Complex Geometry

MFiX
#1

I have limited experience using complex geometry using stl. I am apparently doing somthing wrong with this geometry. The geometry is basically a big box with weir obstructions. On the walls, floor and ceiling are various inlets, outlets. I am using an stl to define the geometry. But I don’t see any internal cells when I visualize the vtu files. What am I doing wrong. I will upload the case.

#3

domain_v2.STL (181.6 KB) solids_cooler.mfx (38.9 KB)

#4

I checked the flip normals box in Geometry, but I don’t see FLIP_STL_NORMALS in my mfx file. Does it matter where I manually put it in the mfx file?

#5

Do I have to do it by BC? I am using one stl file and it shows in the GUI pointing in the correct direction.

#6

You need to uncheck “only save data in cut cells”. Right now you only see the “shell” of you geometry. When you uncheck this option you will save both standard and cut cells (i.e. all fluid cells). Your file will become huge because you are saving many variables, It may be worth splitting your data over several files, so it is more manageable.

(I got a slightly better mesh by setting ymin=-2.01, ymax=2.01 and zmax=4.85).

#7

Thanks. I will want to run on a linux machine to run parallel with DMP, but that machine doesn’t support the GUI graphics so I was planning to create the mfx file in windows, then run in linux on a command line. Since I didn’t see FLIP_STL_NORMALS in the mfx file how does MFIX know the normals have been flipped?

#8

Once you have set up your simulation in the GUI, it will generate some geometry*.stl file(s) that include any scaling, translation, rotation, and change in normal orientation. The solver doesn’t use the original stl file, so make sure you copy the .mfx file, geometry_*.stl. The domain_v2.STL won’t be needed.