Learning Forum

[Laurens]

Hello,

I am looking for two correct expresions to see the added mass and the expected mass to the system in a dynamic simulation. My case is transient, incompressible, predefined dynamic wall movement and predefined velocity profile. Now I would like to see if the velocity inlet matches the volume expansion, to account for mass conservation. 

So I would like to compare added mass to the system vs. expected mass from volume expansion as a report definition. I got this so far:

For inlet:  MassFlowInt({flow-time},['inlet'])

For interior: VolumeInt({flow-time},['base_surface'])*AreaAve(Density,['interior-base_surface'])

But looking at the residuals during calculation, this does not seem correct. Am I doing something wrong?

Kind regards

[Rob]

Not sure. I'd tend to monitor mass entering, mass leaving and a volume integral of what's in the domain. Then do all of the maths in Excel. 

If you're looking at what's inside the domain why are you using volume integrals of what looks like a surface?