is interFOAM restricted to certain length scales?
Hi Foam devs;
This is my 1st report and hope you guys help me out. I report this issue as I found nothing really related to this issue nor anyone could answer me in CFD online!! I use interFOAM solver and using capillary-rise tutorial.
My problem is related to 2D usage of the capillary tube with an "empty" boundary condition. (I use g = 0m/s2).
I deal with micro-channels. So, I am usually dealing with length scales of 1e-6m and below.
As I understand from "empty" b.c. "nothing (no computation)" is being done along the empty dimension. What happens along other 2 axis is projected along the 3rd dimension.
As you see in the attached word doc, I performed several test cases over different length scales of the capillary tube and I see a severely diffused interface when I change my 3rd dimension. {Or to be more specific when the cross sectional area of the capillary tube is below 2e-10 m2}. Being an empty b.c., I would not expect this behavior and would expect a sharp interface for any value used in the 3rd dimension. Is there a limit based on length scales (or cross-sectional area of capillary) to which we can use interFoam? Important to mention that I tried even with a very small time step as well with no improvement of behavior. Also checked the case with a compression factor of 4 and grid refinement. Still the problem exists. Really interested to know why this behavior is seen. As an example also attached a test case where the interface is getting diffused. interface_report..docx interfaceSmaring3BbNum1we-8.zip Thanks and best; Saideep