actuationDiskSource without Cp input
 

Hi All,

The actuationDiskSource model in OpenFoam requires both a thrust (Ct) and power (Cp) coefficient to calculate the velocity induction factor a=1-Cp/Ct to calculate the thrust resisting the flow.

I am interested in simply applying resistance to the flow (Ct) and calculating the resultant Cp.

Is there a good reason as to why the thrust force cannot be found through T=1/2 rho U^2 A Ct ?

Why do we need Cp in the actuationDiskSource source?

Many thanks,

Tom Waits

Hi Tom,

I've used actuationDiskSource a lot in the past 2 years for wind turbine modelling, what I found during my search for this was that what is commonly used is what you mentioned, to calculate the Thrust from ct only. Moreover, the induction factor is calculated as a function of ct only: a = 1/2(1-sqrt(1-ct)). This is from the ct definition using the induction factor ct = 4a(1-a).

If you want to proceed with ct only you can do it, but there are some modifications needed to the code (I did it for my MSc project).

You can find some references in:

https://teses.usp.br/teses/disponive...-145825/en.php

SIMISIROGLOU, N. et al. The Actuator Disc Concept in Phoenics. Energy Procedia, http://dx.doi.org/10.1016/j.egypro.2016.09.182

There is much more than this online.

One thing that happened to me is that the power curve I had as reference didn't match exactly with the one I got from OpenFOAM, but it was good enough for my case.

Best Regards,
Luis

Hi Luis,

Your reply is much appreciated. Yes, I would like to proceed with Ct only, especially as I want to calculate Cp when Ct is non-constant across the disk.

I will take a look at your references - if you have anything else useful for this problem at hand that you could post I would be grateful.

Thanks very much once again,
Tom

Hi Tom,

Are you using the ADM for wind turbines?

I saw last week that V2006 of OpenFOAM has some option regarding actuator disk, you can check it out and see if this helps (https://develop.openfoam.com/Develop...tionDiskSource).

Personally, I have not tried it, so I don't know what to expect from the results.

Best Regards,
Luis

Look at my YT video in which I generalized Erik Svenning's actuator disc. You can calculate the pressure drop in ParaView and the solver gives you the thrust.
https://www.youtube.com/watch?v=MbqbgGLJRso

Link to the solver: https://github.com/EdgarAMO/multipleDiskSimpleFoam

Link to the case file: https://github.com/EdgarAMO/actuator-disk-farm

Hola Edgar! Thanks for sharing your work on reproducing Erik's tutorial.
I could not find available your video on Youtube. If you still have it, can you share it via cloud?