[Volkanatar]

Hello Foamers,

I am working on a case of interFoam. It's like a mixing process. I start the simulation with setfields. So there is no inlet. It's closed system. There is only one outlet which i want to have for a certain period of time opened and closed. I have used codedMixed BC on my outlet for the U:

outlet
{
type codedMixed;

refValue uniform (0 0 0);
refGradient uniform (0 0 0);
valueFraction uniform 1;

name codedauslass_U_BC;

code
#{
const scalar t = this->db().time().value();
const scalar period = 0.09;
scalar timeWithinPeriod = fmod(t, period);
if (timeWithinPeriod <= 0.045)
{
this->valueFraction() = 1;
this->refValue() = vector::zero;
this->refGrad() = vector::zero;
}
else
{
this->refValue() = vector::zero;
this->refGrad() = vector::zero;
this->valueFraction() = 0;
}

#};
}

For some time at the begining it seems like it's working but later during the simulation the volume of the liquid which i'm interested in starts to increase for some time and then it starts decrease again kinda back flow effect.

Is there a way to overcome this problem?

Thanks in advance.

[NotOverUnderated]

If you are interested in closing/opening the outlet progressively, you may need to use cyclicACMI BC.

Regards

[Volkanatar]

Thanks for your reply and the hint. Could you tell me any tutorial about that? I used to use cyclicACMI boundary type when i had a symmetric rotational sliding mesh to overcome the problem with low weight values of the AMI which were approaching to zero and eventually simulation stops.

I can't really imagine how to use that cyclicACMI otherwise for the outlet.

Thanks again

[Volkanatar]

I think i found a tutorial about that TJunctionswitching. I'll take a look into that tutorial. Thanks for your hint.

[NotOverUnderated]

Hi,

You can also check this tutorials by Tobias on his website:
https://holzmann-cfd.com/community/t...-heat-transfer

For the list of tutorials, see this page: https://holzmann-cfd.com/community/training-cases

I hope that helps

Kind regards