Difference between revisions of "OpenFOAM/C3/Flow-over-a-flat-plate/English-timed"
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| − | | In this tutorial, I will teach you about: | + | | In this tutorial, I will teach you about: |
| + | * Geometry of the flat plate | ||
* Changing the grid spacing in '''meshing''' | * Changing the grid spacing in '''meshing''' | ||
* Postprocessing results in '''ParaView''' and | * Postprocessing results in '''ParaView''' and | ||
Revision as of 18:05, 28 June 2016
| Time | Narration |
| 00:01 | Hello and welcome to the spoken tutorial on Flow over a flat plate using OpenFOAM. |
| 00:06 | In this tutorial, I will teach you about:
|
| 00:19 | To record this tutorial, I am using:
|
| 00:30 | Flow over flat plate is a fundamental problem in fluid mechanics. |
| 00:35 | We can visualize the growth of the boundary layer. Boundary layer is a very thin region above the body |
| 00:41 | where the velocity is 0.99 times the free stream velocity. |
| 00:46 | This is a diagram of flow over the flat plate. |
| 00:49 | The boundary conditions are given as follows.
You have the Inlet, the Plate, Top – which is the Farfield and Outlet – which is the pressure outlet boundary. |
| 01:00 | The Free stream velocity U = 1 m/s' and we are solving this for Reynolds number (Re) = 100'. |
| 01:08 | Now let us go to the home folder. In the home folder, click on the OpenFoam folder. |
| 01:15 | Then go to the Run directory. You will see Tutorials. Click on it.
Scroll down and then click on Incompressible. Scroll down. |
| 01:27 | You will see the simpleFoam folder. Click on it. This solver suits our case. |
| 01:34 | In this, create a folder by the name flatplate. Right click - Create New Folder - flatplate. |
| 01:44 | Now, let's open the pitzdaily case. |
| 01:47 | Let me zoom this. Copy the three folders - 0, constant and system. Copy this. |
| 01:56 | Now let us go one level back. Paste these three folders inside the flatplate folder. |
| 02:05 | Open the constant folder and then the polyMesh folder. |
| 02:10 | Change the geometry and boundary condition names in the blockMeshDict file. |
| 02:15 | I have already made the changes. Let us open the blockMeshDict file . Scroll down. The geometry is in meters. |
| 02:25 | We have set the dimensions of the flatplate. |
| 02:29 | We can see the simpleGrading. It is kept as (1 3 1) as we need a finer mesh near the plate. |
| 02:35 | Now close this. Go two levels back. |
| 02:41 | Similarly, make changes in the boundary condition names inside the files in the '0' folder. |
| 02:48 | These files have pressure, velocity and wall functions. |
| 02:54 | To calculate the values of wall functions, please refer to the earlier tutorial in the OpenFoam series. Let us go one level back. |
| 03:03 | The system folder can be kept default. Let us close this. |
| 03:09 | Now let us open the terminal window. In the terminal window, type "run" and press Enter. |
| 03:16 | Type cd space tutorials press Enter. |
| 03:21 | Type cd incompressible press Enter. |
| 03:25 | Type cd space simpleFoam press Enter. |
| 03:31 | Now type "ls" and press Enter. |
| 03:34 | We can see the flatplate folder. |
| 03:37 | Now, type cd space flatplate and press Enter. |
| 03:42 | Now type "ls" and press Enter. |
| 03:45 | You can see the three folders 0, constant and system. |
| 03:49 | Now, we will mesh the geometry. We are using a course mesh for this problem. Meshing can be done by typing blockMesh in the terminal. |
| 03:58 | Press Enter. Meshing has been done. |
| 04:01 | Note that if there is some error in the blockMesh file, it will be shown in the terminal window. |
| 04:07 | To view the geometry, type “paraFoam”, press Enter. |
| 04:13 | After the ParaView window opens, on the left hand side of the object inspector menu, click Apply. |
| 04:21 | We can see the geometry. Close the ParaView window. Let me switch back to the slides. |
| 04:28 | The solver we are using here is simpleFoam. SimpleFoam is a steady state solver for in compressible and turbulent flows. |
| 04:37 | Let me switch back to the terminal window. In the terminal window, type "simpleFoam" and press Enter. |
| 04:45 | You will see the iterations running in the terminal window. |
| 04:51 | Once the solving is done, type "paraFoam" to view the results. |
| 04:55 | On the left hand side of the Object Inspector menu, click Apply to view the geometry. |
| 05:01 | Scroll down the properties panel of the Object Inspector menu for time step, regions and fields. |
| 05:08 | To view the contours from the top drop down menu, in the Active Variable Control menu, change from solid color to capital 'U'. |
| 05:19 | You can see the initial condition of the velocity. |
| 05:23 | Now on top of the ParaView window, you will see the VCR control. |
| 05:28 | Click on the Play button. |
| 05:33 | You will see the contour of Pressure or Velocity on the flat plate accordingly. |
| 05:39 | This is the velocity contour. Toggle on the Color legend. |
| 05:43 | To do this, click on the color legend icon on the Active Variable Control menu. |
| 05:50 | Click Apply in the Object inspector menu. |
| 05:53 | In the Object inspector menu, click on Display. |
| 05:57 | Scroll down and click on Rescale to data range. |
| 06:03 | Let me shift this Color legend on top to visualize the Vector Plot. Go to the Filters Menu > Common > glyph. |
| 06:15 | Go to the Properties in Object Inspector menu. |
| 06:20 | Click Apply on the left hand side of Object Inspector Menu. |
| 06:24 | You can change the number of vectors by changing their size at the bottom. |
| 06:29 | Also, the size of the vectors can be changed by clicking on the Edit button. The set scale factor can be changed to 0.1 |
| 06:41 | Again, click the Apply button. |
| 06:44 | Now let me zoom this. |
| 06:46 | To do this, in the Active Variable Control menu, click on zoomToBox option. |
| 06:52 | And zoom over any area that you desire. |
| 06:58 | We can see the parabolic variation of vector plot as the flow moves over the plate. |
| 07:04 | Delete this. Now delete the vector plot. |
| 07:09 | Also, we can see that the color near to 1 corresponds to the velocity of 0.99 times the free stream velocity. |
| 07:17 | You can also plot the variation of velocity along the X and Y axes using the plot data over line. |
| 07:26 | This brings us to the end of the tutorial. In this tutorial, we learnt:
|
| 07:37 | As an Assignment-
Create a geometry of flow over a flat plate. Refine the grid spacing near the plate. |
| 07:45 | 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. |
| 07:55 | The Spoken Tutorial Project team"
For more details, please write to: contact@spoken-tutorial.org |
| 08:08 | Spoken Tutorial project is a part of the Talk to a Teacher project. It is supported by the National Mission on Education through ICT, MHRD, Government of India. |
| 08:17 | More information on this mission is available at this URL: http://spoken-tutorial.org/NMEICT-Intro.
This is Rahul Joshi from IIT Bombay, signing off. Thanks for joining. |
