View source for OpenFOAM/C3/Simulating-Hagen-Poiseuille-flow/English-timed

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|'''Time'''
|'''Narration'''

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|00:02
| Hello and welcome to the '''spoken tutorial''' on '''Simulating Hagen-Poiseuille flow''' in '''OpenFOAM'''.

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| 00:09
| In this tutorial, we will see:
To create and '''mesh 3D cylindrical pipe'''
To '''simulate '''the '''Hagen-Poiseuille flow''' having''' fixed pressure ratio''' across '''boundaries''' and  
To visualize the '''velocity contour '''in '''ParaView'''.

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| 00:25
| To record this tutorial, I am using: 
'''Linux Operating system Ubuntu '''12.04 
'''OpenFOAM''' version 2.1.1  and 
'''ParaView''' version 3.12.0 

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| 00:38
| 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.

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| 00:43
| To practice this tutorial, learner should have the knowledge of basic '''Fluid Dynamics''' and '''Hagen-Poiseuille flow'''

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| 00:51
| Here is, '''Hagen-Poiseuille Flow''' diagram. We can see the dimensions and boundaries of the pipe.

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| 00:57
|'''Viscosity''' of  the fluid used, that is, water is given. Pressure at the '''inlet''' is 20''' Pascals''' and at the '''outlet''' is 0''' Pascals.'''

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| 01:09
|As it is an '''in compressible flow''', only the pressure difference is of importance.

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| 01:15
| Formulas and Analytical Solution:
For '''Hagen-Poiseuille flow,''' '''Pressure drop''' along the pipe is: '''P1 minus P2 equals 32 mew U average L upon D square'''.

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| 01:30
|By substituting the values from the previous diagram, we get '''U average equals to 0.208 meters per second'''. '''Maximum Velocity''' is given as: two times the '''average velocity''' which would be 0.416 meters per second'''.

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| 01:49
|'''Reynolds Number''' for the flow is: '''U average into D upon nu''', that comes out to be 2080. Hence, the flow is '''transient'''.

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| 01:61
| Type of '''solver''' used here is '''IcoFOAM'''.

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| 02:06
|It is a '''Transient Solver'''. It is used for '''in-compressible, laminar flow''' of Newtonian fluids.

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| 02:13
| '''Pressure Boundary Conditions '''used-
at '''Inlet: fixed Pressure'''
at '''Outlet: fixed Pressure'''
at '''Walls: Zero Gradient'''.

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|02:24
| '''Velocity Boundary Conditions''' used -
at '''Inlet: pressure Inlet Velocity''' 
at '''Outlet: zero Gradient''' 
at '''Walls: fixed Value'''.

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| 02:33
| For executing this case- first, let's create the '''case directory''' in the ''''icoFoam'''' folder and give it some name. I have named it as '3dpipe'.

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| 02:46
| To know the location of this folder, go through the tutorial on '''Lid driven cavity'''. Copy this '0' (zero), 'constant' and 'system' folders of '''lid driven cavity''' problem in the newly created folder.

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| 02:59
| Let's go inside the '3dpipe' folder.

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| 02:63
| I have already copied the folders into my '''3dpipe''' folder and modified the files in it.

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| 03:10
| Now, let's go into the '0' folder and open the 'P' file. This is the''' pressure boundary condition''' file.

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| 03:19
| Note that the dimensions are in '''meter square per second square (m2/s2)'''.

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| 03:25
| Hence the pressure value in '''pascals''' is divided by the density, that is, 1000 Kg/m3 (Kg per meter cube)''' and written here. 

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| 03:34
| Let's close the file.

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| 03:37
| File containing the '''velocity boundary conditions '''is as seen. Let's open the file. We can see the '''velocity boundary conditions''' for '''inlet, outlet''' and '''fixed walls'''. 

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| 03:48
| Let's close the file and come out of the '0' folder.

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| 03:53
| To see the '''blocking''' strategy, let me switch back to the '''slide'''s.

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| 03:59
| To create a '''3D''' geometry of a pipe, I have made a '''2D''' circular '''geometry '''and extruded the length in z-direction.

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| 04:08
| Numbering pattern is as shown. You can also see the dimensions of the mesh.

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| 04:16
| To see the '''blockMeshDict''' file, let's minimize the slides. 

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| 04:21
| Let's go into the folder 'constant', and then 'polyMesh'. Let's open the 'blockMeshDict' file. You can see the '''vertices, logs, edges''' and '''boundaries''' for inlet, outlet and '''fixed wall'''.

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| 04:42
| Let's close the file and let's come out of the '''polyMesh''' folder.

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| 04:47
| We see the 'transportProperties' file. Let's open the file. Note the '''dynamic viscosity '''value, here, is 1 e-06.

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| 04:58
| Let's close the file and come out of the 'folder 'constant'.

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| 04:64
| Let's go into the 'system' folder. Now, let's have a look at the 'controlDict' file. 

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| 05:12
| The solution '''converges''' after 18 seconds. Therefore, the final '''time step''' is kept 19. The '''time step''' has been set to 1e-03.

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| 05:25
| Let's close the file. Let's close the 'Home' folder.

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| 05:31
| Now to '''execute''' the case, we will first go inside the '3dpipe' folder through terminal. Let's open the terminal by pressing '''control, alt '''and '''t''' keys, altogether.

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| 05:45
| Type "run" and press '''Enter'''.

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| 05:49
| Type '''cd (space) tutorials''' and press '''Enter'''.

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| 05:55
| Type '''cd (space) incompressible''' and press '''Enter'''.

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| 05:60
| Type '''cd (space) icoFoam '''and press '''Enter'''.

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| 05:64
| Type '''cd (space) 3Dpipe '''and press '''Enter'''.

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| 06:10
| Now to create the '''mesh''', type "blockMesh" and press '''Enter'''. '''Meshing''' has been done.

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| 06:21
| To start the '''iterations''', type "icoFoam" and press '''Enter'''. We  see the '''iterations''' are  running.

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| 06:32
| Iterations have been done. After the iterations end, type "paraFoam" for '''postprocessing''' the results and press '''Enter'''. It will open the" paraview". This is " paraview".
 
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| 06:46
| Let's click on '''Apply''' on the left hand side of the '''Object inspector''' menu to see the''' geometry.'''

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| 06:54
| Let's rotate the geometry for a better view.

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| 06:57
| Click on the '''active variable control''' menu and select '''U''' in the drop-down menu.

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| 07:06
| At the top, in '''VCR toolbar''', click on '''Play''' button.

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| 07:11
| Go to '''Object Inspector''' menu, go to '''Display''', click on '''Rescale to data range.'''

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| 07:21
| To view the half section, go to the toolbar named '''common''', click on '''Clips''', go to '''object inspector''' menu > '''properties''' and press '''Apply'''. Let's Zoom in.

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| 07:40
| Let's open the '''color legend.'''

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| 07:43
| We can see the maximum velocity is near to the actual maximum velocity i.e 0.4 meters per second.

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| 07:51
| To view the graph, go to '''Filters'''at the top > '''Data Analysis''' and press '''Plot Over Line.'''

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| 08:01
|Press '''Y Axis''' and press '''Apply'''.

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| 08:05
| We can see the parabolic profile for '''Hagen-Poiseuille flow'''.

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| 08:10
| Let's close the graph. Let's close '''ParaView''' and switch to the''' slides'''.

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| 08:17
| In this tutorial, we have learned:
To create and '''mesh''' a '''3D pipe geometry'''.
To simulate '''Hagen-Poiseuille flow''' for a fixed pressure ratio across boundaries and
To visualize the velocity results in '''Parafoam '''

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| 08:35
| As an assignment-
Change the '''geometry parameters '''such as length and diameter.
Change the corresponding pressure ratio and use the fluid of different '''viscosity.'''

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| 08:52
| Watch the video available at the following link.  It summarizes the Spoken Tutorial project. If you do not have good bandwidth, you can download and watch it. 

|-
| 08:59
| The Spoken Tutorial Project team:  * Conducts workshops using spoken tutorials.  
Gives certificates for those who pass an online test.  
For more details, please write to: '''contact at spoken hyphen tutorial dot org''' 

|-
| 09:35
| '''Spoken Tutorial''' project is a part of the '''Talk to a Teacher''' project.  It is supported by the National Mission on Education through ICT, MHRD, Government of India.  More information on this mission is available at:
'''spoken hyphen tutorial dot org slash NMEICT hyphen Intro''' 
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