Divergence in Star-CCM+ and Abaqus Co-simulation: flow pass a flat plate
 

Hi all, I have tried the "Abaqus Co-simulation: Mechanical Coupling" tutorial and reproduced it in my own way(without using the input file and volume mesh file provided). Now, I want to run a set of simulation that is very similar to this tutorial.

The new flat plate has a different dimensions (length=0.125m, width=0.025m, thickness=0.0025m). The medium is replaced by water instead of air. I use the same physics models with the tutorial. Besides, I have defined a new material for the flat plate (E=0.93GPa, poisson ratio=0.46).

But when I'm trying to run the simulation, it diverged. During the calculation, the pressure on the flat plate's surface become extremely large and the value is alternating between positive and negative (meaning it has large positive value in the current time-step, followed by a large negative value in the next timestep). This trend continues until the plate deforms weirdly then, it diverged. This happened in the first few time-steps.

First, I thought it was the large deformation that contributes to this instability, so I changed the coupling method from explicit to implicit in order to reinforce the coupling. The calculate got a little bit better but at some point it still diverge (the divergence delayed). I have reduced the time-step as well but it is not helping.

Is there anyway to solve this issue?

Regards,
Bin