I use STL to define the geometry and get this error
Error set_phase_index 148case.zip (86.1 KB)
INFO check_geometry.f:191
Info: DES grid size:
DESGRIDSEARCH_IMAX = 30
DESGRIDSEARCH_JMAX = 106
DESGRIDSEARCH_KMAX = 2
The particle density in particle_input.dat (2526 kg/m3) doesn’t match the density defined in the solids pane (2530 kg/m3).
Thank you. I have two another problems.
The first is that the normals of the stl file always points to the region deleted from the fluid domain region. When I check the Flip STL from the mesh>mesher panel, the normal does not change. Are there any problems with my operation?
The second problems is that can I draw an STL file like the figure. I want the fluid domain the region inside the big box but outside the four small boxes. How to set the normals in this STL? Is there any tutorial about complex stl setting?
The Flip STL from the mesh>mesher panel reverses the normals internally (when pre-processing occurs in the solver), it does not change the original STL file. This is a legacy keyword. For 19.1 version onward, it is better to flip the normals in the GUI and visualize the results:
Regarding the second question, since all the geometric elements are rectangular, you will get better results defining rectangular regions, i.e., you don’t need stl files. Of course your mesh must be sufficiently fine to resolve the small obstacles. If you even need to use stl files for similar configurations and non-rectangular geometries, make sure the normals point towards the fluid region. All CADs should have some option to control/flip normal vectors.
As Jeff mentioned, when rectangular domains (including internal rectangular domains) are simulated, it would be better to define rectangular regions and specify walls for internal rectangular sub regions. Actually in MFIX, all rectangular domain boundary, user specified walls and impermeable surfaces are first converted to STLs internally for particle-wall collisions (see stl_preproc_des_mod.f for more details).