[ufocfd]

Has anyone found a successful implementation of the actuationDiskSource method in simpleFoam (for a helicopter rotor disc type calculation) ?

I am investigating 3 methods which apply a source term on the prescribed rotor disc region (cell zone), namely:

1. mean velocity source
2. actuation disc source
3. rotor disk source


The problem I have with actuation disc source is that the prescribed values for CT and CP (thrust and power coeffs) are somewhat unstable. Using values such as 0.5 & 0.5 does nothing much, whereas larger values CP=1.0 CT=0.1 and the solution becomes unstable. It also seems sensitive to the location of upstreamPoint(x y z).

I wonder if this method is at all suitable for helicopter (or fan) rotor disc and maybe its supposed to be used only for wind turbine type calculations...?

This is what I have so far in fvOptions:

disk2
{
type actuationDiskSource;
// variant Froude;
// variant variableScaling;
active on;

actuationDiskSourceCoeffs
{
selectionMode cellZone;
cellZone rotordisc;
fieldNames (U);
diskArea 0.4;
diskDir (0 1 0);
Ct 0.5;
Cp 0.5;
upstreamPoint (0 0.5 0);
}
}


Regards Giles.

[JulioPieri]

I haven't used, but from the equation, as Ct gets larger, the Thrust increases a lot.

Have you tried using other force method? Have you tried increasing Cp and Ct slowly, while letting the solution get stable at each change?

Maybe you are abruptly increasing the parameters, causing it to diverge. Try running with 0.5/0.5 for a while, then increave to, say 0.6/0.4, run for a while, etc.

[ufocfd]

good suggestions - thanks Julio.
I will repost if/when it works ok.