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Wind Farm Flow Simulation 2

Posted October 6, 2016 at 11:12 by windsimu

I calculated the courant no.

The maximum velocity is approximately 18m/s at the top. and if the time step is 0.15s, the courant no. is 1.08 (dx = 2.5m). So the time step indeed should be decreased. But the time step in the last step is 0.015s, the courant no. is 0.108. It is pretty small. So I slightly increased the time step to 0.05s. I got 1000s physical time after 1 day, so I expect I can get 300-400s physical time after 1 day running.
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Posted in Uncategorized
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Wind Farm Flow Simulation 1

Posted October 6, 2016 at 10:43 by windsimu

I run a simulation case from NREL in OpenFOAM 2.1.1 (3km*3km*1km). I would like to use this case and solver (ABLSolver) to simulate the flow field in wind farm. I refined a region for wind turbine in this case (detx=2.5m).

The case works pretty well before 3035s. From 3035s, the max courant no. increased instantly from 0.75 to 2.6e+25. I used adaptive time step and the maximum time step is set to be 0.5 (it is normally 0.15 because of max courant no.) and maximum courant no. is 0.75....
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Posted in Uncategorized
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Hello All

Posted September 18, 2016 at 15:43 by KTW310

Hi, my name is Keith Wilkins and I am a student at Temple University in Philadelphia, PA. I am studying Mechanical Engineering and just started taking a CFD course a few weeks ago. I graduate this upcoming December and expect to be continuing education in Fall 2017 for a masters, whether it will be in Mechanical or Electrical Engineering is yet to be decided.

So far CFD is very interesting and I am excited to learn more about it so I can use it for my senior design project. I am working...
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Posted in Uncategorized
Views 1014 Comments 1

Dual-Booting : win7 & linux-mint

Posted August 28, 2016 at 18:50 by kindle
Updated June 7, 2017 at 12:20 by kindle (clarity)

Installation from nothing : First win7 then linux-mint.
Win7 writes in MBR something to control boot and linux uses grub to control boot which will be able to boot windows.
Why not in the reverse order?
A complete re-installtion of win7 may over write ALL in MBR meaning the part that will call the actual grub configuration (in /boot or /etc/grub.d not sure...), therefore the repair of the linux booting is needed.
Result: grub boot first, if you choose "windows"...
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Posted in system
Views 1064 Comments 0

Numerics in OpenFoam - PBiCG vs. PCG

Posted August 18, 2016 at 14:13 by kindle
Updated February 23, 2017 at 04:13 by kindle

So the numerical scheme (fvScheme) will affect the property of the matrix to invert and we should choose properly the solver/solving algorithm (fvSolution) in order to solve it properly. Depending on the form of matrix depended on structured or unstructured mesh something like that.

Quote:
Originally Posted by thg
Hi Frog,

Meindert already mentioned, the difference between a PCG or a PBiCG,...
you can find in any textbook about linear iterative solvers like
Wessling, Saad, Trefethen, Stran,....
...
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Posted in Solver
Views 985 Comments 0

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