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-   -   How to simulate problems with rotating motion (http://www.cfd-online.com/Forums/openfoam/90932-how-simulate-problems-rotating-motion.html)

feiqunali July 25, 2011 14:39

How to simulate problems with rotating motion
 
Hello, I am now trying to simulate flapping wing with pitching motion, which need an unsteady solver that can simulate rotating problems. Which solver should I choose and can anybody provide some related case?Thanks a lot!

SD@TUB July 26, 2011 05:31

Hi,

Can you be more precisely about your problem, where you need the rotating motion? I would guess, that you need automatic mesh motion for the rigid flapping wing.
Since you expect moderate motions of your wing than mesh morphing might be an appropriate set-up. There is a simulation of a flapping airfoil with OpenFOAM. Unfortunately, i haven't got the web link right now. Maybe, you will take a look into the OF workshops.
As you mentioned "rotating motion" which is either provided by GGI implementation in 1.6-ext or as a solid body motion called rotatingMotion in 2.0.x! You will find it within src/dynamicFvMesh/* directory of your preferred OpenFOAM version.

/Stefan

elvis July 26, 2011 09:45

Hello,

you are probably interested on the PHD thesis of Frank Bos.

Numerical simulations of flapping foil and wing aerodynamics, mesh deformation using radial basis functions (RBF).
This research is direct applicable to Micro Air Vehicle design and in Wind Turbines.

The RBF is now part of OpenFoam-extent former OpenFOAM-1.5-dev version
=>http://www.cfd-online.com/Forums/ope...on-solver.html

You can find the PHD-Thesis online http://repository.tudelft.nl/assets/...daa1b2/bos.pdf (size 11MB)

The other interesting things might be based on the PHD-thesis of "Sandeep Menon"
Adaptive Tetrahedral Re-Meshing for Deforming Domains,
http://www.openfoamworkshop.org/6th_...ney_slides.pdf

feiqunali July 26, 2011 14:50

The rotating motion is defined by a=a0*sin(2*pi*f*t),a is the angle of attack. Do you mean that I could not simulate such motion in OF1.7.0? By the way, I thought I should use pimpleDyFoam, but I dit not know how to set the boundary condition.

feiqunali July 26, 2011 14:51

Quote:

Originally Posted by SD@TUB (Post 317510)
Hi,

Can you be more precisely about your problem, where you need the rotating motion? I would guess, that you need automatic mesh motion for the rigid flapping wing.
Since you expect moderate motions of your wing than mesh morphing might be an appropriate set-up. There is a simulation of a flapping airfoil with OpenFOAM. Unfortunately, i haven't got the web link right now. Maybe, you will take a look into the OF workshops.
As you mentioned "rotating motion" which is either provided by GGI implementation in 1.6-ext or as a solid body motion called rotatingMotion in 2.0.x! You will find it within src/dynamicFvMesh/* directory of your preferred OpenFOAM version.

/Stefan

The rotating motion is defined by a=a0*sin(2*pi*f*t),a is the angle of attack. Do you mean that I could not simulate such motion in OF1.7.0? By the way, I thought I should use pimpleDyFoam, but I dit not know how to set the boundary condition.

feiqunali July 26, 2011 15:01

Quote:

Originally Posted by elvis (Post 317539)
Hello,

you are probably interested on the PHD thesis of Frank Bos.

Numerical simulations of flapping foil and wing aerodynamics, mesh deformation using radial basis functions (RBF).
This research is direct applicable to Micro Air Vehicle design and in Wind Turbines.

The RBF is now part of OpenFoam-extent former OpenFOAM-1.5-dev version
=>http://www.cfd-online.com/Forums/ope...on-solver.html

You can find the PHD-Thesis online http://repository.tudelft.nl/assets/...daa1b2/bos.pdf (size 11MB)

The other interesting things might be based on the PHD-thesis of "Sandeep Menon"
Adaptive Tetrahedral Re-Meshing for Deforming Domains,
http://www.openfoamworkshop.org/6th_...ney_slides.pdf

Thank you! I have read part of Frank Bos's thesis. It is very helpful. However, as mentioned above, I do not know how to set the boundary conditions, there seems no such boundary condition provided in OF to describe such motion.

SD@TUB July 26, 2011 17:53

Quote:

Originally Posted by feiqunali (Post 317585)
The rotating motion is defined by a=a0*sin(2*pi*f*t),a is the angle of attack. Do you mean that I could not simulate such motion in OF1.7.0? By the way, I thought I should use pimpleDyFoam, but I dit not know how to set the boundary condition.

So you are looking for a prescribed (sinusoidal) mesh motion functionality, contrary to my guess. Depending on your desired motion amplitudes you have to decide, if mesh morphing techniques will not cause much distortion. In doubt you can perform topological mesh changes with GGI.
I am not sure, but i think RBF and GGI indeed are exclusively implemented in 1.6-ext! May someone else could give you more details.
What about the derived boundary conditions like movingWallVelocity, rotatingWallVelocity, etc. May there is one appropriate bc for harmonic oscillation as well.

feiqunali July 26, 2011 21:45

Quote:

Originally Posted by SD@TUB (Post 317606)
So you are looking for a prescribed (sinusoidal) mesh motion functionality, contrary to my guess. Depending on your desired motion amplitudes you have to decide, if mesh morphing techniques will not cause much distortion. In doubt you can perform topological mesh changes with GGI.
I am not sure, but i think RBF and GGI indeed are exclusively implemented in 1.6-ext! May someone else could give you more details.
What about the derived boundary conditions like movingWallVelocity, rotatingWallVelocity, etc. May there is one appropriate bc for harmonic oscillation as well.

Thank you! Maybe I have to install a version of 1.6-ext..

elvis July 27, 2011 04:27

Hi,
you need OpenFOAM-1.6-ext
https://openfoam-extend.svn.sourcefo...nd/trunk/Core/OpenFOAM-1.6-ext/src/dynamicMesh/meshMotion/ =>RBF

to get your Hands on RBF i would advise you to take the LIVE DVD of the EXTEND version from the openfoam workshop
download from http://rcc.its.psu.edu/ofw6/ofw6_v8.iso
in the tutorials the is some not very sophisticated stuff on RBF but boundary conditions etc. are set there

davesmith_01 July 29, 2011 16:08

flapping wing openfoam
 
Hi Guys

Does anyone have any tutorials or cases setup which involve a flapping wing in a moving mesh?

I want to model this but am having a difficult time with boundary conditions and am not sure where they need to be implemented and how the should be implemented for a simple sinusoidal motion (theta=A*sin(2*pi*f*t)).

Also I understand that RBF can be used for this but can openfoam do this in version 1.7 aswell using a different method? I want to use an unstructured grid.

Thanks in advance

Dave

sanjay August 12, 2011 15:55

is it possible to do flapping simulation using STARCCM+ CFD code???
:rolleyes:


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