Difference between revisions of "Contrib icoStructFoam"

Latest revision as of 12:19, 29 August 2015

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1 Description

This solver is a hybrid of icoFoam and stressedFoam. One grid-region is an incompressible fluid, the other is a solid. The pressure of the fluid is used to deform the solid.

This solver is only a demo. It should not be used to simulate the real world

Ah. And by the way: it does not work in parallel

2 Algorithm

At each time-step the following things are done:

1. the equations in the fluid region are solved
2. fluid pressures at the fluid/solid-interface are written as boundary equations to the solid
3. the equations for the solid are solved
4. displacements for the interface-nodes of the solid region are written to the interface-nodes of the fluid region
5. the grid of the fluid region is deformed

3 Usage

Due to the two grids the standard Utilities for pre- and post-processing (FoamX and paraFoam) can't be used. Everything is setup with the help of a text-editor.

In order for blockMesh to work on the grid regions you've got to fool it:

ln -s region1/polyMesh/ icoStructFoamTest/constant/polyMesh
blockMesh . icoStructFoamTest
rm icoStructFoamTest/constant/polyMesh
ln -s region2/polyMesh/ icoStructFoamTest/constant/polyMesh
blockMesh . icoStructFoamTest
rm icoStructFoamTest/constant/polyMesh

To write the data of the two regions for ParaView just use foamToVTK:

foamToVTK . icoStructFoamTest -mesh region1
foamToVTK . icoStructFoamTest -mesh region2

An alternative approach is described in How to postprocess multiple regions.

The fluid mesh is deformed. The solid mesh has to be deformed while post-processing (with the Warp (vector) filter)

4 Example cases

Please note that none of these cases resembles anything from the real world and only server for demonstration purposes

4.1 Deformable channel

Pressure and strain

Velocity and strain

This case simulates flow in a channel. One wall of the channel is coupled to a deformable solid.

The two regions are:

• Lower Region: channel with velocity inlet on the left and pressure outlet on the right

• Upper Region: solid which is fixed at the top and free at the left and the right

In the beginning both of them are of equal size and square.

Due to the higher pressure at the inlet the solid gets deformed.

Both pictures are from the end of the simulation. For the solid the strain is shown. For the fluid the left picture the colors show the pressure, the right picture shows the velocity.

4.2 Soft thing on a stick

The two regions

Pressure and strain

This case simulates the flow through a channel with an obstacle that consists of two parts: a solid, fixed part around which a deformable material is wrapped.

The two regions are shown in the picture on the left:

• Blue: the fluid. On the left-side a velocity inlet, on the right side a pressure outlet. Top is a wall, botto, a symmetry boundary.
• Red: the solid. The bottom edges are symmetry boundaries. The inner edges are fixed (the stick in the title)

The picture on the left is the undeformed geometry at the beginning. The picture on the right is the geometry at the end of the simulation. The solid is colored with the strain, the fluid with the pressure.

In certain parts of Austria this is also known as the Lentos-case.

5 Download

5.1 OpenFOAM 1.3

These files are meant to be used with :

• The solver
• Case of the deformable channel
• Case of the soft thing on a stick

5.2 OpenFOAM 1.5-dev

It's available at the following SVN repository folder: trunk/Breeder_1.5/solvers/other/IcoStructFoam @ sourceforge.net/openfoam-extend

Instructions on how to use it are given in the README file.

• Download can be done by using SVN:

  svn checkout svn://svn.code.sf.net/p/openfoam-extend/svn/trunk/Breeder_1.5/solvers/other/IcoStructFoam IcoStructFoam

• Download using Git from the Unofficial-Extend-Project-Mirror:

  git clone https://github.com/Unofficial-Extend-Project-Mirror/openfoam-extend-Breeder1.5-solvers-other-IcoStructFoam.git IcoStructFoam

5.3 OpenFOAM 2.3

This port occurred as a request made here: icoStructFoam on OF-1.6ext

The source SVN repository code was gotten through the unofficial Git mirror indicated in the previous subsection and the port is made available in the branch of23 on this repository: IcoStructFoam repository in wyldckat@github

To download using Git from that repository, run:

git clone https://github.com/wyldckat/IcoStructFoam.git IcoStructFoam
cd IcoStructFoam
git checkout of23

Notes:

• In order to be able to see the deformation on the mesh for the solid region, you need to use the filter "Warp By Vector" in ParaView.
• And you can see each region in location by running:

    paraFoam -region region2 -touch
  paraFoam -region region1

  Then open the file for the second region in the now open ParaView window. For example, the file for the second region in the example case "thingOnStick" is named thingOnStick{region2}.OpenFOAM.

6 History

• 11 Nov 2005: Initial upload
• 10 Nov 2006: Changed Version for 1.3
• 7 Oct 2008: Added version for 1.5-dev, but only on the SVN repository
• 11 Oct 2014: Added instructions for getting version for 1.5-dev from the SVN repository and unofficial Git mirror
• 2 Jan 2015: Added instructions for OpenFOAM 2.3