[nanavati]

Hello All,

How do I change mass flow rates at inlet, only for a certain timesteps ?

for example, as of now my inlet U patch is,

Inlet
{
type flowRateInletVelocity;
massFlowRate constant 0.00195277; //= 7 kg/h
rhoInlet 1.188;
value uniform (1 0 0);
}

where as you can see Mass flow of Air is 7 kg/h (0.00195277 kg/sec)


now what I want to do is,

I want to change this mass flow from 7 to 5 kg/hr, only for a period of 2 seconds. then back to 7 kg/hr.

(simulation controlDict; startTime is 0 sec and endTime is 10 sec)


I guess this can be done by groovyBC, but i have no idea how to change the boundary condition and its expressions.

[mgdenno]

Try this http://www.openfoam.org/version2.1.0...conditions.php

[nanavati]

Originally Posted by mgdenno

Try this http://www.openfoam.org/version2.1.0...conditions.php

Thanks for the quick suggestion.. It works like a charm !

[nanavati]

Originally Posted by mgdenno

Try this http://www.openfoam.org/version2.1.0...conditions.php

I modified my Inlet BC as,



Inlet
{
type flowRateInletVelocity;
massFlowRate tableFile;
rhoInlet 1.188;
tableFileCoeffs
{
fileName "$FOAM_CASE/ramp"
outOfBounds clamp;
}
}

and in my Case folder I made on file named ramp

which contains,

(
(0 0.001952)
(7 0.001952) // from 0 to 7 miliseconds, constant flow
(8 0.003888) // from 7 to 8 miliseconds, increase in flow
(9 0.001952) // from 8 to 9 miliseconds, decreasing it again to initial value
)