Hi there,
I have a simple test case where cfdemSolverIB gives very different results for the steady state compared to simpleFoam. The velocity field is in pretty good agreement, but the pressure field is completely different. Am I missing something fundamental about pressure in the IB solver or did I make a mistake somewhere in the case setup? Any help would be greatly appreciated.
The case is a single particle fixed in place in the center of a cubic volume. A pressure difference between two opposite boundary patches drives a flow in x-direction, the other patches are pairwise cyclic. Re=3.33 in the attached samples, and the situation does not improve significantly for Re=33.3.
| Attachment | Size |
|---|---|
 Comaprison simpleFoam cfdemSolverIB pressure velocity | 93.53 KB |
| Comaprison simpleFoam cfdemSolverIB pressure velocity rescaled | 88.64 KB |
 cfdemSolverIB case | 9.51 KB |
| simpleFoam case | 6.79 KB |
rubikon2045 | Tue, 09/13/2016 - 15:03
Hello!
When I see this correctly, then the cfdemSolverIB works with a piso-algorithm.
When you use piso, then pressure in simulation p_s is definde as:
p_s = pressure/density
And in simple-algorithm, pressure is the pressure.
Kind regards,
Denis
NTT1508 | Wed, 09/14/2016 - 07:36
Possible smoothing model
I dont think the unit of input pressure is a problem here because two figures show the same velocity and the pressure not too much different. I have not looked your code details, but I feel this might be due to the difference in fluid size and smoothing model. Can you provide details about your meshing?