1 00:00:01 --> 00:00:06 Hello and welcome to the spoken tutorial on Flow over a flat plate using OpenFOAM. 2 00:00:06 --> 00:00:19 In this tutorial I will teach you about Geometry of the flat plate Changing the grid spacing in meshing Post Processing results in ParaView and Visualizing using Vector Plot. 3 00:00:19 --> 00:00:30 To record this tutorial I am using Linux Operating system Ubuntu version 12.04. OpenFOAM version 2.1.1 and ParaView version 3.12.0 4 00:00:30 --> 00:00:35 Flow over flat plate is a fundamental problem in fluid mechanics 5 00:00:35 --> 00:00:41 We can visualise the growth of boundary layer'Boundary layer' is a very thin region above the body 6 00:00:41 --> 00:00:46 where the velocity is 0.99 times the free stream velocity. 7 00:00:46 --> 00:00:49 This is a diagram of flow over the flat plate 8 00:00:49 --> 00:01:00 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 9 00:01:00 --> 00:01:08 The Free stream velocity U = 1 m/s, and we are solving this for Reynolds no (Re) = 100 10 00:01:08 --> 00:01:15 Now let us Go to the home folder in the home folder click on the OpenFoam folder 11 00:01:15 --> 00:01:27 Then go to the Run directory You will see Tutorials. Click on it. Scroll down and then click on Incompressible. Scroll down. 12 00:01:27 --> 00:01:34 You will see the simpleFoam folder.Click on it This solver suits our case. 13 00:01:34 --> 00:01:44 In this, create a folder by the name flatplate.Right click - Create New Folder - flatplate 14 00:01:44 --> 00:01:47 Now, let's open the pitzdaily case. 15 00:01:47 --> 00:01:56 Let me zoom this. Copy the three folders - 0, constant and systemCopy this 16 00:01:56 --> 00:02:05 Now let us go one level back. Paste these three folders inside the flatplate folder. 17 00:02:05 --> 00:02:10 Open the constant folder and then the polyMesh folder 18 00:02:10 --> 00:02:15 Change the geometry and boundary condition names in the blockMeshDict file. 19 00:02:15 --> 00:02:25 I have already made the changes.Let us open the blockMeshDict file . Scroll down The geometry is in meters. 20 00:02:25 --> 00:02:29 We have set the dimensions of the flatplate 21 00:02:29 --> 00:02:35 We can see the simpleGrading. It is kept as (1 3 1) as we need a finer mesh near the plate. 22 00:02:35 --> 00:02:41 Now close this.Go two levels back. 23 00:02:41 --> 00:02:48 Similarly, make changes in the boundary condition names inside the files in the 0 folder. 24 00:02:48 --> 00:02:54 These files have pressure, velocity and wall functions. 25 00:02:54 --> 00:03:03 To calculate the values of wall functions, please refer to the earlier tutorial in the OpenFoam series.Let us go one level back. 26 00:03:03 --> 00:03:09 The system folder can be kept defaultLet us close this 27 00:03:09 --> 00:03:16 Now let us open the terminal window.In the terminal window, type run and press Enter. 28 00:03:16 --> 00:03:21 Type cd space tutorials press' Enter. 29 00:03:21 --> 00:03:25 Type cd incompressible press Enter. 30 00:03:25 --> 00:03:31 Type cd space simpleFoam press Enter. 31 00:03:31 --> 00:03:34 Now type ls and press Enter. 32 00:03:34 --> 00:03:37 We can see the flatplate folder. 33 00:03:37 --> 00:03:42 Now type cd space flatplate and press Enter. 34 00:03:42 --> 00:03:45 Now type ls and press Enter. 35 00:03:45 --> 00:03:49 You can see the three folders 0,constant and system. 36 00:03:49 --> 00:03:58 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. 37 00:03:58 --> 00:04:01 Press Enter. Meshing has been done. 38 00:04:01 --> 00:04:07 Note that if there is some error in the blockMesh file,it will be shown in the terminal window. 39 00:04:07 --> 00:04:13 To view the geometry, type “paraFoam” press Enter. 40 00:04:13 --> 00:04:21 After the ParaView window opens, on the left hand side of the object inspector menu, click Apply. 41 00:04:21 --> 00:04:28 We can see the geometry.Close the ParaView window.Let me switch back to the slides. 42 00:04:28 --> 00:04:37 The solver we are using here is: simpleFoam.'SimpleFoam' is a steady state solver for incompressible and turbulent flows 43 00:04:37 --> 00:04:45 Let me switch back to the terminal window.In the terminal window ,type simpleFoam and press Enter. 44 00:04:45 --> 00:04:51 You will see the iterations running in the terminal window. 45 00:04:51 --> 00:04:55 Once the solving is done, type paraFoam to view the results. 46 00:04:55 --> 00:05:01 On the left hand side of the Object Inspector menu, click Apply to view the geometry. 47 00:05:01 --> 00:05:08 Scroll down the properties panel of the Object Inspector menu for time step, regions and fields 48 00:05:08 --> 00:05:19 To view the contours from the top drop down menu, in the Active Variable Control menu, change from solid color to capital U 49 00:05:19 --> 00:05:23 You can see the initial condition of the velocity 50 00:05:23 --> 00:05:28 Now on top of the ParaView window, you will see the VCR control. 51 00:05:28 --> 00:05:33 Click on the Play button. 52 00:05:33 --> 00:05:39 You will see the contour of Pressure or Velocity on the flat plate accordingly 53 00:05:39 --> 00:05:43 This is the velocity contour Toggle on the Color legend 54 00:05:43 --> 00:05:50 To do this, click on the color legend icon on the Active Variable Control menu 55 00:05:50 --> 00:05:53 Click Apply in the Object inspector menu 56 00:05:53 --> 00:05:57 In the Object inspector menu, click on Display 57 00:05:57 --> 00:06:03 Scroll down and click on Rescale to data range 58 00:06:03 --> 00:06:15 Let me shift this Color legend on top To visualize the Vector Plot, go to the Filters Menu > Common > glyph 59 00:06:15 --> 00:06:20 Go to the Properties in Object Inspector menu 60 00:06:20 --> 00:06:24 Click Apply on the left hand side of Object Inspector Menu. 61 00:06:24 --> 00:06:29 You can change the number of vectors by changing their size at the bottom. 62 00:06:29 --> 00:06:41 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 63 00:06:41 --> 00:06:44 Again, click the Apply button. 64 00:06:44 --> 00:06:46 Now let me zoom this 65 00:06:46 --> 00:06:52 To do this, in the Active Variable Control menu, click on zoomToBox option 66 00:06:52 --> 00:06:58 And zoom over any area that you desire 67 00:06:58 --> 00:07:04 We can see the parabolic variation of vector plot as the flow moves over the plate. 68 00:07:04 --> 00:07:09 Delete this. Now delete the vector plot. 69 00:07:09 --> 00:07:17 Also, we can see that the color near to 1 corresponds to the velocity of 0.99 times the free stream velocity. 70 00:07:17 --> 00:07:26 You can also plot the variation of velocity along the x and y axes using the plot data over line. 71 00:07:26 --> 00:07:37 This brings us to the end of the tutorial.In this tutorial we learnt: Geometry and meshing of the flat plate geometry and Vector plotting in ParaView 72 00:07:37 --> 00:07:45 As an Assignment, Create a geometry of flow over a flat plate Refine the grid spacing near the plate 73 00:07:45 --> 00:07:55 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. 74 00:07:55 --> 00:08:08 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 75 00:08:08 --> 00:08:17 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. 76 00:08:17 --> 00:08:22 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.