Learning Forum

[ayang1]

 

Hello! I am trying to model the flow of air over 3 2D cylinders (75ft in diameter each) in this configuration. I am quite new to Fluent and need some help sizing my mesh so that I get a structured topology. Could someone please advise me on whether this is a geometric issue or a meshing issue? Thank you.

[Rob]

Don't. Remove the decomposition and use inflation plus hex pave mesh. All a map mesh is going to acheive is wasted, possibly skew cells. Fluent is an unstructured solver so even a fully (sub)map mesh won't be treated differently to a hex pave in numerical terms. 

Your priority is radial and inflation resolution followed by the wake region. 

[ayang1]

Thank you!

[Rob]

You're welcome.

Just as aside, 75ft suggests a tank farm/silos. You may want to look at 3d effects too. For interest look up Ferrybridge C's mishap in 1965, it's in the UK. 

[ayang1]

Yes, I am doing a study into tank farms! Specifically, I'm trying to investigate local wind acceleration caused by tank farms and if that could lead to deformation in downstream tanks. I've been running 2D simulations to keep runtime reasonable as I analyze the pressure distrubution under various parameters (spacing ratio, wind speed, etc). If you are familiar with similar experiments, please point me towards any literature! 

Also, I tried taking your advice and implemented edge sizing + face sizing + inflation (120 edge divisions around the cylinders, 2m element size for the face, first layer height of 0.0004m, max layers=20, and growth rate=1.2). Below is my mesh. Is this good enough?