Hello, I am using cfdemSolverIB in a simple case, trying to measure effective permeability of a pack of spheres. I need to resolve the flow behaviour explicitly. I based my case on the twoSpheresGlowinskiMPI tutorial.
I have two cases with the exactly same configuration except for the time-step for the CFD part (and the coupling step) (DEM time-step is kept constant). Although the behaviour in both cases looks physically plausible, the pressure drop behaviour change dramatically with the value of the time-step for CFD solver.
I went through the solver code but so far I am unable to find where the problem can be.
I do not think it adds information but I follow the problem until the line 225 " particleCloud.calcVelocityCorrection(p,U,phiIB,voidfractionNext); " that is the interaction with particle field.
This behaviour occurs in other cases I was analysing and it is always the same, as smaller the time-step value for CFD, as higher the pressure in the system.
I am attaching both cases and the plot of the pressure drop after 1 second simulation (the solution is stationary after 0.05 second) in both cases. It is a 2d case.
I will keep working on this and update if I solve it.
thank you.
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 cases.tar_.gz | 603.17 KB |
j-kerbl | Wed, 06/07/2017 - 11:49
Hi Paula,
Hi Paula,
thanks for sharing the case, I'll look into this.
Cheers,
Josef
bajucjoy | Fri, 10/19/2018 - 13:24
Hi PAULA
Did you find an explanation for this. I have been trying to use solverIB for resolving flow through a packed bed. The pressure drop results I am getting are also very different.
Thanks