# Difference between revisions of "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
• Geometry of the flat plate
• Changing the grid spacing in meshing
• Post processing results in ParaView and
• Visualizing using Vector Plots
Slide 3:

System Requirement

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
Slide 4:

System Requirement

• The tutorials were recorded using the versions specified in previous slide
• To install latest system requirements go to Installation Sheet
Slide 5: Flow over Flat Plate Flow over flat plate is a fundamental problem in fluid mechanics.
Slide 6: Flow over Flat Plate

Flow over a flat plate diagram

We can visualise the growth of the boundary layer.

Boundary layer is a very thin region above the body where the velocity is 0.99 times the free stream velocity.

Slide 7: Diagram of boundary conditions. This is a diagram of the flow over the flat plate.

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
Slide 8: Inlet parameters
• The Free stream velocity U is 1 m/s, and
• We are solving this for a Reynolds number (Re) = 100
Click on Home>> OpenFoam Now let us go to the Home folder.

In the Home folder, click on the OpenFoam folder.

Click on Run >> Tutorials Then go to the Run directory.

You will see Tutorials. Click on it.

Click on Incompressible >> SimpleFoam 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 us open the pitzdaily case.
Zoom in Let me zoom this.
Select 0,constant and system folders Copy the three folders 0, constant and system.
Ctrl + C. Copy this.
Go back to SimpleFoam >> flatplate folder.

Paste them there.

Now let us go one level back.

Paste these three 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.
Open blockMeshDict file >> Scroll down. I have already made the changes.

Let us open the blockMeshDict file. Scroll down.

The geometry is in meters.

We have set the dimensions of the flatplate.

It is kept as (1 3 1) as we need a finer mesh near the plate.

Go two levels back Now close this.

Go two levels back.

Make changes in the boundary condition Similarly, make changes in the boundary condition names inside the files in the 0 folder.

These files have pressure, velocity and wall functions.

Go one level back. 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.

Let us 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 Now type cd space tutorials press' Enter.
Type cd incompressible Now type cd incompressible press Enter.
Type cd simpleFoam Now 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 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. Close the ParaView window.

Let me switch back to the slides.

Slide 9: 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 drop down menu,
• in the Active Variable Control menu,
• change from solid color to capital U
You can see the initial condition of the velocity.
VCR control Now on top of the ParaView window, you will see the VCR control.
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 Color legend This is the velocity contour.

Toggle on the Color legend.

Color legend left hand side top icon To do this, click on the color legend icon on the Active Variable Control menu.
Click 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 > Common > glyph To visualize the Vector Plot,

go to the Filters Menu > Common > glyph

Go to Properties Go to the Properties in Object Inspector menu.
Click Apply 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 the zoomToBox option.
And zoom over any area that you desire.
Parabolic variation of vector plot We can see the parabolic variation of vector plots as the flow moves over the plate.
Delete the vector plot Delete this. Now delete the vector plot.
Corresponding 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 We can also plot the variation of velocity along the x and y axes using the plot data over line.
Slide 10: 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 11: Assignment As an assignment,

Create a geometry of flow over the flat plate.

Refine the grid spacing near the plate.

Slide 12 : About Spoken tutorials
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Slide 14: Forum to answer questions
• Do you have questions on THIS Spoken Tutorial?
• Choose the minute and second where you have the question
Slide 15: Forum to answer questions
• Questions not related to the Spoken Tutorial?
• Do you have general/technical questions on the Software?
• Please visit the FOSSEE forum
• Choose the Software and post your question
Slide 16: Lab Migration Project
• We coordinate migration from commercial CFD software like ANSYS to OpenFOAM
• We conduct free Workshops and provide solutions to CFD Problem Statements in OpenFOAM

For more details visit this site: http://cfd.fossee.in/

Slide 17: Case Study Project
• We invite students to solve a feasible CFD problem statement of reasonable complexity using OpenFOAM
• We give honorarium and certificate to those who do this

For more details visit this site: http://cfd.fossee.in/

Slide 18:

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

About the contributor This is Rahul Joshi from IIT BOMBAY signing off

Thanks for joining