[peatmac]

Hello,

I am modelling a cylinder oscillating in a uniform current due to VIV. The simulation will run up to about 25 seconds flow time, but then it fails due to a pressure correction.
I have had a read through all the other threads available about trying to solve this problem. I am running the simulation with PISO pressure-velocity coupling with skewness-Neighbour Coupling disabled. My URF values are 0.3,1,1 and 0.7 - Pressure, Density, Body Forces and Momentum respectively. Under the Discretization tab the pressure is set to Standard and Momentum as Second Order Upwind.
I have tried to change all these values but with still no success.

However.

When I change my time step from 0.001 s to 0.003 s the analysis will keep iterating. If I let it run at this time step I run into a negative cell volume in my mesh, but If I quickly change the time step back to 0.001 s after 1 or 2 iterations the analysis will run for about 10 more time steps then fail due to a negative cell volume.

Can anyone please advise me on how to resolve this problem?

Many thanks.

P.