Discussion Forum

Hi all,


I am studying a microfluid case about a nano needle inside a fluid channel, the size of needle is about 1 micron and the size of channel is 200 micron. I simulate this case fairly OK in 2D, but when I trying to convert it into real 3D case, lots of problems occur.


First is about meshing. When I trying to use finer mesh, it keeps telling me "out of memory". When I try to use coarser mesh, it told me fail to do something with "layer". Even when I was luck, there is no error, there are still some yellow exclamation mark in mesh. I don't know how to use advanced method to deal with it. ( 1 micron needle and 200 micron channel is the real case, I can't change this ratio)


Secondly, even though I got no problem with meshing, I face enormous errors about computing. "Out of memory" is most common, and sometimes "fail to find solution". I enlarge the size of my needle a lot at last, to 50 micron actually. In this case, Comsol works and get the result in fairly short time. ( But if I make the size smaller, it fails again)


I just wonder if there is any advanced setting that I may use. ( like how to make the needle not look like singularity, how to let mesh be smarter, how to use more memory) Or, is it just the shortcoming of Comsol that cannot deal with this kind of case? (I don't think this possible, because my model is really very basic)


Thanks for anyone who helps.



Mao