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

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Tutorial:Supersonic flow over a wedge using OpenFOAM


Script : Arvind N


Narration: Rahul Joshi


Keywords: Video tutorial,CFD,Wedge,Mach number,Compressible flows.


Visual Cue Narration
Slide 1 Hello and welcome to the spoken tutorial on Supersonic flow over a wedge using OpenFOAM
Slide 2: Learning Objectives In this tutorial I will show you


how to solve a compressible flow problem of supersonic flow over a wedge


how post process the results in paraView.



Slide 3:

System Requirement

To record this tutorial


I am using Linux Operating system Ubuntu version 10.04


OpenFOAM version 2.1.0


ParaView version 3.12.0


Slide:

System Requirement

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


Slide 4

Prerequisites

To practice this tutorial a learner should have some basic knowledge of


Compressible flows and


Gas Dynamics

Slide 5 : Let us now solve supersonic flow over a wedge using OpenFOAM and


see the shock structure formed using paraview

Slide 5 : The problem consists of a wedge


with semi-angle of 15 degrees kept in a


uniform supersonic flow

Inlet velocity 5m/s Inlet velocity is 5 meters per second
Boundary conditions as shown in the figure The boundary conditions are set as shown in the figure



Slide 6 : Solver The type of solver I am using here is rhoCentralFoam
It is a Density-based compressible flow solver


It is based on central- upwind schemes of Kurganov and Tadmor

Switch to the Terminal by Ctrl+Alt+T Open a command terminal


to do this press ctrl +alt+ t keys simultaneously on your keyboard

In the terminal type path for supersonic flow over a wedge
In command terminal:

Type run and press enter


Problem is already set in OpenFOAM

In the terminal Type 'run' and press enter
Type cd tutorial and press enter Now type cd tutorial - Press Enter
Type cd compressible - Press Enter cd compressible - Press Enter
Type cd rhoCentralFoam - Press Enter cd rhoCentralFoam - Press Enter
Type cd wedge and press enter cd wedge15Ma5 and press enter
This is the name of the folder of supersonic flow over a wedge in rhoCentralFoam


and press enter

Type ls now type ls and press enter
You will see three folders : 0,constant and system.
Type cd constant and press enter Now open the blockMeshDict file,


to do this


type cd space constant and press enter

Type cd polyMesh and press enter cd space polyMesh


note that M here is capital


and press enter

Type ls and press enter Now type ls and press enter


you can see the blockMeshDict file



Type gedit blockMeshDict and press enter type gedit space blockMeshDict

note that M and D here are capital


and press enter

let me drag this to the capture area


scroll down

enter the data in vertices but it i already set up in the problem In this you need to calculate the co-ordinates for the wedge


This is already been calculated and set up in the problem

The rest of the data remain the same
Boundary names similar to that in slide 5 In boundary patches the boundaries are set as shown in the figure
Close the blockMeshDict file
type : cd .. (twice) and press enter


wedge folder

in the command terminal


type cd ..(dot dot) twice


to return back to wedge folder

Now Open the 0 folder
Type cd 0 and press enter To do this type


cd space 0 and press enter

type ls and press enter type ls and press enter
this contains initial boundary condition for pressure,velocity and Temprature
type cd .. and press enter type cd .. (dot dot) and press enter
Now we need to mesh the geometry
Mesh the geometry

type: blockMesh

To do this in the command terminal


type blockMesh and Press Enter


Meshing has been done

Terminal : type paraFoam and press enter Now to view the geometry in the terminal


type paraFoam and press enter


This will open the paraview window

Paraview window On the left hand side of object inspector menu click APPLY
About wedge geometry In this you can see the geometry is which is a rectangular


section upstream and changes to a wedge downstream


Close the paraview window

Now run the solver 'rhoCentralFoam'
Terminal : rehoCentralFoam and press enter To do this in the command terminal


type rhoCentralFoam and Press Enter

Iterations in terminal window The iterations running can be seen in the


terminal window

Iterations running will stop after it converges


or


at the end of the time step


Now the solving has been done

open paraview


To visualise these results let us open the


paraview window once again

type: paraFoam and press enter In the command terminal


type “paraFoam” and press Enter

Click APPLY in object inspector menu Again on the left hand side of


object inspector menu click APPLY

Solid geometry in drop down menu


Select U

On the left 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

Make the color legend ON Now make the color legend ON


by clicking on left hand side top of active variable control menu


and make the color legend ON


click on it

On top of the paraview window you can see the VCR control


Click on PLAY

In the paraview window You can see the final results of U velocity
In object inspector menu Now scroll down the


properties in object inspector menu on left hand side


Now click on display besides properties

Click on rescale to size Scroll down and click on Rescale to Size
You can see the final value of Velocity magnitude
Slect pressure in drop dwon menu (p)


Similarly you can select pressure


You can see the final result of pressure


Now close the paraview window

Calculate the Mach number


in terminal type Mach

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

Type mach in terminal


mach number for each time step

Type Mach in the command terminal


Note that M here is capital and press enter


You can see that Mach number is calculated for each time step

Open paraview window


type paraFoam


click APPLY

Now again open the paraview window


By typing in the command terminal paraFoam


and press enter


click APPLY

In object inspector menu

check the Ma check box


change from solid color to Ma

scroll down


In volume fields Check the Ma box and click APPLY


On top of active variable control menu click on Solid Color


and change it to Ma

In VCR control click on play button


make the color legend ON

In the VCR control menu click on PLAY


and make the color legend ON



In paraview window You can see the Mach number in the color legend


and corresponding colours

Slide : For validation 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

Slide ; Summary In this tutorial we learnt:


Solving a compressible flow problem


Velocity and pressure contour for the wedge


OpenFOAM utility for calculating the Mach number

Slide 9 : Assignment Assignment:


Vary the wedge angle between 10 ° to 15 °


to view the shock characteristic for the flow

Slide 10:

About Spoken tutorials

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:

Forum to answer questions

Do you have questions on THIS Spoken Tutorial?

Choose the minute and second where you have the question Explain your question briefly Someone from the FOSSEE team will answer them. Please visit http://forums.spoken-tutorial.org/

Slide:

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 http://forums.fossee.in/ Choose the Software and post your question


Slide:

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:

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 11:

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 us at

contact@spoken-tutorial.org

Slide 12:

Acknowledgement

Spoken Tutorials are 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

About the contributor 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

Chandrika, DeepaVedartham, Nancyvarkey, Rahuljoshi

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