OpenFOAM/C2/Creating-curved-geometry-in-OpenFOAM/English

Tutorial: Creating curved geometry in OpenFOAM.

Script and Narration: Rahul Joshi

Keywords: Video tutorial, CFD, Flow over cylinder, edges, blocks.

Visual Cue	Narration
Slide 1	Hello and welcome to the spoken tutorial on creating Curved geometry in OpenFOAM
Slide 2 : Learning Objectives	In this tutorial I will show you Steps for creating a create a curved geometry in openfoam Viewing the results in paraview
Slide 3: System Requirement	To record this tutorial I am using Linux Operating system Ubuntu version 10.04. OpenFOAM version 2.1.0 ParaView version 3.12.0
Slide 4: Hover over cylinder Hover over the geometry Hover over blocks break the circle into 4 parts	We will create a geometry for flow over cylinder. Note that I am using this case just for explanation. The cylinder is in a form of a semi circle. Meshing is a body fitted grid. The entire geometry is divided into blocks. We break the semi circle into equal number of parts. Now minimise this
Open the lid driven cavity blockMeshDict file Hover over arcs	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 minimise this first
On the desktop Right click > create document >create file	Now Right click > create document > empty file
Name this as blockMeshDict	name this as blockMeshDict. Note that M and D here are capital Open this
Copy the blockMeshDict of Lid driven cavity file from line 0 to line convert to meters	Now you can copy the initial few lines from the lid driven cavity upto convertTometers
Copy these lines	Go up copy this upto convertToMeters
Paste in the new blockMeshDict file	Copy this and paste it in the new blockMeshDict file
Change the geometry to point one to one	Change the convert to meters from point one to one
Geometry is in meters	As our geometry is in meters we will keep this as one
Press enter	Now press enter , press enter again
Refer to the figure of flow over cylinder in slide 4	After this you need to enter the co-ordinates of the geometry in vertices Note that the points should be in an ordered way starting from 0,1,2,3 etc. as shown in the figure
Type vertices after convertTometers	Now type vertices in the blockMeshDict file and press enter
	Insert a open bracket Press enter
Enter the co-ordinates as shown in the diagram	Now enter the co-ordinates of points as shown in the diagram.
	Let me switch back to the slides
Refer to the next slide for half semi-circle	For explanation I will use the right half of the semi-circle
current blockMeshDict file	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 co-ordinates of point 0
Point 0 - Insert (0.5 0 0)	Open close bracket and enter (0.5 (space) 0 (space) 0)
	Again leave some space , open close bracket
Point 1- Insert (1 0 0)	Enter co-ordinates for point 1 (1 (space) 0 (space) 0) Press enter
	leave two vertical spaces , press enter again press enter
	leave some space and enter co-ordinate for the point number 4
Point 4 – Insert (0.707 0.707 0)	Open close bracket, enter (0.707 (space) 0.707 (space) 0)
	Press enter Leave some space Open close bracket
Point 5 -Insert (0.353 0.353 0)	Enter the co-ordinates for 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
Vertical spaces	1 2 3 4 , again press enter leave some space Open close bracket
Point 9 – Insert (0 1 0)	Enter (0 (space) 1 (space) 0), press enter
	Leave some space Enter co-ordinates for point number 10
Point 10 -Insert (0 0.5 0)	Open close bracket (0 (space) 0.5 (space) 0) and press enter
Remaining part of the semi-circle use the same procedure	Similarly enter the co-ordinates for remaining points in the geometry. Insert a close bracket and put a semi-colon Press enter Again press enter
In blockMeshDict file type blocks	Now Type blocks and press enter Insert a open bracket and press enter
	Let me switch back to the slides
Slide showing blocks	Block numbers are circled as shown in the figure
	Now let me switch back to the blockMeshDict file
Enter the type of block here	Leave some space Enter the type of block i.e. Hex leave some space
Enter points for blocks	Now enter the points for the blocks Open close brackets Leave some space
SimpleGrading (1 1 1)	ths simple grading can be kept as (1 1 1) press enter
Refer to the previous tutorial on simple geometry in openfoam	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
Insert close bracket and semi-colon	Insert a close bracket Insert a semi-colon and press enter Again press enter
Type edges	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
Enter the arc points	Leave some space and type arc and leave some space Type the points which are the end points of the arc
Insert end points of the arc From ths slide	In this insert the end points of the arc We start with 0 5 Let me switch back to the blockMeshDict file Enter 0 space 5
	Leave some space Insert open close bracket
	In brackets enter the co-ordinate of any intermediate point in between the two arc points. Now Let me switch back again to slides
Slide: for arcs	In the figure you can see that you have to pick up a point in between the two points.
	In this geometry I have picked up right half of the circle
Slide shwoing trignometric relations Sin(theta) and cos(theta) relations	Using simple geometric relations you can find the co-ordinates of the intermediate point shown in the semi-circle
Repeat the above procedure for the remaining semi-circle	Similarly you can repeat the procedure for rest of the semi-circle geometry
	Now let me switch back to the blockMeshDict file Now press enter
	Note that there are more number of arcs in this example
	Insert a close bracket Insert a semi -colon and press enter again press enter
In the next line after arcs refer to the tutorial on creating simple geometry in openfoam	Enter the boundary patches after arcs Refer to the tutorial on Simple geometry in OpenFOAM For entering the boundary patches
Enter boundary	Enter boundary Insert open-close bracket and press enter Again press enter
Type mergePatchPairs P here is capital	In the next line type mergePatchPairs Note that P here is capital
	Press enter Insert a open bracket and 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
Slide : Points for the front face in the geometry	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
Press Ctrl+Alt+t keys	Open a Command terminal
Type run and press enter cd tutorials and press enter cd basic and press enter cd potentialFoam and press enter cd cylinder and press enter	In the command terminal type the path for your case file
	I have already set the path for the tutorial case of flow over cylinder
Type blockMesh and press enter	In the terminal type blockMesh for meshing the geometry and press enter Meshing is done
Type paraFoam and press enter	Now Type paraFoam in the terminal and press enter to view the geometry
	Let me drag this to the capture area
In the object inspector menu click APPLY button	Now on the left side of object inspector menu click Apply The geometry created will be seen in the paraview window
	Scroll down the Object inspector menu
Check and uncheck the mesh field box	Check and uncheck the Mesh field box
Demo	You can see different regions of the geometry. You can also see the wire frame of the geometry
For wireframe of the geometry Change from surface to wireframe	On top of 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
Slide	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
Slide	As an Assignment Create a geometry with inner semi-circle of radius 2 meters and outer circle of radius 4 meters and View the results in paraview
Slide 8: About Spoken tutorials	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.
Slide 9: About Spoken tutorials	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
Slide 10: Acknowledgement	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. More information on the same is available at the following URL link http://spoken-tutorial.org/NMEICT-Intro
About the contributor	This is Rahul Joshi from IIT BOMBAY signing off. Thanks for joining

Contributors and Content Editors

Chandrika, DeepaVedartham, Nancyvarkey, Rahuljoshi