SimScale CAE Forum

Volumetric Flow Scale


#1

Public Project: NormalSinoNasal03 – https://www.simscale.com/projects/mdunha/normalsinonasal03/

This is a prototype for an aerodynamic study of the nasal cavities and paranasal sinuses. The model was constructed from a CT scan dataset.

The native model has dimensions in cm. I use a 0.01 geometry scale factor. The volumetric flows under normal physiologic conditions are specified in ml/s. In this case 180, 560 and 1100 ml/s (cm^3/s). I convert the ml/s to m/s when specifying the inlet volumetric flow by multiplying by 1e-6.

The expected changes in the velocity fields with increased flow rates do not seem to appear. Am I missing something in the unit conversion? Does SimScale perform any conversion on the flow parameters based on the geometry scale factor?

The screenshots depict fully developed flows at 180 and 1100 ml per second.Paraview%20Screenshot%20Normal%20180%20mlpers|690x345

Thanks.

Michael


#2

Hi Michael,

did you check the dimensions when uploading the geometry and if they fit the scanned data? If there is anything odd about the scaling you can change that by adding a geometry operation (clicking on the geometry and choose the option Scaling) - is that what you meant?

Best,

Jousef


#3

Yes, I checked the geometry and did apply scaling - cm to m. The question is do I also need to scale the inlet boundary flow condition from ml/s to m^3/s or is this automatically taken care of by SimScale.

Thanks.

Michael


#4

Hi Michael!

The dimensions are already set no matter if you work with SI units or anything else - you can see the deposited units next to the input fields. Let me know if that answers your question.

Best,

Jousef


#5

I verified that the units are properly scaled. Working on simulation parameters.
Thanks.

Michael