Difference between revisions of "OpenFOAM/C2/Supersonic-flow-over-a-wedge/English-timed"

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| In this tutorial, we learnt: * '''Solving a compressible flow problem'''
 
| In this tutorial, we learnt: * '''Solving a compressible flow problem'''
'''Velocity''' and '''pressure contour''' for the wedge and  
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  '''OpenFOAM utility''' for calculating the '''Mach number'''.
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'''Velocity''' and '''pressure contour''' for the wedge and  '''OpenFOAM utility''' for calculating the '''Mach number'''.
  
 
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| This brings us to the end of the tutorial. Watch the video available at this URL:
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| This brings us to the end of the tutorial. Watch the video available at this URL: http://spoken-tutorial.org/What_is_a_Spoken_Tutorial  
http://spoken-tutorial.org/What_is_a_Spoken_Tutorial  
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| The Spoken Tutorial Project team:
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| The Spoken Tutorial Project team: Conducts workshops using spoken tutorials  
Conducts workshops using spoken tutorials  
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Gives certificates to those who pass an online test.
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Gives certificates to those who pass an online test. For more details, please write to us at '''contact@spoken-tutorial.org'''
For more details, please write to us at '''contact@spoken-tutorial.org'''
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| '''Spoken Tutorials''' project is  part of '''Talk to a Teacher''' project. It is supported by the National Mission on Education through ICT, MHRD, Government of India.
 
| '''Spoken Tutorials''' project is  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:
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http://spoken-tutorial.org/NMEICT-Intro
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More information on the same is available at the following URL link: http://spoken-tutorial.org/NMEICT-Intro
  
 
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Revision as of 10:46, 24 March 2017

Time Narration
00:01 Hello and welcome to the spoken tutorial on Supersonic flow over a wedge using OpenFOAM.
00:07 In this tutorial, I will show you: * How to solve a compressible flow problem of supersonic flow over a wedge How to postprocess the results in paraView.
00:18 To record this tutorial, I am using:Linux Operating system Ubuntu version 10.04OpenFOAM version 2.1.0ParaView version 3.12.0
00:30 To practice this tutorial, a learner should have some basic knowledge of Compressible flows andGas Dynamics.
00:38 Let us now solve supersonic flow over a wedge using OpenFOAM and see the shock structure formed using paraview.
00:47 The problem consists of a wedge with a semi-angle of 15 degrees kept in a uniform supersonic flow.
00:55 The Inlet velocity is 5 meters per second.
01:00 The boundary conditions are set as shown in the figure.
01:05 The type of solver I am using here is rhoCentralFoam.
01:10 It is a Density-based compressible flow solver. It is based on central- upwind schemes of Kurganov and Tadmor.
01:21 Open a command terminal . To do this, press ctrl +alt+ t keys simultaneously on your keyboard.
01:28 In the command terminal, type the path for supersonic flow over a wedge.
01:35 In the terminal, type "run" and press Enter.
01:40 cd space tutorials and press Enter.cd space compressible and press Enter.cd space rhoCentralFoam and press Enter.
02:02 cd space wedge15Ma5
02:13 This is the name of the folder of supersonic flow over the wedge in rhoCentralFoam and press Enter.
02:21 Now, type "ls" and press Enter.
02:24 You will see three folders: 0, constant and system.
02:29 Now, open the blockMeshDict file. To do this,
02:34 type cd space constant and press Enter.
02:41 cd space polyMesh note that 'M' here is capital and press Enter.
02:49 Now type "ls" and press Enter. You can see the blockMeshDict file.
02:54 To view the blockMeshDict file, type gedit space blockMeshDict. Note that 'M' and 'D' here are capital, press Enter.
03:08 Let me drag this to the capture area, scroll down.
03:14 In this, you need to calculate the co-ordinates for the wedge.
03:20 This has been already calculated and set up in the problem.
03:23 The rest of the data remains the same.
03:29 In boundary patches, boundaries are set as shown in the figure.
03:33 Close blockMeshDict file.
03:36 In the command terminal, type cd space ..(dot dot) twice to return back to wedge folder.
03:45 Now open the 0 (zero) folder.
03:51 To do this, type cd space 0 and press Enter.
03:58 Type "ls" and press Enter.
04:02 This contains the initial boundary condition for pressure, velocity and Temperature.
04:10 Type cd space .. (dot dot) and press Enter. Now we need to mesh the geometry.
04:19 To do this, in the command terminal, type "blockMesh" and press Enter. Meshing has been done.
04:32 Now, to view the geometry- in the command terminal, type "paraFoam" and press Enter. This will open the paraview window.
04:45 On the left hand side of object inspector menu, click APPLY.
04:53 In this, you can see the geometry in which the rectangular section upstream changes to a wedge downstream. Close the paraview window.
05:05 Now, run the solver rhoCentralFoam.
05:11 To do this, in the command terminal, type "rhoCentralFoam" and press Enter.
05:20 The iterations running can be seen in the terminal window.
05:24 Iterations running will stop after it converges or at the end of the time steps. Now, the solving has been done.
05:34 To visualize these results, let us open the paraview window once again.
05:40 In the command terminal, type “paraFoam” and press Enter.
05:49 Again on the left hand side of object inspector menu, click APPLY.
05:56 On the left hand side top, in active variable control menu, you will see a drop-down menu showing solid color. Now, click on it and change from solid color to capital 'U'.
06:14 Now, make the color legend ON by clicking on the left hand side top of active variable control menu and make the color legend 'ON'. Click on it.
06:28 On top of the Paraview window, you can see the VCR control. Click on PLAY.
06:37 You can see the final results of U velocity.
06:42 Now, scroll down the properties in object inspector menu on the left hand side. Now click on Display besides Properties.
06:56 Scroll down and click on Rescale to Size. You can see the final value of Velocity, magnitude.
07:05 Similarly, you can select pressure. You can see the final result of pressure. Now, close the paraView window.
07:16 You can also calculate the Mach number for the flow. To do this, we can use the Openfoam utility by typing "Mach" in the command terminal.
07:26 Type Mach.
07:29 Note that 'M' here is capital and press Enter. You can see that Mach number is calculated for each time step.
07:36 Now, again open the paraview window by typing in the command terminal "paraFoam" and press Enter.
07:48 Click APPLY, scroll down. In volume fields, check the 'Ma' box and again click APPLY.
08:04 On top of the active variable control menu, click on Solid Color and change it to 'Ma'.
08:11 In the VCR control menu, again click on PLAY and make the color legend 'ON'.
08:21 You can see the Mach number in the color legend and the corresponding colours.
08:29 We notice here that when the wedge is kept in supersonic flow, it produces a shock across which the flow properties like temprature, pressure

and density drastically change.

08:43 Now, let me switch back to the slides. The solved tutorial can be validated with exact solution available in basic books of Aerodynamics by John D Anderson.
08:55 In this tutorial, we learnt: * Solving a compressible flow problem

Velocity and pressure contour for the wedge and OpenFOAM utility for calculating the Mach number.

09:06 As an Assignment, vary the wedge angle between 10 ° to 15 ° to view the shock characteristic for the flow.
09:14 This brings us to the end of the tutorial. Watch the video available at this URL: http://spoken-tutorial.org/What_is_a_Spoken_Tutorial
09:21 It summarizes the Spoken Tutorial project. If you do not have good bandwidth, you can download and watch it.
09:28 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

09:41 Spoken Tutorials project is 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

09:56 This script has been contributed by Arvind M and this is Rahul Joshi from IIT Bombay, signing off. Thanks for joining.

Contributors and Content Editors

DeepaVedartham, PoojaMoolya, Pratik kamble, Sandhya.np14