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Turbulence in hoover helicopter (velocity at inlet=0)

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Old   April 11, 2014, 04:45
Default Turbulence in hoover helicopter (velocity at inlet=0)
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Dear all,

I am currently trying to model the flow generated by a rotating helicopter blade in hoover, using rhoPimpleFoam.

My mesh is a structured mesh, generated using hyperMesh.

I have these boundaries:
- Inlet (face z=zmax), rotor, outlet (z=zmin), symetry 1 and 2 and freeStream.

My first problem (but I think it is solved) is to correct generate the rotating zone. For this, I used the topoSet dict using these option:


name rotor_zone;
type cellSet;
action new;
// source boxToCell;
source cylinderToCell;
sourceInfo
{
// box (0.0 -2.0 3.0) (0.76 2.0 5.0);
p1 (0.0 0.0 -5.0);
p2 (0.0 0.0 5.0);
radius 7.5;
}
}
 

{
name rotor_zone;
type cellZoneSet;
action new;
source setToCellZone;
sourceInfo
{
set rotor_zone;
}

Then I used the option setsToZone -noFlipMap to generate the rotor zone.

In a second time, I extract all face of my rotor zone:

name rotor_zone;
type faceSet;
action new;
source cellToFace;
sourceInfo
{
set rotor_zone;
option all;
}

Finally, I generated the boudary using:
(
{
name rotor_zone;
type faceSet;
action delete;
source boundaryToFace;
sourceInfo
{
}
}
Do you agree with thise methode for generating the rotating zone?

Using rhoPimpleFoam without turbulence (laminar flow), I obtained a correct agreement between CFD and measurements. (Mach number=0.89).

My problem now is to model the turbulence and to run a RANS simulation. In fact, because I try to model a hoover flight, I have a zero velocity at the inlet. So I don't know how to initialize the turbulence. Should I consider the freeStream velocity as the mean velocity of the rotor?
I have studied the mixerVessel tutorial. They model a rotating flow with empty inlet and outlet conditions. I don't understand how they find k and epsilon value.

Does anybody have an idea how to solve this problem?

Thanks you very much,

Best regards,

Martin.
You will find 0 folder attached and topoSet files.
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File Type: zip 0.zip (7.8 KB, 3 views)
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Old   April 23, 2014, 06:19
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Nobody has any idea? I have tried severals boundaries conditions and I have not obtained any converged solution,

Best regards,
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