Error in convergence

Hi all,
I’m stuck with a FSI simulation coupling rigid body dynamic of a falling object immersed in a fluid. I’m using the oasis software with fractional step method for the fluid. The problem is that when the Reynolds number is quite high (900) the krilov solver is not able to solve and diverge. This means that i can’t simulate falling object in air, where the viscosity is low. I have enough computational power, in fact i’m using a cineca server, so i can reduce the timestep until 1e-05 and use a fine mesh (160.000 elements) but after 0.30 seconds of simulations, it crash.

The mesh is good, I evaluated the aspect ratio and other metrics, so i’m thinking the problem is not here, but in the solver or maybe in the method i’ve used.

Any suggestion will be appreciate.

Oasis is verified and validated software and it is highly unlikely that it is the problem in the solver. Without any specification (problem file, error message you received, data visualization), it is impossible to tell any suggestion.