Difference between revisions of "OpenFOAM/C2/2D-Laminar-Flow-in-a-channel/English-timed"

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| 00:09
 
| 00:09
 
| In this tutorial, I will show you-  
 
| In this tutorial, I will show you-  
−
* '''2D geometry of channel '''
+
* '''2D geometry''' of '''channel'''  
−
* '''Meshing the Geometry'''
+
* '''Meshing''' the '''Geometry'''
 
* '''Solving''' and '''Post Processing results''' in '''Paraview''' and
 
* '''Solving''' and '''Post Processing results''' in '''Paraview''' and
−
* Validation using '''analytic result'''.
+
* '''Validation''' using '''analytic result'''.
  
 
|-
 
|-
 
| 00:25
 
| 00:25
 
| To record this tutorial, I am using:
 
| To record this tutorial, I am using:
−
* '''Linux Operating system Ubuntu''' 12.04.
+
* '''Linux Operating system Ubuntu''' version 12.04.
 
* '''OpenFOAM''' version 2.1.1
 
* '''OpenFOAM''' version 2.1.1
 
* '''ParaView''' version 3.12.0  
 
* '''ParaView''' version 3.12.0  
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|-
 
|-
 
| 00:39
 
| 00:39
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|Note that '''OpenFOAM''' version 2.1.1 is supported on '''ubuntu version''' 12.04.
+
|Note that '''OpenFOAM''' version 2.1.1 is supported on '''ubuntu''' version 12.04.
  
 
|-
 
|-
 
| 00:45
 
| 00:45
−
|Hence forth all the tutorials will be covered using '''OpenFOAM ''' version 2.1.1 and''' ubuntu version''' 12.04.
+
|Hence forth all the tutorials will be covered using '''OpenFOAM ''' version 2.1.1 and''' ubuntu''' version 12.04.
  
 
|-
 
|-
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|-
 
|-
 
| 01:09
 
| 01:09
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|we simulate flow in a channel to determine flow development length along the downstream '''Channel flow''' problem description.
+
|We simulate flow in a channel to determine flow development length along the downstream.
 +
'''Channel flow''' problem description.
  
 
|-
 
|-
 
| 01:19
 
| 01:19
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| The '''boundary names''' and the '''inlet conditions''' are shown in this figure.
+
| The '''boundary''' names and the '''inlet conditions''' are shown as in this figure.
  
 
|-
 
|-
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|-
 
|-
 
| 01:37
 
| 01:37
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| Using the formula, length of the '''channel''' comes out to be 5 meters and height is kept as 1 meter.
+
| Using the formula, the length of the '''channel''' comes out to be 5 meters and height is kept as 1 meter.
  
 
|-
 
|-
 
| 01:45
 
| 01:45
−
|The '''Inlet velocity''' is 1 meters per second. And, we are solving this for a '''Reynolds number''' '''( Re ) equal 100'''.
+
|The '''Inlet velocity''' is 1 meter per second. And, we are solving this for a '''Reynolds number''' ( Re ) equal to 100.
  
 
|-
 
|-
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|-
 
|-
 
| 02:25
 
| 02:25
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| Copy '''0, Constant''' and '''System''' folders of any other case file in the '''simpleFoam''' directory.
+
| Copy '''0, Constant''' and '''System''' folders of any other case, in the '''simpleFoam''' directory.
  
 
|-
 
|-
 
| 02:34
 
| 02:34
−
| I have copied the''' file structure''' of the case of''' pitzDaily'''.
+
| I have copied the file structure of the case ''' pitzDaily'''.
  
 
|-
 
|-
 
| 02:38
 
| 02:38
−
| Paste it inside the '''channel''' folder  and make the necessary changes in the '''geometry''','''boundary faces''' and '''boundary condition'''.
+
| Paste it inside the '''channel''' folder  and make the necessary changes in the '''geometry''', '''boundary faces''' and '''boundary condition'''.
  
 
|-
 
|-
 
| 02:48
 
| 02:48
−
| Now, let me open the command terminal.
+
| Now, let me open the '''command terminal'''.
  
 
|-
 
|-
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|-
 
|-
 
| 02:57
 
| 02:57
−
| In the terminal, type '''run''' and press '''Enter'''.
+
| In the terminal, type "run" and press '''Enter'''.
  
 
|-
 
|-
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|-
 
|-
 
| 03:20
 
| 03:20
−
| Now type '''cd channel''' and press '''Enter'''.
+
| Now type '''cd space channel''' and press '''Enter'''.
  
 
|-
 
|-
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|-
 
|-
 
| 03:33
 
| 03:33
−
| You will see three folders '''0, Constant''' and '''System'''.
+
| You will see three folders '''0, Constant''' and '''system'''.
  
 
|-
 
|-
 
| 03:37
 
| 03:37
−
| Now type '''cd constant''' and press '''Enter'''.
+
| Now type '''cd space constant''' and press '''Enter'''.
  
 
|-
 
|-
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|-
 
|-
 
| 03:52
 
| 03:52
−
| In this, you will see files containing properties of fluid and a folder named '''polymesh'''.
+
| In this, you will see the files containing properties of fluid and a folder named '''polymesh'''.
  
 
|-
 
|-
 
| 03:59
 
| 03:59
−
| '''RASProperties''' contains '''Reynolds-averaged stress '''model.
+
| '''RASProperties''' contains '''Reynolds-averaged stress model'''.
  
 
|-
 
|-
 
|04:03
 
|04:03
−
| '''transportProperties''' contains the '''transport model '''and '''kinematic viscosity''' that is (nu), in this case is set at 0.001 m²/s.
+
| '''transportProperties''' contains the '''transport model '''and '''kinematic viscosity''' that is (nu), in this case is set at 0.01 m²/s.
  
 
|-
 
|-
 
| 04:17
 
| 04:17
−
| Now in terminal, type '''cd polyMesh''' and press '''Enter'''. Now, type "ls" and press '''Enter'''.
+
| Now in terminal, type '''cd space polyMesh''' and press '''Enter'''. Now, type "ls" and press '''Enter'''.
  
 
|-
 
|-
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|-
 
|-
 
| 04:33
 
| 04:33
−
| To open up the '''blockMeshDict''' file, in the terminal, type "gedit blockMeshDict" and press '''Enter''', scroll down.
+
| To open up the '''blockMeshDict''' file, in the terminal, type "gedit space blockMeshDict" and press '''Enter'''. Scroll down.
  
 
|-
 
|-
 
| 04:48
 
| 04:48
−
| The geometry is in meters. So, the '''convertTometers''' is set to 1. Next, we have defined the vertices of the channel.  
+
| The geometry is in meters. So, the '''convertTometers''' is set to 1. Next, we have defined the vertices of the '''channel'''.  
  
 
|-
 
|-
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|-
 
|-
 
| 05:07
 
| 05:07
−
| Next, we have setup the '''boundary conditions''' and their types which are '''inlet, outlet, top and bottom '''.
+
| Next, we have setup the '''boundary conditions''' and their types which are '''inlet, outlet, top''' and '''bottom'''.
  
 
|-
 
|-
 
| 05:19
 
| 05:19
−
| As this is a 2D Geometry,  front and Back''' are  kept as '''empty'''.
+
| As this is a 2D Geometry,  '''front and Back''' are  kept as '''empty'''.
  
 
|-
 
|-
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|-
 
|-
 
| 05:38
 
| 05:38
−
| In the '''command terminal''', type '''cd space ..(dot dot) '''and press '''Enter'''.  
+
| In the command terminal, type '''cd space ..(dot dot) '''and press '''Enter'''.  
  
 
|-
 
|-
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|-
 
|-
 
| 05:49
 
| 05:49
−
| Now. in the terminal. type '''cd space 0 (Zero)''' and press '''Enter'''. Now, type "ls" and press '''Enter'''.
+
| Now. in the terminal, type '''cd space 0 (Zero)''' and press '''Enter'''. Now, type "ls" and press '''Enter'''.
  
 
|-
 
|-
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|-
 
|-
 
| 06:24
 
| 06:24
−
| Calculate 'k' which is the '''turbulent kinetic energy''' from the formula given in the slide.
+
| Calculate 'k' which is the '''turbulent kinetic energy''' from the formula given in the slide
  
 
|-
 
|-
 
| 06:29
 
| 06:29
−
|Where Ux, Uy and Uz are the '''velocity''' '''components in the x, y and z directions and''' U' ( dash ) = 0.05''' times '''u''' actual.
+
|where Ux, Uy and Uz are the '''velocity''' '''components in the x, y and z directions and''' U' ( dash ) = 0.05''' times '''u''' actual.
  
 
|-
 
|-
 
| 06:43
 
| 06:43
−
| Calculate '''epsilon''' from the formula given where epsilon is the''' rate of dissipation turbulent  energy''', '''C mu''' is a '''constant''' and its value is 0.09.
+
| Calculate '''epsilon''' from the formula given where epsilon is the''' rate of dissipation of turbulent  energy''', '''C mu''' is a '''constant''' and its value is 0.09.
  
 
|-
 
|-
 
| 06:56
 
| 06:56
−
|And''' l''' is the length of the '''channel'''. Let me minimize this.
+
|And 'l' is the length of the '''channel'''. Let me minimize this.
  
 
|-
 
|-
 
| 07:02
 
| 07:02
−
| Change only the '''boundary names''' in each of the above '''folder'''.
+
| Change only the '''boundary names''' in each of the above files.
  
 
|-
 
|-
 
| 07:07
 
| 07:07
−
| Note that the values of '''nut, nuTilda and R ''' are to kept default.
+
| Note that the values of '''nut, nuTilda, R ''' are kept to default.
  
 
|-
 
|-
 
|07:13
 
|07:13
−
| Rest of the files should contain initial value for each of the '''boundary faces'''.
+
| Rest of the files should contain the initial value for each of the '''boundary faces'''.
  
 
|-
 
|-
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|-
 
|-
 
| 07:40
 
| 07:40
−
|'''Meshing''' is done. Now let me switch back to the '''slide'''.
+
| The '''Meshing''' is done. Now let me switch back to the '''slide'''.
  
 
|-
 
|-
 
| 07:45
 
| 07:45
−
| The type of '''solver''' we are using here is '''SimpleFoam'''. It is a '''Steady-state''' solver for '''in-compressible, turbulent flow'''.
+
| The type of '''solver''' we are using here is '''SimpleFoam'''. It is a '''Steady-state''' solver for in-compressible and turbulent flows.
  
 
|-
 
|-
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|-
 
|-
 
| 08:20
 
| 08:20
−
|type "paraFoam" and press '''Enter'''. This will open up the '''paraview''' window.
+
|type "paraFoam" and press '''Enter'''. This will open up the '''paraView''' window.
  
 
|-
 
|-
 
| 08:28
 
| 08:28
−
| On left hand side of the '''paraView''' window, click '''Apply'''. The geometry can be seen here.
+
| On the left hand side of the '''paraView''' window, click '''Apply'''. The geometry can be seen here.
  
 
|-
 
|-
 
| 08:35
 
| 08:35
−
| On top of '''active variable control''' menu, change the drop down menu from '''solid color''' to capital '''U'''.
+
| On top of the '''active variable control''' menu, change the drop down menu from '''solid color''' to capital '''U'''.
  
 
|-
 
|-
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|-
 
|-
 
| 09:36
 
| 09:36
−
| The results obtained can be validated with the analytical solution for '''laminar flow''', in a'''channel''' which is u(max)=1.5 Uavg.
+
| The results obtained can be validated with the analytical solution for '''laminar flow''' in a'''channel''' which is u(max)=1.5 Uavg.
  
 
|-
 
|-
 
| 09:46
 
| 09:46
−
|Using '''openFoam''', we obtain a velocity of 1.48 meters per second which is a good match.  
+
|Using '''openFoam''', we obtain a result of u(max) = 1.48 meters per second which is a good match.  
 
This brings us to the end of the tutorial.
 
This brings us to the end of the tutorial.
  
 
|-
 
|-
 
| 09:57
 
| 09:57
−
| In this tutorial, we learnt the File structure of '''channel''',  
+
| In this tutorial, we learnt the file structure of '''channel''', obtained solution using '''steady state solver'''. Viewed the geometry in '''paraview ''' and '''validation''' with '''analytic results'''.
−
obtained solution using '''steady state solver'''.
+
−
 
+
−
Viewed the geometry in '''paraview ''''''Validation''' with '''analytic results'''
+
  
 
|-
 
|-
 
| 10:08
 
| 10:08
 
| As an assignment-  
 
| As an assignment-  
−
solve the problem for '''Reynold Number 1500''' and '''validate''' it with the analytical result.
+
solve the problem for '''Reynold's Number equal to 1500''' and '''validate''' it with the analytical result.
  
 
|-
 
|-
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|-
 
|-
 
| 10:52
 
| 10:52
−
|More information on the same is available at the following URL link:
+
|More information on this mission  is available at the following URL link:
 
http://spoken-tutorial.org/NMEICT-Intro
 
http://spoken-tutorial.org/NMEICT-Intro
  

Revision as of 16:01, 27 June 2016

Time Narration
00:01 Hello and welcome to the spoken tutorial on Simulating 2D Laminar Flow in a Channel using OpenFoam.
00:09 In this tutorial, I will show you-
  • 2D geometry of channel
  • Meshing the Geometry
  • Solving and Post Processing results in Paraview and
  • Validation using analytic result.
00:25 To record this tutorial, I am using:
  • Linux Operating system Ubuntu version 12.04.
  • OpenFOAM version 2.1.1
  • ParaView version 3.12.0
00:39 Note that OpenFOAM version 2.1.1 is supported on ubuntu version 12.04.
00:45 Hence forth all the tutorials will be covered using OpenFOAM version 2.1.1 and ubuntu version 12.04.
00:56 As a prerequisite for this tutorial, you should know how to create geometry using OpenFOAM.
01:03 If not, please refer to the relevant tutorials on our website.
01:09 We simulate flow in a channel to determine flow development length along the downstream.

Channel flow problem description.

01:19 The boundary names and the inlet conditions are shown as in this figure.
01:26 The flow develpoment length is given by the formula L= 0.05 * Re * D.
01:32 'Re' which is the Reynolds number and 'D' which is the channel height.
01:37 Using the formula, the length of the channel comes out to be 5 meters and height is kept as 1 meter.
01:45 The Inlet velocity is 1 meter per second. And, we are solving this for a Reynolds number ( Re ) equal to 100.
01:53 This is a steady state problem . Therefore we are using a steady state incompressible solver for this case.
02:01 This is the file structure of our case. The folder should be created in the solver type that we choose. I have already created a folder in simpleFoam folder of incompressible flow solvers.
02:18 The folder is named as channel. Now, let me switch to the folder.
02:25 Copy 0, Constant and System folders of any other case, in the simpleFoam directory.
02:34 I have copied the file structure of the case pitzDaily.
02:38 Paste it inside the channel folder and make the necessary changes in the geometry, boundary faces and boundary condition.
02:48 Now, let me open the command terminal.
02:51 To do this, press Ctrl+Alt +t keys simultaneously on your keyboard.
02:57 In the terminal, type "run" and press Enter.
03:01 Now type cd space tutorials and press Enter.
03:08 Now type cd space incompressible and press Enter.
03:15 Type cd space simpleFoam and press Enter.
03:20 Now type cd space channel and press Enter.
03:28 Now, type "ls" and press Enter.
03:33 You will see three folders 0, Constant and system.
03:37 Now type cd space constant and press Enter.
03:48 Now type "ls" and press Enter.
03:52 In this, you will see the files containing properties of fluid and a folder named polymesh.
03:59 RASProperties contains Reynolds-averaged stress model.
04:03 transportProperties contains the transport model and kinematic viscosity that is (nu), in this case is set at 0.01 m²/s.
04:17 Now in terminal, type cd space polyMesh and press Enter. Now, type "ls" and press Enter.
04:30 You will see the blockMeshDict file here.
04:33 To open up the blockMeshDict file, in the terminal, type "gedit space blockMeshDict" and press Enter. Scroll down.
04:48 The geometry is in meters. So, the convertTometers is set to 1. Next, we have defined the vertices of the channel.
04:59 We have used a 100 X 100 mesh size here and cell spacing is kept as ( 1 1 1 ).
05:07 Next, we have setup the boundary conditions and their types which are inlet, outlet, top and bottom.
05:19 As this is a 2D Geometry, front and Back are kept as empty.
05:27 Also, this being a simple geometry, mergePatchPair and edges are to be kept empty. Close the blockMeshDict file.
05:38 In the command terminal, type cd space ..(dot dot) and press Enter.
05:44 Again, type cd space .. (dot dot) and press Enter.
05:49 Now. in the terminal, type cd space 0 (Zero) and press Enter. Now, type "ls" and press Enter.
05:58 This contains the intial boundary conditions and wall functions for the channel case.
06:05 It should contain various files such as epsilon, k, nut, nuTilda which are the wall functionsand 'p' , 'R' and capital 'U' which are initial conditions of the flow.
06:20 Let me switch back to the slides.
06:24 Calculate 'k' which is the turbulent kinetic energy from the formula given in the slide
06:29 where Ux, Uy and Uz are the velocity components in the x, y and z directions and U' ( dash ) = 0.05 times u actual.
06:43 Calculate epsilon from the formula given where epsilon is the rate of dissipation of turbulent energy, C mu is a constant and its value is 0.09.
06:56 And 'l' is the length of the channel. Let me minimize this.
07:02 Change only the boundary names in each of the above files.
07:07 Note that the values of nut, nuTilda, R are kept to default.
07:13 Rest of the files should contain the initial value for each of the boundary faces.
07:21 Now, in the terminal, type cd (space) ..(dot dot) and press Enter.
07:27 There are no changes to be done in the system folder.
07:31 Now we need to mesh the geometry. To do this, in the command terminal, type "blockMesh" and press Enter.
07:40 The Meshing is done. Now let me switch back to the slide.
07:45 The type of solver we are using here is SimpleFoam. It is a Steady-state solver for in-compressible and turbulent flows.
07:55 Let me minimize this.
07:56 In the command terminal, type "simpleFoam" and press Enter.
08:03 Iterations running will be seen in the command terminal.
08:07 Iterations running may take some time.
08:11 The iterations will stop once the solution is converged or it reaches its end time value.
08:16 To view the results in paraView, in the terminal,
08:20 type "paraFoam" and press Enter. This will open up the paraView window.
08:28 On the left hand side of the paraView window, click Apply. The geometry can be seen here.
08:35 On top of the active variable control menu, change the drop down menu from solid color to capital U.
08:50 You can see the initial state of velocity magnitude at inlet.. On top of the paraView window, click on theplay button of the VCR control.
09:00 you can see the final value of the velocity magnitude.
09:07 Also toggle on the color legend from the left hand side top of active variable control menu, click APPLY again.
09:16 Now go to Display, scroll down. You can see Rescale, click on it.
09:24 We can see that once the flow has fully developed, it attains a maximum uniform velocity at the center. Now, let me switch back to the slides.
09:36 The results obtained can be validated with the analytical solution for laminar flow in achannel which is u(max)=1.5 Uavg.
09:46 Using openFoam, we obtain a result of u(max) = 1.48 meters per second which is a good match.

This brings us to the end of the tutorial.

09:57 In this tutorial, we learnt the file structure of channel, obtained solution using steady state solver. Viewed the geometry in paraview and validation with analytic results.
10:08 As an assignment-

solve the problem for Reynold's Number equal to 1500 and validate it with the analytical result.

10:17 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.

10:28 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

10:42 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.
10:52 More information on this mission is available at the following URL link:

http://spoken-tutorial.org/NMEICT-Intro

10:57 This is Rahul Joshi from IIT Bombay, signing off. Thanks for joining.

Contributors and Content Editors

DeepaVedartham, PoojaMoolya, Pratik kamble, Sandhya.np14

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