[liuyang]

Hi former:
I used version 1.5 for flow around oscillating cylinder,but it seems that two files:
cellMotionU and pointMotionU.
I used a file pointMotionU like this:
dimensions [0 1 -1 0 0 0 0];

internalField uniform (0 0 0);

boundaryField
{
cylinder
{
type oscillatingVelocity;
omega 0.1;
amplitude (0 -0.628318531 0);
value uniform (0 0 0);
}
up
{
type fixedValue;
value uniform (0 0 0);
}
down
{
type fixedValue;
value uniform (0 0 0);
}
inlet
{
type fixedValue;
value uniform (0 0 0);
}
outlet
{
type fixedValue;
value uniform (0 0 0);
}
frontAndBackPlanes
{
type empty;
}
}
and the same for cellMotionU. There seems to be something wrong, the error message is:
gradientInternalCoeffs cannot be called for a genericFvPatchField (actual type oscillatingVelocity)
on patch cylinder of field cellMotionU in file "/home/ly/OpenFOAM/ly-1.5/run/os_cyclinder/0/cellMotionU"
You are probably trying to solve for a field with a generic boundary condition.

Then what should the file cellMotionU should look like?
Thanks a lot.

[mathieu]

Hi,

I think removing the cellMotionU file from the "0" directory will solve the problem.

Mathieu

[liuyang]

Hi:
Following your instruction,it works now.Thank you very much.

LiuYang

[patriem]

Hello,

for an oscillating sine motion with vel_amp_x=0.226m/s and frequency of 128Hz i used oscillatingVelocity and a pointMotionU with


type oscillatingVelocity;
omega 804.096; //=2*pi*f
amplitude (0.226 0 0);
value uniform (0 0 0);

But the oscillating amplitude seems to be much too high. what do i do wrong? The oscill....C file under fvMotionSolver/pointPatchFields/derived/oscillatingVelocity
is standard with
(p0_ + amplitude_*sin(omega_*t.value()) - p.localPoints())
/t.deltaT().value()
);

Thank you for a hint

[ssp]

Patrick,

You need oscillatingDisplacement and not oscillatingVelocity. Are you using OF 1.5? Have you had any problem with oscillatingFixedValue?

Sopheak

[patriem]

Hello,

I don´t think that i MUST use oscillatingDisplacemt. I can also describe the motion by oscillatiingVelocity, with the maximum value of velocity as the amplitude, and omega as 2*pi*f.

I want to use it for pointMotionU, the inputfile for velocitylaplacian (dynamic mesh). The oscillatingFixedValue b.c. is not supported here, so i need oscillatingVelocity.

COuld you tell me the correct entries and meanings for omega and value uniform? By the way, what is p0?

[patriem]

can´t anybody help me? tried it again today, but the meshmotions isn´t the expected. the amplitude is much too high!

[ssp]

Patrick,

Try to use oscillatingDisplacemt on the velocity field and you will be suprise. Just change oscillatingVelocity to oscillatingDisplacemt.

Sopheak

[ssp]

like this:

type oscillatingDisplacement;
omega 804.096; //=2*pi*f
amplitude (0.226 0 0);
value uniform (0 0 0);

[patriem]

Thank you very much, i am one step further right now!

I could change the sin to a cos-motion by editing the oscillatingDisplacement...C file. And it still works.

Patrick

[patriem]

I have to mention that there were of course changes in the dynamicmeshdict (to displacementlaplacian)
fvsolution and fvschemes necessary. and the file in 0 should be called pointDisplacement.