Difference between revisions of "OpenFOAM-version-7/C3/Simulating-1D-Conduction-through-a-Bar/English"

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|| Slide: '''Code Files'''
 
|| Slide: '''Code Files'''
 
||  
 
||  
−
* The files used in this tutorial are provided in the '''Code''' '''Files''' link on this tutorial page  
+
* The files used in this tutorial are provided in the '''Code Files''' link on this tutorial page  
 
* Please download and extract them
 
* Please download and extract them
 
* Make a copy and then use them while practising
 
* Make a copy and then use them while practising
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'''Geometry'''
 
'''Geometry'''
 
|| We will be solving a '''1D Conduction Problem'''.
 
|| We will be solving a '''1D Conduction Problem'''.
−
* The bar is '''1 meter '''long.
+
* The bar is 1 meter long.
  
 
|-  
 
|-  
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||  
 
||  
 
* The '''left face''' is maintained at a higher temperature compared to the '''right face'''.
 
* The '''left face''' is maintained at a higher temperature compared to the '''right face'''.
 +
 
* The '''top''' and '''bottom faces''' of the bar are '''adiabatic'''.
 
* The '''top''' and '''bottom faces''' of the bar are '''adiabatic'''.
 +
 
* According to '''Fourier’s Law''', we expect the flow of temperature from left to right.
 
* According to '''Fourier’s Law''', we expect the flow of temperature from left to right.
 +
 
* We will simulate this case using the '''laplacianFoam solver'''.
 
* We will simulate this case using the '''laplacianFoam solver'''.
  
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|-  
 
|-  
 
|| CTRL + ALT + T
 
|| CTRL + ALT + T
−
|| Open the '''terminal''' by pressing '''Ctrl''', '''Alt''' & '''T''' keys.
+
|| Open the '''terminal''' by pressing '''Ctrl''', '''Alt''' and '''T''' keys.
 
|-  
 
|-  
 
|| [Terminal] Type:
 
|| [Terminal] Type:
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|-  
 
|-  
 
|| [Terminal]: '''Ctrl + L'''
 
|| [Terminal]: '''Ctrl + L'''
−
|| Press '''Ctrl''' and '''L''' keys together to clear the screen
+
|| Press '''Ctrl''' plus '''L''' keys together to clear the screen.
 
|-
 
|-
 
||Only Narration
 
||Only Narration
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'''cd conductionBar'''
 
'''cd conductionBar'''
−
|| Let’s move into the case folder using the '''cd''' '''command'''.
+
|| Let’s move into the case folder using the '''cd command'''.
 
|-  
 
|-  
 
|| Slide: '''Boundaries'''
 
|| Slide: '''Boundaries'''
 
|| The '''computational domain''' has '''4 boundaries''', namely '''top''', '''bottom''', '''left''', and '''right'''.
 
|| The '''computational domain''' has '''4 boundaries''', namely '''top''', '''bottom''', '''left''', and '''right'''.
  
−
All '''4 boundaries''' are '''fixed'''.
+
All 4 boundaries are fixed.
  
 
|-  
 
|-  
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'''Point to boundary'''
 
'''Point to boundary'''
−
|| The four boundaries '''top, bottom, left''' and '''right''' are defined as type wall.
+
|| The four boundaries '''top, bottom, left''' and '''right''' are defined as '''type wall'''.
  
  
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|| The '''boundary conditions '''used in the '''simulation''' are as shown in the table.
 
|| The '''boundary conditions '''used in the '''simulation''' are as shown in the table.
  
−
* The '''left face''' is maintained at '''373 K''',
+
* The '''left face''' is maintained at 373 '''Kelvin''',
−
* The '''right face''' is maintained at '''273 K''', and
+
* The '''right face''' is maintained at 273 '''Kelvin''', and
 
* The '''top''' and '''bottom faces''' are '''adiabatic'''.  
 
* The '''top''' and '''bottom faces''' are '''adiabatic'''.  
  
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'''internalField uniform 273 '''
 
'''internalField uniform 273 '''
−
|| The '''domain''' is '''initialized''' with a temperature of '''273 K'''.
+
|| The '''domain''' is '''initialized''' with a temperature of '''273 Kelvin'''.
 
|-  
 
|-  
 
|| [gedit - '''T'''] Highlight:  
 
|| [gedit - '''T'''] Highlight:  
  
 
'''bottom '''boundary condition
 
'''bottom '''boundary condition
−
|| The '''left face''' is maintained at a '''constant temperature''' of '''373 K'''.
+
|| The '''left face''' is maintained at a '''constant temperature''' of '''373 Kelvin'''.
 
|-  
 
|-  
 
|| [gedit - '''T'''] Highlight:  
 
|| [gedit - '''T'''] Highlight:  
  
 
'''top '''boundary condition
 
'''top '''boundary condition
−
|| The '''right face''' is maintained at a '''temperature''' of '''273 K'''.
+
|| The '''right face''' is maintained at a '''temperature''' of '''273 Kelvin'''.
 
|-  
 
|-  
 
|| [gedit - '''T'''] Highlight:  
 
|| [gedit - '''T'''] Highlight:  
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|-  
 
|-  
 
|| [Terminal] Type: '''blockMesh'''
 
|| [Terminal] Type: '''blockMesh'''
−
|| First, let’s '''mesh''' the geometry using the '''blockMesh''' '''command'''.
+
|| First, let’s '''mesh''' the geometry using the '''blockMesh command'''.
 
|-  
 
|-  
 
|| [Terminal] Type: '''laplacianFoam'''
 
|| [Terminal] Type: '''laplacianFoam'''
Line 368: Line 371:
  
  
−
||Now, let us plot the temperature''' '''along the length of the rod.
+
||Now, let us plot the temperature along the length of the rod.
  
  
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* Increase the '''length''' of the '''bar''' in the '''x-direction''' to '''2 metres'''
 
* Increase the '''length''' of the '''bar''' in the '''x-direction''' to '''2 metres'''
−
* Change the '''DT '''value to''' 0.005'''
+
* Change the '''DT '''value to 0.005  
 
* Keep all the other parameters unaltered in your '''simulation'''
 
* Keep all the other parameters unaltered in your '''simulation'''
  

Revision as of 17:39, 4 September 2024

Title of the script: Simulating 1-D Conduction through a Bar

Author: Mano Prithvi Raj

Keywords: OpenFOAM, ParaView, CFD, computational fluid dynamics, blockMesh, heat transfer, conduction, laplacianFoam, transport properties, FOSSEE, spoken tutorial, video tutorial


Visual Cue Narration
Slide:

Opening Slide

Welcome to the spoken tutorial on Simulating 1D Conduction through a Bar.
Slide:

Learning Objective

In this tutorial, we will learn to:
  • Set up a case of heat transfer in OpenFOAM
  • Simulate a conduction heat transfer case using a laplacianFoam solver
Slide: System Specifications To record this tutorial, I am using,
  • Ubuntu Linux OS version 22.04
  • OpenFOAM version 9
  • ParaView version 5.6.0, and
  • gedit Text editor

However, you may use any other editor of your choice.

Slide:

Prerequisites


As a prerequisite:
  • You should have basic knowledge of conductive heat transfer.
  • You should be familiar with setting up a case in OpenFOAM.
  • If not, please go through the prerequisite OpenFOAM tutorial on this website.
Slide: Code Files
  • The files used in this tutorial are provided in the Code Files link on this tutorial page
  • Please download and extract them
  • Make a copy and then use them while practising
Slide:

Geometry

We will be solving a 1D Conduction Problem.
  • The bar is 1 meter long.
Slide: Geometry
  • The left face is maintained at a higher temperature compared to the right face.
  • The top and bottom faces of the bar are adiabatic.
  • According to Fourier’s Law, we expect the flow of temperature from left to right.
  • We will simulate this case using the laplacianFoam solver.
Only Narration Let’s look at the structure of laplacianFoam and how its equations are modeled.
Slide: laplacianFoam
  • laplacianFoam is a basic OpenFOAM solver
  • laplacianFoam solves simple Laplace equations
  • An example of such an equation is thermal diffusion in a solid
Slide:

laplacianFoam

Highlight: Laplacian Equation

This is the equation implemented in laplacianFoam:

where,

  • alpha is the thermal diffusivity
  • T is temperature
Point to the equation. Let’s see how this equation is implemented in OpenFOAM
CTRL + ALT + T Open the terminal by pressing Ctrl, Alt and T keys.
[Terminal] Type:

cd $FOAM_SOLVERS

Type the following command and press Enter to move into the solvers directory.
[Terminal] Type:

cd basic/laplacianFoam

Type this command and press Enter to move into the directory of laplacianFoam.
[Terminal] Type: ls Type ls to view the files present in the laplacianFoam directory.
[Terminal] Type:

gedit laplacianFoam.C

Type the following command to open the source code for laplacianFoam.
[gedit laplacianFoam.C] Highlight:

Line no. 62 to 67

This is the code for solving the laplace equation in every timestep.
[gedit laplacianFoam.C] Highlight:

fvm::ddt(T)

The first term represents the time derivative for temperature field T.
[gedit laplacianFoam.C] Highlight:

fvm::laplacian(DT,T)

The second term represents the laplacian of temperature field T.

DT stands for thermal diffusivity.

[gedit laplacianFoam.C] Highlight:

fvModels.source(T)

The last term is on the right hand side of the equation.

It is used to add source terms to the equation.

Click on Close to close the gedit file. Let’s move on to the simulation.

You can now close gedit.

[Terminal] Type:

cd $FOAM_RUN

Type the following command and press Enter to move into the run directory.
[Terminal]: Ctrl + L Press Ctrl plus L keys together to clear the screen.
Only Narration Please remember to press Enter key after typing each command in the terminal.
[Terminal] Type: cp -r ~/Downloads/conductionBar . Copy the case folder that you had downloaded and extracted, into the run directory.
[Terminal] Highlight:


Downloads/conductionBar

In my system, the case folder named conductionBar is located in the Downloads folder.

The location of the case folder may be different for you.

Please use the appropriate command while copying the folder.

[Terminal] Type:

cd conductionBar

Let’s move into the case folder using the cd command.
Slide: Boundaries The computational domain has 4 boundaries, namely top, bottom, left, and right.

All 4 boundaries are fixed.

[Terminal Type]:

gedit system/blockMeshDict

The details of the mesh can be found in the blockMeshDict file in the system folder.


Type the following command to open blockMeshDict in a text editor.

[gedit blockMeshDict]

Point to vertices

These are the vertices used to make a rectangular domain.
[gedit blockMeshDict]

Point to blocks

We have a single block with 20 cells only in the x-direction.
[gedit blockMeshDict]

Point to boundary

The four boundaries top, bottom, left and right are defined as type wall.


The boundary frontAndBack is kept empty as we are doing a 1D simulation.

[gedit blockMeshDict]

Click on Close to close the gedit file

Close the blockMeshDict file.
Slide: Boundary Conditions The boundary conditions used in the simulation are as shown in the table.
  • The left face is maintained at 373 Kelvin,
  • The right face is maintained at 273 Kelvin, and
  • The top and bottom faces are adiabatic.

Therefore, they have zero gradient temperature boundary conditions.

  • The front and back faces are of type empty, as we are running a 1D simulation.


Only Narration Let’s see how the boundary conditions are defined in OpenFOAM.
[Terminal] Type:

ls 0

The boundary conditions are defined in 0 folder.

Let’s view its contents.

[Terminal] Highlight:

T

You’ll see a temperature file.
[Terminal] Type: gedit 0/T Let’s open the temperature file, T.
[gedit - T] Highlight:

internalField uniform 273

The domain is initialized with a temperature of 273 Kelvin.
[gedit - T] Highlight:

bottom boundary condition

The left face is maintained at a constant temperature of 373 Kelvin.
[gedit - T] Highlight:

top boundary condition

The right face is maintained at a temperature of 273 Kelvin.
[gedit - T] Highlight:

left & right boundary condition

The top & bottom have zero gradient temperature boundary condition.
[gedit - T] Highlight:

“faces” “frontAndBack”

Since we are simulating a 1D problem, frontAndBack is set to empty.
[gedit - T] Close the window Close the T file.
[Terminal] Type:

ls constant

Let’s now see the contents of the constant folder using the ls command.
[Terminal] Highlight:

transportProperties

We can see the transportProperties file in the constant folder.
[Terminal] Type: gedit constant/transportProperties Let’s open the transportProperties file.
[gedit - transportProperties] Highlight:

“DT”

In the transportProperties file, we can see a property, DT.

DT stands for thermal diffusivity.

[gedit - transportProperties] Close the window Close the file.
[terminal]: type clear Clear the screen with the clear command.
Only narration Let’s simulate the problem in OpenFOAM.
[Terminal] Type: blockMesh First, let’s mesh the geometry using the blockMesh command.
[Terminal] Type: laplacianFoam Let’s start the simulation using the following command.


[Terminal] Highlight: End The simulation is now complete.
[Terminal] Type: paraFoam Let’s view the simulated results in ParaView.
[ParaView] Properties Tab

Click on Apply

Click on the Apply button to view the geometry.
[ParaView] Active Variable Controls


Click on vtkBlockColors >> Click on T


Let’s view the temperature contours for the simulation.


Click on the vtkBlockColors dropdown in the Active Variable Controls and select T.


Ensure that you click on the T option with a point icon and not the box icon, in the dropdown.

[ParaView] VCR Controls


Click on Last Frame


Let’s view the contours at the end of the simulation.


Click on the Last Frame button in the VCR Controls.

[ParaView] Layout Window


Point to Circulation

We can see the dissipation of heat from the hot end of the bar to the cold end.


The temperature changes linearly as we move from left to the right of the bar.


This is indicated as the color gradually changes from red to blue from left to right.

[ParaView]

Data Analysis => Click on plot over line filter


Now, let us plot the temperature along the length of the rod.


Click on the plot over line icon located on top of the screen as shown.

[ParaView]


Properties Tab => Click on x-axis


&&


Properties Tab => Click on Apply

Click on the x-axis and then click on the Apply button.


As we can see from the graph, the temperature variation is linear.

Only Narration With this we have come to the end of the tutorial.


Let’s summarize.

Slide:

Summary

In this tutorial, we have learnt to:
  • View how laplacian equation is implemented in OpenFoam,
  • Solve heat transfer problem using OpenFoam, and
  • Post-process results in paraview.
Slide:

Assignment

As an assignment:
  • Increase the length of the bar in the x-direction to 2 metres
  • Change the DT value to 0.005
  • Keep all the other parameters unaltered in your simulation
Slide:

Assignment

[next slide of assignment]

  • Simulate the heat transfer through this bar
  • View the temperature contours
  • See how fast the temperature changes with time now.
Slide:

About the Spoken Tutorial Project

The video at the following link summarizes the Spoken Tutorial project.

Please download and watch it.

Slide:

Spoken Tutorial Workshops

We conduct workshops using Spoken Tutorials and give certificates.

Please contact us.

Slide:

Spoken Tutorial Forum

Please post your timed queries in this forum.
Slide:

FOSSEE Forum

  • Do you have any general/technical questions?
  • Please visit the forum given in the link.
Slide:

FOSSEE Case Study Project

  • The FOSSEE team coordinates solving feasible CFD problems of reasonable complexity using OpenFOAM.
  • We give honorarium and certificates to those who do this.
  • For more details, please visit these sites.
Slide: Acknowledgements The Spoken Tutorial project was established by the Ministry of Education, Govt. of India.
Only Narration This tutorial is contributed by Mano Prithvi Raj, Aabhushan Regmi and Payel Mukherjee from IIT Bombay. Thank you for joining.

Contributors and Content Editors

Biraj, Madhurig, Omkar

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