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

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|-
 
|-
 
| 00:01
 
| 00:01
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| Hello and welcome to the spoken tutorial on ''' Simulating 2D Laminar Flow in a Channel using openfoam'''
+
| Hello and welcome to the '''spoken tutorial''' on ''' Simulating 2D Laminar Flow in a Channel''' using '''OpenFoam'''.
  
 
|-
 
|-
 
| 00:09
 
| 00:09
−
| In this tutorial I will show you  
+
| 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'''.
−
'''2D geometry of channel '''
+
−
'''Meshing the Geometry'''  
+
−
'''Solving''' and '''Post Processing results''' in '''Paraview''' and Validation using '''analytic result'''
+
  
 
|-
 
|-
 
| 00:25
 
| 00:25
−
| To record this tutorial I am using '''Linux Operating system Ubuntu 12.04''' .
+
| To record this tutorial, I am using:
−
'''OpenFOAM version 2.1.1'''  
+
 
−
'''ParaView version 3.12.0 '''
+
'''Linux Operating system Ubuntu''' version 12.04. '''OpenFOAM''' version 2.1.1
 +
 
 +
'''ParaView''' version 3.12.0  
 +
 
 +
 
  
 
|-
 
|-
 
| 00:39
 
| 00:39
−
|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.
  
 
|-
 
|-
 
| 00:56
 
| 00:56
−
| As a Pre-requisite for this tutorial You should know how to create '''geometry''' using '''OpenFOAM'''
+
| 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.
  
−
|-
 
−
| 01:03
 
−
|If not, please refer to the '''relevant tutorials''' on our '''website'''
 
  
 
|-
 
|-
−
| 01:09
+
| 01:01
−
|we simulate flow in a channel to determine flow development length along the downstream '''Channel flow''' problem description
+
| As a prerequisite for this tutorial, you should know how to create '''geometry''' using '''OpenFOAM'''.
  
 
|-
 
|-
−
| 01:19
+
| 01:08
−
| The '''boundary names''' and the '''inlet conditions''' are shown in this figure
+
|If not, please refer to the relevant tutorials on our website.
  
 
|-
 
|-
−
| 01:26
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| 01:14
−
| The '''flow develpoment length''' is given by the formula '''L= 0.05 * Re * D'''
+
|We simulate flow in a channel to determine flow development length along the downstream. '''Channel flow''' problem description.
  
 
|-
 
|-
−
| 01:32
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| 01:24
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| '''Re''' which is the '''Reynolds number''' and '''D''' which is the '''channel height'''
+
| The '''boundary''' names and the '''inlet conditions''' are shown as in this figure.
  
 
|-
 
|-
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| 01:37
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| 01:31
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| Using the '''formula''' length of the channel comes out to be '''5 meters '''and '''height''' is kept as '''1 meter'''.
+
| 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'''.
  
 
|-
 
|-
−
| 01:45
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| 01:42
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|The '''Inlet velocity is 1''' '''meters per second''' And we are solving this for a '''Reynolds number''' '''( Re ) equal 100'''
+
| Using the formula, the length of the '''channel''' comes out to be 5 meters and height is kept as 1 meter.
  
 
|-
 
|-
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| 01:53
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| 01:50
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| This is a '''steady state problem '''.Therefore we are using a '''steady state incompressible''' solver for this case
+
|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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| 02:01
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| 01:58
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| 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'''
+
| This is a '''steady state problem '''. Therefore we are using a '''steady state incompressible''' solver for this case.
  
 
|-
 
|-
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| 02:18
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| 02:06
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|The '''folder''' is named as''' channel'''Now let me switch to the '''folder'''
+
| 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'''.
  
 
|-
 
|-
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| 02:25
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| 02:27
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| '''Copy 0,Constant and System''' '''folders''' of any other case file in the '''simpleFoam directory'''
+
|The folder is named as ''' channel'''. Now, let me switch to the folder.
  
 
|-
 
|-
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| 02:34
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| 02:33
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| I have copied the''' file structure''' of the case of''' pitzDaily'''
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| Copy '''0, Constant''' and '''System''' folders of any other case, in the '''simpleFoam''' directory.
  
 
|-
 
|-
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| 02:38
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| 02:42
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| Paste it inside the channel folder  and make the necessary changes in the '''geometry''','''boundary faces''' and '''boundary condition'''
+
| I have copied the file structure of the case ''' pitzDaily'''.
  
 
|-
 
|-
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| 02:48
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| 02:46
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| Now let me '''open the command terminal'''
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| Paste it inside the '''channel''' folder  and make the necessary changes in the '''geometry''', '''boundary faces''' and '''boundary condition'''.
  
 
|-
 
|-
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| 02:51
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| 02:56
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| To do this press '''Ctrl+Alt +t''' keys simultaneously on your '''keyboard'''
+
| Now, let me open the '''command terminal'''.
  
 
|-
 
|-
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| 02:57
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| 02:59
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| In the terminal Type '''run and press enter'''
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| To do this, press '''Ctrl+Alt +t''' keys simultaneously on your keyboard.
  
 
|-
 
|-
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| 03:01
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| 03:05
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| now type cd space '''tutorials and press enter'''
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| In the terminal, type "run" and press '''Enter'''.
  
 
|-
 
|-
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| 03:08
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| 03:09
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| now type cd space '''incompressible and press enter'''
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| Now type '''cd space tutorials''' and press '''Enter'''.
  
 
|-
 
|-
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| 03:15
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| 03:16
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| type cd space '''simpleFoam and press enter'''
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| Now type '''cd space incompressible''' and press '''Enter'''.
  
 
|-
 
|-
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| 03:20
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| 03:23
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| now type cd '''channel and press enter'''
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| Type '''cd space simpleFoam''' and press '''Enter'''.
  
 
|-
 
|-
 
| 03:28
 
| 03:28
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| now type '''ls and press enter'''
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| Now type '''cd space channel''' and press '''Enter'''.
  
 
|-
 
|-
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| 03:33
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| 03:36
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| You will see three folders '''0 , Constant and System'''
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| Now, type "ls" and press '''Enter'''.
  
 
|-
 
|-
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| 03:37
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| 03:41
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| now type cd '''constant and press enter'''
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| You will see three folders '''0, Constant''' and '''system'''.
  
 
|-
 
|-
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| 03:48
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| 03:45
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| now type '''ls and press enter'''
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| Now type '''cd space constant''' and press '''Enter'''.
  
 
|-
 
|-
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| 03:52
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| 03:56
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| In this you will see '''files''' containing '''properties of fluid''' and a''' folder named polymesh'''
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| Now type "ls" and press '''Enter'''.
  
 
|-
 
|-
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| 03:59
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| 04:00
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| '''RASProperties''' contains '''Reynolds-averaged stress '''model
+
| In this, you will see the files containing properties of fluid and a folder named '''polymesh'''.
  
 
|-
 
|-
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|04:03
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| 04:07
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| '''transportProperties''' contain the '''transport model '''and '''kinematic viscosity that is (nu) in this case is set at 0.001 m²/s'''.
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| '''RASProperties''' contains '''Reynolds-averaged stress model'''.
  
 
|-
 
|-
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| 04:17
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| 04:08
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| Now in terminal type '''cd polyMesh and press enter'''.Now type '''ls''' and press enter
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| '''transportProperties''' contains the '''transport model '''and '''kinematic viscosity''' that is (nu), in this case is set at 0.01 m²/s.
  
 
|-
 
|-
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| 04:30
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| 04:25
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|You will see the '''blockMeshDict''' file here
+
| Now in terminal, type '''cd space polyMesh''' and press '''Enter'''. Now, type "ls" and press '''Enter'''.
  
 
|-
 
|-
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| 04:33
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| 04:38
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| To open up the '''blockMeshDict''' file in the terminal '''type gedit blockMeshDict and press enter'''Scroll down
+
|You will see the '''blockMeshDict''' file here.
  
 
|-
 
|-
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| 04:48
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| 04:42
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| The geomery is in '''meters '''so the '''convertTometers''' is set to 1 next we have''' defined''' the '''vertices of the channel '''
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| To open up the '''blockMeshDict''' file, in the terminal, type "gedit space blockMeshDict" and press '''Enter'''. Scroll down.
  
 
|-
 
|-
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| 04:59
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| 04:56
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| We have used a '''100 X 100''' mesh size here and '''cell spacing''' is kept as '''( 1 1 1 )'''
+
| The geometry is in meters. So, the '''convertTometers''' is set to 1. Next, we have defined the vertices of the '''channel'''.
  
 
|-
 
|-
 
| 05:07
 
| 05:07
−
| Next we have setup the '''boundary conditions''' and their types which are '''inlet ,outlet,top and bottom '''
+
| We have used a '''100 X 100 mesh size''' here and '''cell spacing''' is kept as '''( 1 1 1 )'''.
  
 
|-
 
|-
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| 05:19
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| 05:15
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| As this is a '''2D Geometry  front And Back''' are kept as '''empty'''
+
| Next, we have setup the '''boundary conditions''' and their types which are '''inlet, outlet, top''' and '''bottom'''.
  
 
|-
 
|-
 
| 05:27
 
| 05:27
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| Also this being a '''simple geometry ''' '''mergePatchPair''' and '''edges''' are to be kept '''empty'''.Close the '''blockMeshDict''' file
+
| As this is a 2D Geometry,  '''front and Back''' are kept as '''empty'''.
  
 
|-
 
|-
−
| 05:38
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| 05:35
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| In the '''command terminal''' Type '''cd space ..(dot dot) '''and press enter
+
| Also, this being a simple geometry,  '''mergePatchPair''' and '''edges''' are to be kept '''empty'''. Close the '''blockMeshDict''' file.
  
 
|-
 
|-
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| 05:44
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| 05:46
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| Again 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
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| 05:52
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| Now in the terminal type '''cd '''space '''0 (Zero) and press enter'''Now Type''' ls and press enter'''
+
| Again, type '''cd space .. (dot dot)''' and press '''Enter'''.
  
 
|-
 
|-
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| 05:58
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| 05:57
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| This contains the '''intial boundary conditions ''' and''' wall functions''' for the '''channel case'''
+
| Now. in the terminal, type '''cd space 0 (Zero)''' and press '''Enter'''. Now, type "ls" and press '''Enter'''.
  
 
|-
 
|-
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| 06:05
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| 06:06
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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'''
+
| This contains the '''intial boundary conditions ''' and''' wall functions''' for the '''channel case'''.
−
which the are '''initial conditions of the flow'''
+
  
 
|-
 
|-
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|06:20
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| 06:12
−
|Let me switch back to the slides
+
| 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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| 06:24
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|06:28
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| '''Calculate k''' which is the '''turbulent kinetic energy''' from the '''formula''' given in the slide
+
|Let me switch back to the slides.
  
 
|-
 
|-
−
| 06:29
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| 06:31
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|Where '''Ux, Uy and Uz''' are the '''velocity''' '''components in the x, y and z direction''' And '''U' ( dash ) = 0.05''' times '''u''' actual
+
| Calculate 'k' which is the '''turbulent kinetic energy''' from the formula given in the slide
  
 
|-
 
|-
−
| 06:43
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| 06:37
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| Calculate '''epsilon''' from the '''formula''' given Where '''epsilon''' is the''' rate of disspiation turbulent  energy''' '''C mu''' is a '''constant''' and its value is''' 0.09'''
+
|where Ux, Uy and Uz are the '''velocity''' '''components in the x, y and z directions and''' U' ( dash ) = 0.05''' times '''u''' actual.
  
 
|-
 
|-
−
| 06:56
+
| 06:50
−
|And''' l''' is the '''length of the channel''' Let me minimise this
+
| 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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| 07:02
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| 07:04
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| Change only the '''boundary names''' in each of the above '''folder'''
+
|And 'l' is the length of the '''channel'''. Let me minimize this.
  
 
|-
 
|-
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| 07:07
+
| 07:10
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| Note that the values of '''nut, nuTilda and R ''' are to kept default
+
| Change only the '''boundary names''' in each of the above files.
  
 
|-
 
|-
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|07:13
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| 07:14
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| Rest of the '''files''' should contain initial value for each of the '''boundary faces'''
+
| Note that the values of '''nut, nuTilda, R ''' are kept to default.
  
 
|-
 
|-
 
| 07:21
 
| 07:21
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| Now in the terminal Type '''cd (space) ..(dot dot) and press enter'''
+
| Rest of the files should contain the initial value for each of the '''boundary faces'''.
  
 
|-
 
|-
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| 07:27
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| 07:28
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| There are no change to be done in the '''system folder'''
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| Now, in the terminal, type '''cd (space) ..(dot dot)''' and press '''Enter'''.
  
 
|-
 
|-
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| 07:31
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| 07:35
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|Now We need to '''mesh the geometry''' To do this In the '''command terminal''' '''type blockMesh and press enter'''
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| There are no changes to be done in the '''system''' folder.
  
 
|-
 
|-
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| 07:40
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| 07:39
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|'''Meshing''' is done.Now Let me switch back to the slide
+
|Now we need to '''mesh''' the geometry. To do this, in the command terminal, type "blockMesh" and press '''Enter'''.
  
 
|-
 
|-
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| 07:45
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| 07:48
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| The '''type of solver''' we are using here is '''SimpleFoam'''It is a '''Steady-state''' solver for '''incompressible, turbulent flow'''
+
| The '''Meshing''' is done. Now let me switch back to the '''slide'''.
  
 
|-
 
|-
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| 07:55
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| 07:53
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|let me minimise this
+
| 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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| 07:56
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| 08:02
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| In the '''command terminal''' '''type simpleFoam and Press enter'''
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|Let me minimize this. In the command terminal, type "simpleFoam" and press '''Enter'''.
  
 
|-
 
|-
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| 08:03
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| 08:12
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| '''Iterations running''' will be seen in the '''command terminal'''
+
| '''Iterations''' running will be seen in the command terminal.
  
 
|-
 
|-
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| 08:07
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| 08:15
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| '''Iterations '''running may take some time
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| '''Iterations '''running may take some time.
  
 
|-
 
|-
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| 08:11
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| 08:18
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| The '''iterations''' will stop once the solution is '''converged''' or it reaches its '''end time value'''
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| 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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| 08:24
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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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| 08:20
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| 08:36
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|type '''paraFoam and press enter'''.This will open up the '''paraview window'''
+
| On the left hand side of the '''paraView''' window, click '''Apply'''. The geometry can be seen here.
  
 
|-
 
|-
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| 08:28
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| 08:43
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| On let hand side of the '''paraview''' '''window''' click '''Apply'''.The '''geometry '''can be seen here.
+
| On top of the '''active variable control''' menu, change the drop down menu from '''solid color''' to capital '''U'''.
−
 
+
−
|-
+
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| 08:35
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−
| On top of '''active variable control menu change '''the '''drop down menu''' from '''solid color to capital U'''
+
  
 
|-
 
|-
 
| 08:50
 
| 08:50
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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'''.
  
 
|-
 
|-
−
| 09:00
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| 09:01
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|you can see the final value of the '''velocity magnitude'''
+
|You can see the final value of the '''velocity magnitude'''.
  
 
|-
 
|-
 
| 09:07
 
| 09:07
−
| 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.
  
 
|-
 
|-
−
| 09:16
+
| 09:17
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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.
  
 
|-
 
|-
−
| 09:24
+
| 09:25
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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.
  
 
|-
 
|-
−
| 09:36
+
| 09:37
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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.
  
 
|-
 
|-
−
| 09:46
+
| 09:47
−
|Using '''openfoam''' we obatain a '''velocity of 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.
  
 
|-
 
|-
−
| 09:57
+
| 09:58
−
| 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'''
+
|-
 +
| 10:09
 +
| As an assignment- solve the problem for '''Reynold's Number equal to 1500''' and '''validate''' it with the analytical result.
  
 
|-
 
|-
−
| 10:08
+
| 10:18
−
| As an assignment
+
| Watch the video available at this URL:  http://spoken-tutorial.org/What_is_a_Spoken_Tutorial
−
Solve the problem for '''Reynold Number 1500''' and
+
  
−
'''validate it with the analytical result'''
+
It summarizes the Spoken Tutorial project. If you do not have good bandwidth, you can download and watch it.
  
 
|-
 
|-
−
| 10:17
+
| 10:29
−
| 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.
+
| 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'''
−
| 10:28
+
−
| 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 [mailto:contact@spoken-tutorial.org contact@spoken-tutorial.org]
+
  
 
|-
 
|-
−
| 10:42
+
| 11:05
−
| 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.  
+
| '''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.  
  
 
|-
 
|-
−
| 10:52
+
| 11:15
−
|More information on the same is available at the following URL link http://spoken-tutorial.org/NMEICT-Intro
+
|More information on this mission  is available at the following URL link: http://spoken-tutorial.org/NMEICT-Intro
  
 
|-
 
|-
−
| 10:57
+
| 11:20
−
| This is Rahul Joshi from IIT BOMBAY signing off.Thanks for joining
+
| This is Rahul Joshi from IIT Bombay, signing off. Thanks for joining.
  
 
|}
 
|}

Latest revision as of 15:00, 11 April 2019

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 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.


01:01 As a prerequisite for this tutorial, you should know how to create geometry using OpenFOAM.
01:08 If not, please refer to the relevant tutorials on our website.
01:14 We simulate flow in a channel to determine flow development length along the downstream. Channel flow problem description.
01:24 The boundary names and the inlet conditions are shown as in this figure.
01:31 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.
01:42 Using the formula, the length of the channel comes out to be 5 meters and height is kept as 1 meter.
01:50 The Inlet velocity is 1 meter per second. And, we are solving this for a Reynolds number ( Re ) equal to 100.
01:58 This is a steady state problem . Therefore we are using a steady state incompressible solver for this case.
02:06 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.
02:27 The folder is named as channel. Now, let me switch to the folder.
02:33 Copy 0, Constant and System folders of any other case, in the simpleFoam directory.
02:42 I have copied the file structure of the case pitzDaily.
02:46 Paste it inside the channel folder and make the necessary changes in the geometry, boundary faces and boundary condition.
02:56 Now, let me open the command terminal.
02:59 To do this, press Ctrl+Alt +t keys simultaneously on your keyboard.
03:05 In the terminal, type "run" and press Enter.
03:09 Now type cd space tutorials and press Enter.
03:16 Now type cd space incompressible and press Enter.
03:23 Type cd space simpleFoam and press Enter.
03:28 Now type cd space channel and press Enter.
03:36 Now, type "ls" and press Enter.
03:41 You will see three folders 0, Constant and system.
03:45 Now type cd space constant and press Enter.
03:56 Now type "ls" and press Enter.
04:00 In this, you will see the files containing properties of fluid and a folder named polymesh.
04:07 RASProperties contains Reynolds-averaged stress model.
04:08 transportProperties contains the transport model and kinematic viscosity that is (nu), in this case is set at 0.01 m²/s.
04:25 Now in terminal, type cd space polyMesh and press Enter. Now, type "ls" and press Enter.
04:38 You will see the blockMeshDict file here.
04:42 To open up the blockMeshDict file, in the terminal, type "gedit space blockMeshDict" and press Enter. Scroll down.
04:56 The geometry is in meters. So, the convertTometers is set to 1. Next, we have defined the vertices of the channel.
05:07 We have used a 100 X 100 mesh size here and cell spacing is kept as ( 1 1 1 ).
05:15 Next, we have setup the boundary conditions and their types which are inlet, outlet, top and bottom.
05:27 As this is a 2D Geometry, front and Back are kept as empty.
05:35 Also, this being a simple geometry, mergePatchPair and edges are to be kept empty. Close the blockMeshDict file.
05:46 In the command terminal, type cd space ..(dot dot) and press Enter.
05:52 Again, type cd space .. (dot dot) and press Enter.
05:57 Now. in the terminal, type cd space 0 (Zero) and press Enter. Now, type "ls" and press Enter.
06:06 This contains the intial boundary conditions and wall functions for the channel case.
06:12 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.
06:28 Let me switch back to the slides.
06:31 Calculate 'k' which is the turbulent kinetic energy from the formula given in the slide
06:37 where Ux, Uy and Uz are the velocity components in the x, y and z directions and U' ( dash ) = 0.05 times u actual.
06:50 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.
07:04 And 'l' is the length of the channel. Let me minimize this.
07:10 Change only the boundary names in each of the above files.
07:14 Note that the values of nut, nuTilda, R are kept to default.
07:21 Rest of the files should contain the initial value for each of the boundary faces.
07:28 Now, in the terminal, type cd (space) ..(dot dot) and press Enter.
07:35 There are no changes to be done in the system folder.
07:39 Now we need to mesh the geometry. To do this, in the command terminal, type "blockMesh" and press Enter.
07:48 The Meshing is done. Now let me switch back to the slide.
07:53 The type of solver we are using here is SimpleFoam. It is a Steady-state solver for in-compressible and turbulent flows.
08:02 Let me minimize this. In the command terminal, type "simpleFoam" and press Enter.
08:12 Iterations running will be seen in the command terminal.
08:15 Iterations running may take some time.
08:18 The iterations will stop once the solution is converged or it reaches its end time value.
08:24 To view the results in paraView, in the terminal, type "paraFoam" and press Enter. This will open up the paraView window.
08:36 On the left hand side of the paraView window, click Apply. The geometry can be seen here.
08:43 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.
09:01 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.
09:17 Now go to Display, scroll down. You can see Rescale, click on it.
09:25 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.
09:37 The results obtained can be validated with the analytical solution for laminar flow in achannel which is u(max)=1.5 Uavg.
09:47 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.
09:58 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.
10:09 As an assignment- solve the problem for Reynold's Number equal to 1500 and validate it with the analytical result.
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11:20 This is Rahul Joshi from IIT Bombay, signing off. Thanks for joining.

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