Computer exercise 1

MVK150: Applied CFD

Aurélia VallierHolger Grosshans

How to get OpenFOAM

Unix/Linux

www.opencfd.co.uk

MS Windows (used in this lab)

http://sourceforge.net/projects/openfoam-mswin/

DOCUMENTATION (linux version)http://foam.sourceforge.net/doc/Guides-a4/UserGuide.pdf

http://www.opencfd.co.uk/http://sourceforge.net/projects/openfoam-mswin/http://sourceforge.net/projects/openfoam-mswin/http://sourceforge.net/projects/openfoam-mswin/

Tree structure

Tree structure

• OpenFOAM is a C++ library of applications

Tree structure

Tree structure

Input files for solving equationse.g. discretization schemes, used solver, timestep, …

Input files for the physical properties-> blockMeshDict = Input file for creating the meshFiles which define the mesh. Created by blockMeshDict

Initial conditions input files in 0. Results created in other folders

The cavity case

• Create a folder CFD_labOF in your local directory

• Copy the cavity case

C:\win32app\cfd\OpenFOAM-1.5\tutorials\icoFoam\cavity

in this folder.

• Open OpenFOAM Designer and do File -> OpenCase to open your cavity case

OpenFOAM Designer

Input files for the caseEditor for the input files

OpenFOAM applications

Create the Mesh

• Look into the constant/polyMesh folder

• Do MeshUtilities -> Generation -> blockMesh -> start

• Look into the constant/polyMesh folder to see that the mesh was created

Look at the mesh in Paraview

• Create an empty file cavity/cavity.OpenFOAM in OpenFOAM Designer (File-> New)

• Open paraview

• Add the pluggins as instructed

• File -> Open and open the file cavity.OpenFOAM

Look at the mesh in Paraview

blockMeshDict

Coordinates of the vertices 0 to 7

Connect the verticesinto one block

The cells are hexagonal

Number of cells in directionx, y and z

The mesh is equidistantin each direction

Name of the boundaries(user defined)

Type of the boundaries- empty type for 2D case- wall type for a wall- patch type for the others.

Connect the verticesinto one patch

• Edit ’constant/polyMesh/blockMeshDict’ in OpenFOAM Designer

Scale

New case : bend pipe

• Copy case ’cavity’ to new case ’pipe’

• Open case ’pipe’ in OpenFOAM Designer

• Edit ’constant/polyMesh/blockMeshDict’

block0

block2

block1

v0

Plan z=0

Plan z=0.1

v1

v2

v7

v5

v3

v4

v6

v13

v15v14

v12

v11

v8

v10

v9

3 m(40 cells)

3 m (40 cells)

1 m

New case : bend pipe

inletvelocity Ux = 1m/s Pressure : zeroGradient

Outlet velocity: zeroGradientPressure: fixedValue

innerWallvelocity : 0pressure : zeroGradient

outerWallvelocity : 0pressure : zeroGradient

blockMeshDict: curved edges

New case : bend pipe

• Create the mesh with BlockMesh

• Create an empty file pipe/pipe.OpenFOAM in OpenFOAM Designer (File-> New)

• Check the mesh in ParaView

• Do not close paraview and go back to the OpenFOAM Designer window

• Define the initial and boundary conditions by editing 0/U and 0/p

• Run icoFoam : solver -> incompressible -> icoFoam

• Check the results in paraView : load the new time steps by clicking the box ’updateGUI’ and ’Apply’.

Check the results in paraview

Load the internal meshand the boundaries

Load velocity and pressure

Show the last time step computed

Show the velocity field

Show the scale

Check the results in paraviewCreate a slice view (Znormal, uncheck ’Show Plane’ and Apply)

Check the results in paraviewSample the results over a line : - Highlight the file ’pipe.OpenFOAM’-Filters -> Alphabetical -> Plot over Line-Define the sampling line-Apply

Check the results in paraview

Try with another sampling line