OpenFOAM/C3/Flow-over-a-flat-plate/English

Tutorial: Flow over a flat plate using OpenFOAM.

Script and Narration: Rahul Joshi

Keywords: Video tutorial, CFD, Flat plate, Boundary layer, glyph (vector plotting).

Visual Cue	Narration
Slide 1	Hello and welcome to the spoken tutorial on Flow over a flat plate using OpenFOAM.
Slide 2 : Learning Objectives	In this tutorial I will teach you about the Geometry of the flat plate I will also show you how to Change the grid spacing in meshing Post Process results in ParaView and Visualise using Vector Plot.
Slide 3: System Requirement	To record this tutorial I am using Linux Operating system Ubuntu version 12.04. OpenFOAM version 2.1.1 ParaView version 3.12.0
Slide 4:	Flow over flat plate is a fundamental problem in fluid mechanics
Slide 5: Flow over a flat plate diagram	We can visualise the growth of boundary layer Boundary layer is a very thin region above the body where the velocity is 0.99 times the free stream velocity.
Slide 6: Diagram of boundary conditions.	This is a diagram of flow over the flat plate The boundary conditions are given as follows You have the Inlet Plate Top – which is the Farfield and Outlet –which is the pressure outlet boundary Free stream velocity U = 1 m/s, and We are solving this for Reynolds no (Re) = 100
Click on home>> OpenFoam >> Run >> Tutorials >> Incompressible >> SimpleFoam	Go to the home folder and click on the OpenFoam folder Then go to the Run directory You will see Tutorials. Click on it. Scroll down and then click on Incompressible. Scroll down. You will see the simpleFoam folder. Click on it This solver suits our case.
Right click >> Create new folder >> flatplate	In this, create a folder by the name flatplate. Right click - Create New Folder - flatplate
Double-click pitzdaily folder	Now, let's open the pitzdaily case.
Zoom in	Let me zoom this.
Select 0, constant and system folders	Copy the three folders - 0, constant and system
Copy them	Copy this
Go back to SimpleFoam >> flatplate folder Paste them there	Now let us go one level back. Paste these folders inside the flatplate folder.
Click on constant >> polyMesh	Open the constant folder and then the polyMesh folder
	Change the geometry and boundary condition names in the blockMeshDict file.
	I have already made the changes. Let us open the blockMeshDict file The geometry is in meters.
	We have set the dimensions of the flatplate
Simplegrading (1 3 1)	We can see that simpleGrading. It is kept as (1 3 1) as we need a finer mesh near the plate.
	Now close this. Go two levels back.
	Similarly, make changes in the boundary condition names inside the files in the 0 folder. These files have pressure, velocity and wall functions.
	To calculate the values of wall functions, please refer to the earlier tutorials in the OpenFoam series. Let us go one level back.
	The system folder can be kept default Let us close this
Open the terminal window : Press Ctrl+Alt+t keys simultaneously	Now let us open the terminal window. In the terminal window, type run and press Enter.
Type cd tutorials	Type cd space tutorials and press Enter.
Type cd incompressible	Type cd incompressible press Enter.
Type cd simpleFoam	Type cd space simpleFoam press Enter.
Type ls	Now type ls and press Enter.
	We can see the flatplate folder.
Type cd flatplate	Now type cd space flatplate and press Enter.
Type ls	Now type ls and press Enter.
	You can see the three folders 0,constant and system.
Type blockMesh	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.
	Press Enter. Meshing has been done.
	Note that if there is some error in the blockMesh file, it will be shown in the terminal window.
Type paraFoam	To view the geometry, type “paraFoam” and press Enter.
Paraview window click on APPLY button on left hand side	After the ParaView window opens, on the left hand side of the object inspector menu, click Apply. We can see the geometry. Close the ParaView window. Let me switch back to the slides.
Slide 6 : solver	The solver we are using here is: simpleFoam. SimpleFoam is a steady state solver for incompressible and turbulent flows
Demo : type simpleFoam	Let me switch back to the terminal window. In the terminal window ,type simpleFoam and press Enter. You will see the iterations running in the terminal window.
Type paraFoam	Once the solving is done, type paraFoam to view the results.
In the Paraview window click on APPLY button on left hand side	On the left hand side of the Object Inspector menu, click Apply to view the geometry.
Properties	Scroll down the properties panel of the Object Inspector menu for time step, regions and fields
Change the drop down menu from Solid Color to U	To view the contours from the top drop down menu, in the Active Variable Control menu, change from solid color to capital U
	You can see the initial condition of velocity
VCR control	Now on top of the ParaView window, you will see the VCR controls.
Click on Play button of VCR control	Click on the Play button.
	You will see the contour of Pressure or Velocity on the flat plate accordingly
Toggle on the Colour legend	This is the velocity contour Toggle on the Color legend
Color legend left hand side top icon	To do this, click on the colour legend icon in the Active Variable Control menu
Clcik on APPLY button	Click Apply in the Object inspector menu
Click on Display	In the Object inspector menu, click on Display
Click on rescale to data range	Scroll down and click on Rescale to data range
Shift color legend on top of the geometry	Let me shift this Color legend on top
Top menu >> Filter > Commom > glyph	To visualize the Vector Plot, go to the Filters Menu > Common > glyph
	Go to the Properties in Object Inspector menu
	Click Apply on the left hand side of Object Inspector Menu.
Changing vector size	You can change the number of vectors by changing their size at the bottom.
Scroll down and click on edit button set scale factor 0.1	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
Click the apply button	Again, click the Apply button.
	Now let me zoom this
Click on ZoomToBox icon	To do this, in the Active Variable Control menu, click on zoomToBox option
	And zoom over any area that you desire
Parabolic variation of vector plot	We can see the parabolic variation of vector plot as the flow moves over the plate.
Delete the vector plot	Delete this. Now delete the vector plot.
Correesponding to color of 1 in color legend	Also, we can see that the color near to 1 corresponds to the velocity of 0.99 times the free stream velocity.
To plot the data along x and y axis	You can also plot the variation of velocity along the x and y axes using the plot data over line.
Slide 9 Summary	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
Slide 10: Assignment	As an Assignment, Create a geometry of flow over a flat plate Refine the grid spacing near the plate
Slide 11 : About Spoken tutorials	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.
Slide 12: About Spoken tutorials	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
Slide 13: Acknowledgement	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. More information on this mission is available at this URL http://spoken-tutorial.org/NMEICT-Intro
About the contributor	This is Rahul Joshi from IIT BOMBAY signing off. Thanks for joining.

Contributors and Content Editors

DeepaVedartham, Nancyvarkey, Rahuljoshi, Sneha