Hi there!! I'm geting desperate because of following: I am simulating a free fall of droplet. When the droplet diameter is of 2mm, then it works quite well. Fluent results agree well with newton formula (dynamic drag considered). However, when the droplet is smaller (0.2mm in my case) then the droplet acceleration is much smaller and the terminal velocity as well. It is definetly crap.. I found that the surface tension causes this strange happening. Does anybody has any explanation for that?? many thanks!!! bohis

Hello bohis

one point amongst many others may be that your mesh isn't fine enough to resolve droplets of 0.2 [mm] properly. Therefore the reconstructed curvature of the free surface and consequently surface tension effects are wrong or at least a rather rough estimation of the real situation?

cheers Max

my mesh is quadrilateral. I am using axisymmetric model. I think my mesh is fine enough. Element size was 1/64 of droplet diameter for the case with coarsest mesh (1/512 for the finest mesh) for vof discretization, I employed HRIC scheme. Velocity-pressure coupling was provided with PISO. After so many calculations, I would doubt that it is even possible.. any other suggestions????????pls!!!!

bohis

[monty_p20]

Hi ..

Can u help me please about droplet simulation through pipe using vof model..


thanks