[alexya]

Hi, guys:

I'm new to openfoam. I have implemented a steady state flowRateInletVelocity in OF5 and it works:

Inlet
{
type flowRateInletVelocity;
volumetricFlowRate 3.0;
value uniform (0 0 0);
}

But, when I try to have a time-varying polynomial flowrate:
Inlet
{
type flowRateInletVelocity;
volumetricFlowRate polynomial ((3.0 0) (0.2 1)); // = 3*t^0 + 0.2*t^1
value uniform (0 0 0);
}

The simulation blows up. Even if I test polynomial ((3.0 0) (0 0)), which should be the same as constant flow rate 3.0, the simulation blows up.


Is there anything wrong with the syntax of using polynomial for flowRateInletVelocity? Or the polynomial variable is no longer the time "t" but something else in OF5?


Alex

[arvindpj]

What are you trying to achieve?

Are you trying to run simpleFOAM (steady) with ramping flowrate with increasing iteration

or

run a pimpleFOAM with pseudo steady with ramping flowrate with time>

Cheers,
Jay :-)

[alexya]

Hi, Jay:

I am doing a time varying flowrate by running pimpleFOAM. The time varying flowrate is prescribed by a polynomial, like Q=a*t^0+b*t^1+c*t^2+d*t^3+.............

It should be straight forward syntax as it is used in uniformFixedValue boundary condition. I'm just wondering is there any change with the syntax for "flowRateInletVelocity" in latest OF5? Or what is the right way to do it in OF5?

Thank you!
Alex

[arvindpj]

I thinl you are missing the uniformValue keyword before the polynomial

volumetricFlowRate uniformValue polynomial
(
(3.0 0)
(0.2 1)
); // = 3*t^0 + 0.2*t^1polynomial

[Santiago]

Well, your simulation blows up because as t-->infinity, Q-->infinity