Difference between revisions of "OpenFOAM/C3/Generating-Mesh-using-snappyHexMesh/English-timed"

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| 10:44
 
| 10:44
 
| Watch the video available at this URL:http://spoken-tutorial.org/What_is_a_Spoken_Tutorial
 
| Watch the video available at this URL:http://spoken-tutorial.org/What_is_a_Spoken_Tutorial
 
 
It summarizes the Spoken Tutorial project. If you do not have good bandwidth, you can download and watch it.
 
It summarizes the Spoken Tutorial project. If you do not have good bandwidth, you can download and watch it.
  

Latest revision as of 15:47, 10 March 2017

Time Narration
00:01 Hello and welcome to the spoken tutorial on generating mesh using snappyHexMesh in OpenFOAM.
00:08 In this tutorial, we will learn to:

Generate mesh using snappyHexMesh utility Simulate temperature distribution of a flange.

00:18 As a pre-requisite, you should know parameters in snappyHexMeshDict to generate mesh.

For more details, refer the tutorial on introduction to snappyHexMesh in OpenFOAM.

00:31 To record this tutorial, I am using:

Ubuntu Linux Operating system version 12.04. OpenFOAM version 2.2.2 ParaView version 3.12.0

00:46 We are solving an existing case of flange fromlaplacianFoam in basic directory.

'laplacianFoam' solver solves simple Laplace equations.

00:58 Now, let us go to home folder and click on OpenFoam-2.2.2 folder.
01:05 You will see tutorials. Click on it.
01:09 Then click on mesh folder.
01:12 You will see the snappyHexMesh folder. Click on it.
01:17 In this folder, create a new folder by name flange_1.
01:24 Now, let's go back two levels.
01:27 Open the basic folder. You will see laplacianFoam folder. Click on it.
01:36 You will see flange case. Click on it to open the folder.
01:42 Copy the three folders 0, constant and system.
01:46 Now, let us go three levels back. Paste the copied folders inside the flange_1 folder.
01:56 Now, let us go one level back. Click on flange folder. You will see constant and system folders.
02:05 Click on system folder.
02:08 Copy snappyHexMeshDict and surfaceFeatureExtractDict from this folder. Now, let us go two levels back.
02:18 Paste these two files inside the system directory of flange_1 folder.
02:27 Now, let us go one level back. Click on constant folder. In this, create a folder by name triSurface.
02:40 Now, let us go four levels back.
02:44 Open the resources folder.
02:48 You will see geometry folder. Now, open the geometry folder.
02:53 In this, you will see flange.stl.gz file. Extract this file.
03:04 Give the path of triSurface folder in constant directory of flange_1 folder. Now close this.
03:16 Open command terminal and enter the path for flange_1 as shown. Type: cd space OpenFOAM-2.2.2/tutorials/mesh/snappyHexMesh/flange_1 and press Enter.
03:42 Now type "ls" and press Enter.
03:46 There are three folders 0, constant and system. Type cd space constant and press Enter.
03:55 Now type "ls" and press Enter. You will see the polymesh and triSurface folders.Type: cd space polymesh and press Enter.
04:09 Now type: "ls" and press Enter. You can see the blockMeshDict file.
04:16 To view the contents of the file, type: gedit space blockMeshDict and press Enter.
04:26 This will open up the blockMeshDict file. This file contains co-ordinates for hex mesh and boundary patches.
04:36 Now close this and in the command terminal, type: cd (space) .. (dot) (dot) and press Enter. Again type: cd (space) .. (dot) (dot) and press Enter.
04:48 Now, type: cd space system and press Enter.
04:53 Now type: "ls" and press Enter. You can see the surfaceFeatureExtractDict file.
05:01 To view the contents of the file, type: gedit space surfaceFeatureExtractDict and press Enter(Note that F, E and D here are capital).
05:15 This will open up the surfaceFeatureExtractDict file.
05:19 This file contains the information about geometry’s feature edges. The included angle is taken as 150.
05:29 Now close this. In command terminal, type: gedit space snappyHexMeshDict and press Enter(Note that H, M and D here are capital).
05:45 This will open up the snappyHexMeshDict file. This file contains all the instructions about snappyHexMesh.
05:53 In snappyHexMeshDict, I have already made some changes. I have named flange.stl same as that of STL file which is in the constant/trisurface directory.
06:11 For Explicit feature edge refinement in castellatedMeshControls, I have given the file name flange.eMesh. This file is obtained by surfaceFeatureExtract utility.
06:23 The remaining details in the snappyHexMesh have changed as per requirements.
06:30 Now close this and in command terminal, type cd (space) .. (dot) (dot) and press Enter.
06:38 Type: cd space 0 (zero) and press Enter.
06:44 Type "ls" and press Enter. You can see the 'T' file.
06:50 Now type: gedit space T and press Enter.
06:55 This will open up the 'T' file. You will see the initial conditions for every patch.
07:04 Now, we have to give initial conditions for all patches of flange.
07:11 Copy the initial conditions for patch 1 and paste it after patch 4, in the same file 'T.' Now type "flange_" before this patch 1.
07:28 Similarly, we can do this for patch 2, 3 and 4. Save this 'T' file and close it.
07:37 And, in the command terminal type: cd (space) .. (dot) (dot)and press Enter.
07:43 Now, we need to mesh the geometry. For that, in command terminal, type: blockMesh and press Enter. Meshing is done.
07:55 Now type: surfaceFeatureExtract and press Enter (Note that F and E here are capital).Surface feature extraction is done.
08:09 Now, type: snappyHexMesh -(dash) overwrite and press Enter. - (dash) overwrite command will prevent copying the files from the last time folders.
08:24 If not, the resulting meshes will be inside the next time folders, possibly the folders 1, 2 and 3.
08:31 Meshing will take some time. Now meshing is completed.
08:36 For simulating temperature distribution, we are using 'laplacianFoam' solver.
08:42 In the command terminal, type: laplacianFoam and press Enter (Note that F here is capital).
08:51 Iterations running will be seen in the terminal window.
08:55 Once solving is completed, type: paraFoam and press Enter to view the geometry and the results. This will open up the Paraview window.
09:07 On the left hand side of Paraview window, click on Apply. The geometry can be seen here.
09:15 Scroll down the properties panel of the Object Inspector menu. Check the box for T in the Volume Fields and click on Apply.
09:25 Now go to the top of Active variable control drop-down menu. Change from solid color to capital 'T', which is the initial condition for the flange.
09:37 Now on the top of the Paraview window, you can see the VCR controls. Click on the Play button. Now, this is the final result for temperature distribution of a flange.
09:58 Toggle on the color legend by clicking on top left of the Active variable control menu.This is the colour legend for temperature T.
10:09 Now, let me get back to the slides.
10:12 This brings us to the end of the tutorial. As an assignment-
10:16 Change some parameters in the snappyHexMeshDict:

Refinement parameters locationInMesh co-ordinates snapControls etc.

10:26 You can also change the temperature in the '0' (zero) folder and view the results in the Paraview.
10:33 In this tutorial, we learnt :

To generate mesh by snappyHexMesh utility in OpenFoam. Simulate temperature distribution of a flange.

10:44 Watch the video available at this URL:http://spoken-tutorial.org/What_is_a_Spoken_Tutorial

It summarizes the Spoken Tutorial project. If you do not have good bandwidth, you can download and watch it.

10:57 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: contact@spoken-tutorial.org

11:14 Spoken Tutorials are part of Talk to a Teacher project. It is supported by National Mission on Education through ICT, MHRD, Government of India.

More information on the same is available at following URL:http://spoken-tutorial.org/NMEICT-Intro

11:29 This is Chaitrali Ghodke from IIT Bombay, signing off. Thanks for joining.

Contributors and Content Editors

PoojaMoolya, Pratik kamble, Sandhya.np14