Difference between revisions of "OpenFOAM/C2/Supersonic-flow-over-a-wedge/English-timed"
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| − | | In this tutorial, I will show you: * How to solve a '''compressible flow''' problem of '''supersonic flow over a wedge ''' | + | | 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'''. |
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Revision as of 15:04, 10 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: |
| 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. |
