OpenFOAM/C2/Supersonic-flow-over-a-wedge/English-timed

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	The tutorials were recorded using the versions specified in previous slide. Subsequently the tutorials were edited to latest versions. To install latest system requirements go to Installation Sheet
00:35	To practice this tutorial, a learner should have some basic knowledge of Compressible flows andGas Dynamics.
00:43	Let us now solve supersonic flow over a wedge using OpenFOAM and see the shock structure formed using paraview.
00:52	The problem consists of a wedge with a semi-angle of 15 degrees kept in a uniform supersonic flow.
01:00	The Inlet velocity is 5 meters per second.
01:05	The boundary conditions are set as shown in the figure.
01:10	The type of solver I am using here is rhoCentralFoam.
01:15	It is a Density-based compressible flow solver. It is based on central- upwind schemes of Kurganov and Tadmor.
01:26	Open a command terminal . To do this, press ctrl +alt+ t keys simultaneously on your keyboard.
01:33	In the command terminal, type the path for supersonic flow over a wedge.
01:40	In the terminal, type "run" and press Enter.
01:45	cd space tutorials and press Enter.cd space compressible and press Enter.cd space rhoCentralFoam and press Enter.
02:07	cd space wedge15Ma5
02:18	This is the name of the folder of supersonic flow over the wedge in rhoCentralFoam and press Enter.
02:26	Now, type "ls" and press Enter.
02:29	You will see three folders: 0, constant and system.
02:34	Now, open the blockMeshDict file. To do this,
02:39	type cd space constant and press Enter.
02:46	cd space polyMesh note that 'M' here is capital and press Enter.
02:54	Now type "ls" and press Enter. You can see the blockMeshDict file.
02:59	To view the blockMeshDict file, type gedit space blockMeshDict. Note that 'M' and 'D' here are capital, press Enter.
03:13	Let me drag this to the capture area, scroll down.
03:19	In this, you need to calculate the co-ordinates for the wedge.
03:25	This has been already calculated and set up in the problem.
03:28	The rest of the data remains the same.
03:34	In boundary patches, boundaries are set as shown in the figure.
03:38	Close blockMeshDict file.
03:41	In the command terminal, type cd space ..(dot dot) twice to return back to wedge folder.
03:50	Now open the 0 (zero) folder.
03:56	To do this, type cd space 0 and press Enter.
04:03	Type "ls" and press Enter.
04:07	This contains the initial boundary condition for pressure, velocity and Temperature.
04:15	Type cd space .. (dot dot) and press Enter. Now we need to mesh the geometry.
04:24	To do this, in the command terminal, type "blockMesh" and press Enter. Meshing has been done.
04:37	Now, to view the geometry- in the command terminal, type "paraFoam" and press Enter. This will open the paraview window.
04:50	On the left hand side of object inspector menu, click APPLY.
04:58	In this, you can see the geometry in which the rectangular section upstream changes to a wedge downstream. Close the paraview window.
05:10	Now, run the solver rhoCentralFoam.
05:16	To do this, in the command terminal, type "rhoCentralFoam" and press Enter.
05:25	The iterations running can be seen in the terminal window.
05:29	Iterations running will stop after it converges or at the end of the time steps. Now, the solving has been done.
05:39	To visualize these results, let us open the paraview window once again.
05:45	In the command terminal, type “paraFoam” and press Enter.
05:54	Again on the left hand side of object inspector menu, click APPLY.
06:01	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'.
06:19	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.
06:33	On top of the Paraview window, you can see the VCR control. Click on PLAY.
06:42	You can see the final results of U velocity.
06:47	Now, scroll down the properties in object inspector menu on the left hand side. Now click on Display besides Properties.
07:01	Scroll down and click on Rescale to Size. You can see the final value of Velocity, magnitude.
07:10	Similarly, you can select pressure. You can see the final result of pressure. Now, close the paraView window.
07:21	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.
07:31	Type Mach.
07:34	Note that 'M' here is capital and press Enter. You can see that Mach number is calculated for each time step.
07:41	Now, again open the paraview window by typing in the command terminal "paraFoam" and press Enter.
07:53	Click APPLY, scroll down. In volume fields, check the 'Ma' box and again click APPLY.
08:09	On top of the active variable control menu, click on Solid Color and change it to 'Ma'.
08:16	In the VCR control menu, again click on PLAY and make the color legend 'ON'.
08:26	You can see the Mach number in the color legend and the corresponding colours.
08:34	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.
08:48	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.
09:00	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.
09:11	As an Assignment, vary the wedge angle between 10 ° to 15 ° to view the shock characteristic for the flow.
09:19	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
09:26	It summarizes the Spoken Tutorial project. If you do not have good bandwidth, you can download and watch it.
09:33	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
10:07	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
10:20	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