Difference between revisions of "OpenFOAM/C2/Creating-curved-geometry-in-OpenFOAM/English-timed"

| Hello and welcome to the '''spoken tutorial''' on '''Creating Curved geometry in OpenFOAM'''.

| In this tutorial, I will show you:

|* Steps for creating  a curved geometry in openfoam.

|* Viewing the results in '''paraview'''

|To record this tutorial,

|I am using: '''Linux Operating system Ubuntu''' version 10.04, '''OpenFOAM''' version 2.1.0  

|'''ParaView''' version 3.12.0.

|We will create a geometry for flow over a cylinder.

|Note that I am using this case just for explanation.

|The cylinder is in the form of a semi circle.

|The entire geometry is divided into '''block'''s.

|We break the semi circle into equal number of parts.

|Now minimize this.

| Open a 'blockMeshDict' file of the previous tutorial.

|I have already opened it.

|Scroll down. For simple geometries, you can see that  '''edges '''is kept empty.

|  Now Create a new 'blockMeshDict' file.

|To do this, let us minimize this first.

| Now, right-click > '''create document > empty file'''.

| Name this as 'blockMeshDict'.

|Note that M and D here are capital.

|Open this.

| Now you can copy the initial few lines from the 'lid driven cavity' up to 'convertTometers'.

|Go up, copy this up to 'convertToMeters'.

| Copy this and paste it in the new 'blockMeshDict' file.

|Now, change the 'convert to meters' from point one to one.

| As our geometry is in meters, we will keep this as one.

| Now press '''Enter''' ,  press '''Enter''' again.

| After this, you need to enter the co-ordinates of the geometry in vertices.

|Let me switch back to the '''slide'''. Note that the points should be ordered  in such a way starting from 0, 1, 2, 3, 4 and so on, as shown in the figure.

| Minimize the slide. Now, type "vertices" in the 'blockMeshDict' file and press '''Enter'''.

| Insert the open bracket and press '''Enter'''.

|  Now enter the co-ordinates of the geometry as shown in the diagram.

| Let me switch back to the slides.

|  For explanation, I will use right half of the semi-circle.

| Enter the values for the points in the figure starting from 0.

|Let me switch back to the 'blockMeshDict' file.

| Leave some space and enter the co-ordinates of point 0.

|  Open close bracket  enter '''0.5 (space) 0 (space) 0'''. Press '''Enter'''.

| Again leave some space , open close bracket.

|Enter the co-ordinates for point  '''1 (space) 0 (space) 0'''. Press '''Enter'''.

|Now leave two vertical spaces, again  press '''Enter''', again  press '''Enter'''.

| Leave some space and enter the co-ordinates for point number 4.

| Open close bracket, enter '''0.707 (space) 0.707 (space) 0'''

|  Press '''Enter'''. Leave some space.

|Open close bracket.

|  Enter the co-ordinates for the  point 5.

|Enter '''0.353 (space) 0.353 (space) 0''', press '''Enter'''.

| Now, leave 4 vertical spaces and enter co-ordinates for point number 9.

| 1 2 3 4 , again press '''Enter''', leave some space.

|Open, close bracket.

|  Enter '''0 (space) 1 (space) 0''', press '''Enter'''.

|  Leave some space.

|Enter the co-ordinates for point number 10.

|  Open close bracket ''' 0 (space) 0.5 (space) 0''' press '''Enter'''.

|Insert a close bracket  put a semi-colon and press '''Enter'''.

|Again press '''Enter'''.

| Now, type "blocks", press '''Enter'''.

|Insert an open bracket, press '''Enter'''.

| The '''block numbers''' are circled as shown in the figure.

|Now let me switch back to the 'blockMeshDict file'.

| Leave some space.

|Now enter the type of  the '''block''' i.e. '''Hex''', leave some space.

|  Now enter the points for the blocks.

| Open, close brackets.

|Leave some space, the '''simple Grading''' can be kept as '''(1 1 1) ''' and press '''Enter'''.

| For creating the '''blocks''', please refer to the tutorial on '''creating simple geometry in OpenFOAM'''.

|Note that there will be more number of '''blocks''' in this example.

|Now, insert a close bracket.

|Insert a semi-colon, and  press '''Enter'''. Again press '''Enter'''.

| In the next line, type "edges" and press '''Enter'''.

|Insert a open bracket and press '''Enter'''.

|  Here you need to enter the points which are the end points of the arcs.

|Leave some space and type "arc". Leave some space, type the points which are the end points of the arc.

|Let me switch back to the slide. Now, insert the  end points of the arc

|In this figure, we start with arc '''0 5'''.

|Let me switch back to the 'blockMeshDict file'.

|Enter ''' 0 space 5'''.

| Leave some space. Insert open, close bracket.

| In  the bracket, enter the co-ordinates of any intermediate point in between the two arc points.

|Now, let me switch back again to slides.

| In the figure, you can see that you have to pick up a point  in between the two end  points of the arc.

|In this geometry, I have picked up right half of the circle.

| Using simple geometric relations, you can find the co-ordinates of the intermediate points as shown in the semi-circle.

| Similarly you can repeat the procedure for rest of the semi-circle geometry.

|Now, let me switch back to the 'blockMeshDict file'.

| Press '''Enter'''.

| Note that there are more number of arcs in this example.

| Insert a close bracket.

|Insert a semi -colon, press '''Enter''', again press '''Enter'''.

| Now enter the '''boundary patche'''s after arcs.

|Refer to the tutorial on '''Simple geometry in OpenFOAM''', for entering the '''boundary patches'''.

| Enter "boundary", press '''Enter'''.

|Insert open bracket  press '''Enter'''. Insert close bracket  semi-colon, press '''Enter'''.

|Again press '''Enter'''.

| Now, in the next line, type "mergePatchPairs".

|Note that 'P' here is capital.

|  Press '''Enter'''.

|Insert a open bracket,  press '''Enter'''.

| Since there are no '''patches''' to be merged, this can be kept empty.

|Insert a close bracket.

|Insert a semi colon and press '''Enter'''.

|Let me switch back to the slides.

|Similarly, enter the co-ordinate points for the points in the front face of unit thickness of the geometry as shown in the figure.

| Now, open a '''Command terminal'''.

| In the '''command terminal''', type the '''path''' for your case.

| I have already set the '''path''' for the tutorial case of '''flow over cylinder'''.

|  In the '''terminal''', type "blockMesh" for '''meshing''' the geometry and press '''Enter'''.

|'''Meshing''' is done.

|Now, type "paraFoam" in the '''terminal'''  and press  '''Enter''' to view the geometry.

| Let me drag this to the capture area.

| Now on  left-hand side of '''object inspector menu''', click '''Apply'''.

|  Geometry will be created as seen in the '''paraview''' window.

| Scroll down the '''Object inspector menu'''.

|  Check or uncheck the '''Mesh''' field box.

|You can also see the''' wire frame '''of the geometry.

|On top of  the '''active variable control menu''',  in the drop down menu, change from '''Surface''' to '''wireframe'''.

| You can see the '''wireframe model''' of the geometry.

|Close this. Let me switch back to the slides.

| In this tutorial, we learnt:

|* How to create a curved geometry.

|* How to enter points for edges in '''OpenFOAM'''.

|This brings us to the end of the tutorial.

| As an Assignment-

|Create a geometry with inner semi-circle of radius 2 meters and outer semi- circle of radius 4 meters  and view the geometry in '''paraview'''.

| 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.com'''

|'''Spoken Tutorials''' are part of '''Talk to a Teacher''' project.

|More information on this mission is available at this  link:

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

|  This is Rahul Joshi from '''IIT Bombay''', signing off. Thanks for joining