[Bowman]

Hi,
I am a student and I have been working with OpenFOAM for a few months. I have seen various posts about turbine simulations within OpenFOAM here on CFD-online. I am currently using the actuationDisksource within fvOptions in OpenFOAM for a horizontal axis hydrokinetic turbines. My plan of study is to test each type of model (actuationDisksource, radialActuationDisksource, rotorDisksource, possibly an actuator line model, and finally a fully resolved turbine). I am just starting and I have noticed that within OpenFOAM there are the force and forceCoeffs functions. I am of course, interested in the power and thrust on the Disk(the swept area of the turbine blade). What is considered the typical/standard process among users to calculate these performance parameters? Is this done through a matlab or python script reading in the force output or is there a calculation feature with OpenFOAM?

The versions of OF that I have access to at my facility are 2.3 and v1606+. All grid generation is done through Pointwise and post-processing is done through either ParaView or Ensight.

Thank you and any help would be greatly appreciated,
Josh

[tareqkh]

Hi Josh,

I have attached a file where you will be able to extract the volume forces. I am assuming that you are using the actuator disk model and you have a file named volume VolumeForce in the 0 folder! You need to copy the file to the system folder. Perform the simulation once it finishes type sample in the terminal. Finally, you need to adjust the coordinates of the sampleDict to the coordinates of your turbine in the mesh i.e. the radius of your turbine and the location.

Also, you can integrate the pressure over the whole disk to get the total thrust. You could extract the pressure over the disk then use Matlab (trapz) to perform the integration.

Best,

[Bowman]

Thank you Khamlaj!
I do not have a file named VolumeForce in the /0 folder. That is something I'll need to do. Could you point me in the right direction to see how this is implemented? I use Pointwise for meshing. So the disk volume is set to cellZone. I am assuming that within the file VolumeForce, I will specify my cellZone for disk? I'll upload my case when I get back to the HPCC. However, I am essentially just modifying the turbineSiting tutorial in simpleFoam to fit my mesh.

Here is what I am trying to simulate. An actuator disk model with a hub/support structure. As of right now, I only have the actuator disk model without the hub/support structure but it does have a hole through it.

U_magnitude_Iso_surface_and_vector_clip.jpg

AD_mesh_with_hole.jpg

AD_mesh_support_model.jpg

[pbachant]

I see two options here:

1. Use an instance of a probes functionObject at the actuator disk's upstreamPoint, which can then be used to calculate power with 1/2*rho*A*U**3.
2. Modify actuationDiskSourceTemplates.C to print the upstream velocity at each iteration. At line 57, you could add

Info<< "Upstream velocity for " << name_ << ": " << upU << endl;

[hoemmaria]

Hey Josh!

Did you find a good way to calculate the power from an actuator disk? I am doing the same for my master thesis. However, I do not have a constant loaded disk, but more of a gaussian load distribution.

Kind regards,
Maria

[KimBest]

Hi,


I am having to do a similar thing. Would I be right in saying that the purpose of upstreamPoint is to record a value of velocity at a specified coordinate, for the purpose of calculating power?


If so, does this mean pasting the code posted above:



Info<< "Upstream velocity for " << name_ << ": " << upU << endl;


in the aforementioned file will output this velocity to be used in the calculation?


Thanks,


Kim