[ysh1227]

Hi, everyone.
I am new in OF and I study and simulate OF for two month. (OF 2.1.0)

I want to run the Small Horiziontal Axis Wind Tubine case including tower, so I chose pimpleDyMFoam as solver and kOmegaSST as turbulence model.

First, I ran the case without a tower to know the proper condition to simulate, but the result always diverged, increasing Courant Number and other things.

I decided to change the solver to MRFSimpleFoam. But I met the trouble that time step continuity error increase with the iterations.

I tried to find the reason and found that, in this forum, some people had the similar problem.
They had 0 value as AMI: patch source weights min, but I had about 0.1 value
Their solution is to adjust and improve the mesh.
So I adjusted the meshes(AMI) that had the odd values, but the results also became wrong and time step continuity error increase with time.

AMI: Patch source weights min/max/average = 0.679762, 1, 0.998602
AMI: Patch target weights min/max/average = 0.154367, 1, 0.998088

Before I adjusted the mesh, I tried a lot of things to solve the problem.
For example, I had changed fvScheme, fvSolution, time step, decomposePar method, initial condition, Patch type ..........
All of those are useless.

I have studies OF alone and there are no one who can know OF well.

Is there anyone who can advise me about simulation of wind turbine with OF?
AND I want to know the exact meaning of time step continuity error and AMI weight.

[linnemann]

Hi

You can use this as an example.

http://dl.dropbox.com/u/15968063/3DStruct.TSR1.0.tar.gz

That is a 3bladed VAWT with a NACA0012 profile.

Its done using 1.6-ext but you can change the GGI to AMI and it should work with 2.1. Also I was using transientSimpleDyMFoam and not pimpleDyMFoam.

Also you can't use MRF for a VAWT. When the MRF zone is perpendicular to the flow is generates flow that looks like flow over a cylinder. I cant go into the specifics about this other than tell you that it wont work. The same problem exists in Fluent.

[ysh1227]

Thanks, Linnemann.
I will check the example of VAWT right now.

hum..I have another question.
Do you know the specific means about AMI weights and time step continuity error?

[linnemann]

The best thing you could was to upload the case as I've done with the VAWT case and have people have a look at the mesh/setup.

The continuity issues is often related to the mesh and fvSchemes/fvSolutions and BC's so in general it can be anything so it can be a hard one to track down with the little info you have given.

Following this guide will most likely get you more help.

http://www.cfd-online.com/Forums/ope...-get-help.html

[ysh1227]

Thank you
This is the first time to question on the web, so I'm sorry that I didn't give you the necessary info required to solve the trouble.

First, as I said, I'll check your case and my case again, and then I'll upload in the way you suggest.
I hope that I could learn more from you.

[kid]

what is AMI and GGI ?
and what would be steps converting GGI blocks in file to AMI?

Some guidance plz.

regards

[Santos-Dumont]

Thanks linnemann for sharing your case,

Unfortunately, I didn't succeed in running it. Would you give us a guidance to get it working with AMI or even in GGI or repost this case updated with AMI ??

Thanks,
Charles

[linnemann]

Just unpack it and use it with OF1.6-ext pimpleDyMFoam solver or compile transientSimpleDyMFoam and use that.

[A.Wendy]

Originally Posted by linnemann

Just unpack it and use it with OF1.6-ext pimpleDyMFoam solver or compile transientSimpleDyMFoam and use that.

hi,

i just tried to run this case and i get an floating point exception.
can this caused by a computer problem? i do not get it in my mind why on a different PC the calculation works but not ion mine. i get these error more often.


best wishes

Andy

[be_inspired]

Could you upload the example another time?
I am trying to simulate a HAWT but pimpleDymFoam and CFL limitations is a nightmare when I need results asap.

Originally Posted by linnemann

Hi

You can use this as an example.

http://dl.dropbox.com/u/15968063/3DStruct.TSR1.0.tar.gz

That is a 3bladed VAWT with a NACA0012 profile.

Its done using 1.6-ext but you can change the GGI to AMI and it should work with 2.1. Also I was using transientSimpleDyMFoam and not pimpleDyMFoam.

Also you can't use MRF for a VAWT. When the MRF zone is perpendicular to the flow is generates flow that looks like flow over a cylinder. I cant go into the specifics about this other than tell you that it wont work. The same problem exists in Fluent.