, we will define the volume of the cube. It will ask for the volume boundary. |
| 05:47 | Select any of the surface boundary and press 'e' to end selection. |
| 05:55 | A yellow dot appears at the centre of the cube which represents the volume. Press q to abort. |
| 06:04 | Now, we will define the physical groups which will be used in exporting the geometry to OpenFOAM. |
| 06:13 | Go to Physical Groups >> Add and click on Surface. |
| 06:19 | Select the front surface first and press e to end the selection. Select the back surface and press e to end the selection. |
| 06:31 | Similarly, select the remaining surfaces. I have selected all the surfaces. Press q to abort. |
| 06:41 | Now, we'll define the physical volume. Click on Volume. It will ask for volume. Click on the yellow dot at the centre of the cube. |
| 06:53 | The yellow dot will turn red in color. Press e to end selection. Press q to abort. |
| 07:02 | Our cube is complete. Let us save our work. |
| 07:07 | Go to File >> Save as. We will name our file as cube.geo. |
| 07:15 | Note that here "geo" stands for geometry. Click Ok. Again click Ok. |
| 07:23 | This brings us to the end of this tutorial. As an assignment, create other simple geometry in Gmsh like cylinder, sphere. |
| 07:35 | In this tutorial We:Learnt to install and run Gmsh using Synaptic Package Manager and website. Created a cube using Gmsh. |
| 07:48 | This video summarizes the Spoken Tutorial project. If you do not have good bandwidth, you can download and watch it. |
| 07:56 | We conduct workshops using spoken tutorials and give certificates. Please contact us at this URL:contact@spoken-tutorial.org
Spoken Tutorial is funded by NMEICT, MHRD, Government of India. |
| 08:11 | The script was created by Gautam Sharma and this is Rahul Joshi from IIT Bombay, signing off. Thanks for joining. |
