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

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| 01:26
 
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| The '''flow develpoment length''' is given by the formula '''L= 0.05 * Re * D'''.
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| The '''flow develpoment length''' is given by the formula '''L= 0.05 times Re' that is the '''Reynolds number''' and 'D' which is the '''channel height'''.
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| 'Re' which is the '''Reynolds number''' and 'D' which is the '''channel height'''.
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| It should contain various files such as '''epsilon, k, nut, nuTilda ''' which are the '''wall functions'''and  'p' , 'R' and capital 'U' which  are '''initial conditions''' of the '''flow'''.
 
| It should contain various files such as '''epsilon, k, nut, nuTilda ''' which are the '''wall functions'''and  'p' , 'R' and capital 'U' which  are '''initial conditions''' of the '''flow'''.
  
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| 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
  
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| 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.
 
| 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.
  
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| Note that the values of '''nut, nuTilda, R ''' are kept to default.
 
| Note that the values of '''nut, nuTilda, R ''' are kept to default.
  
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| Now, in the terminal, type '''cd (space) ..(dot dot)''' and press '''Enter'''.
 
| Now, in the terminal, type '''cd (space) ..(dot dot)''' and press '''Enter'''.
  
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|Let me minimize this. In the command terminal, type "simpleFoam" and press '''Enter'''.
 
|Let me minimize this. In the command terminal, type "simpleFoam" and press '''Enter'''.
  
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| The '''iterations''' will stop once the solution is converged or it reaches its '''end time value'''.
 
| The '''iterations''' will stop once the solution is converged or it reaches its '''end time value'''.
  
 
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| 08:16
 
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| To view the results in '''paraView''', in the terminal,  
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| To view the results in '''paraView''', in the terminal, type "paraFoam" and press '''Enter'''. This will open up the '''paraView''' window.
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|type "paraFoam" and press '''Enter'''. This will open up the '''paraView''' window.
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| You can see the '''initial state''' of '''velocity magnitude''' at '''inlet.'''. On top of the '''paraView''' window, click on the'''play''' button of the '''VCR control'''.
 
| You can see the '''initial state''' of '''velocity magnitude''' at '''inlet.'''. On top of the '''paraView''' window, click on the'''play''' button of the '''VCR control'''.
  
 
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|you can see the final value of the '''velocity magnitude'''.
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|You can see the final value of the '''velocity magnitude'''.
  
 
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| 08:59
 
| Also toggle on the '''color legend''' from the left hand side top of '''active variable control''' menu, click '''APPLY''' again.
 
| Also toggle on the '''color legend''' from the left hand side top of '''active variable control''' menu, click '''APPLY''' again.
  
 
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| Now go to '''Display''', scroll down. You can see '''Rescale''', click on it.
 
| Now go to '''Display''', scroll down. You can see '''Rescale''', click on it.
  
 
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| 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.
 
| 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.
  
 
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| 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.
  
 
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|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.
 
|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.
  
 
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| 09:57
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| 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'''.
 
| 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'''.
  
 
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| As an assignment- solve the problem for '''Reynold's Number equal to 1500''' and '''validate''' it with the analytical result.
 
| As an assignment- solve the problem for '''Reynold's Number equal to 1500''' and '''validate''' it with the analytical result.
  
 
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| Watch the video available at this URL:  http://spoken-tutorial.org/What_is_a_Spoken_Tutorial
 
| Watch the video available at this URL:  http://spoken-tutorial.org/What_is_a_Spoken_Tutorial
  
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| The Spoken Tutorial Project team: * Conducts workshops using spoken tutorials.
 
| The Spoken Tutorial Project team: * Conducts workshops using spoken tutorials.
  
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|-
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| '''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.  
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| '''Spoken Tutorials''' is a  part of '''Talk to a Teacher''' project. It is supported by the National Mission on Education through ICT, MHRD, Government of India.  
  
 
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|-
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| 10:52
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| 10:45
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|More information on this mission   is available at the following URL link: http://spoken-tutorial.org/NMEICT-Intro
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|More information on this mission is available at the following URL link: http://spoken-tutorial.org/NMEICT-Intro
  
 
|-
 
|-
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| 10:57
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| 10:50
 
| This is Rahul Joshi from IIT Bombay, signing off. Thanks for joining.
 
| This is Rahul Joshi from IIT Bombay, signing off. Thanks for joining.
  
 
|}
 
|}

Revision as of 11:48, 4 October 2017

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 times Re' that 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.
06:04 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.
06:23 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.
06:42 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.
07:06 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.
07:20 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.
07:54 Let me minimize this. 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.
08:10 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, 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.
08:42 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.
08:53 You can see the final value of the velocity magnitude.
08:59 Also toggle on the color legend from the left hand side top of active variable control menu, click APPLY again.
09:09 Now go to Display, scroll down. You can see Rescale, click on it.
09:17 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.
09:29 The results obtained can be validated with the analytical solution for laminar flow in achannel which is u(max)=1.5 Uavg.
09:39 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.
09:50 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.
10:01 As an assignment- solve the problem for Reynold's Number equal to 1500 and validate it with the analytical result.
10:10 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.

10:21 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

10:35 Spoken Tutorials is a part of Talk to a Teacher project. It is supported by the National Mission on Education through ICT, MHRD, Government of India.
10:45 More information on this mission is available at the following URL link: http://spoken-tutorial.org/NMEICT-Intro
10:50 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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