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New! Turbinesiting tutorial

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Old   December 10, 2011, 09:32
Default New! Turbinesiting tutorial
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Jack Konnal
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Hi Guys,

I'm very new to CFD and OpenFOAM, but I'm interested in learning more about it! I've got a terrain that I'd like to model wind flow over, much like in the tutorial 'turbinesiting' in windSimpleFoam. I've used GPS coordinated to create an .STL file with my terrain on. I've got SnappyHexMesh working correctly in my blockMesh.

I just want some guidance on how to fill out the boundary conditions, mostly U and P in the '0' folder (using the 'turbinesiting' as a template). It would be good to just test my model with some random values for this to see how it runs.

Any help would be much appriciated.

Thanks
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Old   December 11, 2011, 01:05
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Alan Russell
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The turbinesiting tutorial sets pressure boundary conditions in the /0 p file - use exactly the same pressure setup for all boundaries. The wind velocity is in the /include ABLCondidtions file (Uref). If you aren't familiar with the other variable names, the parameters in this file set up an inlet velocity profile (Ustar - friction velocity, z0 - atmospheric roughness height, Uref is the wind speed (m/s) at Href - meters above the zGround elevation).

To start, I would copy the entire turbinesiting tutorial, rename it, and use your own mesh. You will need to have z as the vertical axis in the domain, and set zGround as the minimum elevation of your terrain in meters. If you already have a good mesh with your own terrain, you've made a lot of progress! To move your mesh around, go to the directory where you ran snappyHexMesh and copy the /3 polymesh file to the replace the turbinesiting tutorial polymesh directory. You can experiment by changing Uref to increase or decrease inlet wind speed. Good luck,
Alan
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Old   March 10, 2012, 10:13
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Jack Konnal
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Hello again. Thanks for the previous help, unfortunately I've been unable to look at it for a while due to other work!

I had a bit more of a play around with it a few days ago. I've managed to run windSimpleFoam on my 2D terrain in my mesh. This is however where my problems lie. The wind, which should flow from left to right over the terrain definitely doesn't look correct when viewing the glyphs on ParaView. I thought it must be something to do with my boundary conditions, but I am as yet, unable to find the source of the problem.

I have attached a few screen shots, one showing the wind I'm getting through the mesh, another of the present boundary conditions and also of the ABL conditions. As I said previously I'm very new to this, hence why my mesh is currently very simple - will be refined once I can get flow running through it!

Any help would be hugely appreciated! Thanks
Attached Images
File Type: jpg Flow1.jpg (93.8 KB, 167 views)
File Type: jpg ABLconditions.jpg (82.4 KB, 98 views)
File Type: jpg boundaryconditions.jpg (80.8 KB, 96 views)
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Old   August 1, 2012, 23:02
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Quote:
Originally Posted by bathgooner View Post
Hello again. Thanks for the previous help, unfortunately I've been unable to look at it for a while due to other work!

I had a bit more of a play around with it a few days ago. I've managed to run windSimpleFoam on my 2D terrain in my mesh. This is however where my problems lie. The wind, which should flow from left to right over the terrain definitely doesn't look correct when viewing the glyphs on ParaView. I thought it must be something to do with my boundary conditions, but I am as yet, unable to find the source of the problem.

I have attached a few screen shots, one showing the wind I'm getting through the mesh, another of the present boundary conditions and also of the ABL conditions. As I said previously I'm very new to this, hence why my mesh is currently very simple - will be refined once I can get flow running through it!

Any help would be hugely appreciated! Thanks


Hello!

I am using the same tutorial to help me understand how to implement a rough wall boundary conditions

I tried to change the Ks value in the nut file in 0 folder but it is giving me the same velocity field every time ... is this nutkRoughWallFunction really working??

Please see the attached photos!

Thanks for your explanation!
Attached Images
File Type: jpg snapshot1.jpg (26.3 KB, 105 views)
File Type: jpg snapshot2.jpg (20.4 KB, 57 views)
File Type: jpg snapshot3.jpg (21.6 KB, 54 views)
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Old   March 2, 2013, 19:04
Default Master Thesis that contains good info on Turbine Sitting
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Jose Rey
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There is a master's thesis by Benjamin Martinez from Rizo-DTU in 2011. It contains some good information which is relevant to the Turbine Sitting Tutorial. He talks about the version in OpenFOAM 1.7, but I don't think the tutorial has changed much. He gives good information about nutRoughWallFunction.

http://windenergyresearch.org/downlo..._MScthesis.pdf

Best.
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