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High Aspect Ratio Meshes
Posted 22.09.2016, 13:44 GMT-4 0 Replies
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I am modeling a problem in the creeping flow module and having issues with meshing. The problem is composed of two "nearly" touching spheres of equal radius surrounded by fluid. I am interested in what's happening between the spheres (high pressure and velocity gradients), so I need a fine mesh here. The difficulty is that the gap between the spheres is ~Radius/10^4, so I need very small elements that grow to larger elements away from the gap.
My geometry has a small cylinder in the region between the spheres where I built the fine mesh with swept quadrilateral elements of "size" separation*5 and "distribution" of 2. This results in 2 elements across the separation and a sweeping element size of separation*5. The simulation takes ~1hr to run with an iterative multigrid method and uses ~4GB ram in the process. Now, the results aren't what I'm expecting and I'm getting ~8% error in my solution, compared to the analytic solution. I tried increasing the "distribution" to 4 or even 3 elements across and the ram increases to nearly 20GB, even though this isn't a significant jump in DOF and the solving times would be unrealistic.
Does anyone have a recommendation on different types of elements to use or other methods of meshing? Also, I'm using P2+P1 discretization.
Thank you everyone!
Hello Adam Woodman
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