Probably the biggest SPH simulation for fluid dynamics.
The interaction of a large wave with an oil rig is simulated using the MultiGPU implementation of DualSPHysics (http://www.dual.sphysics.org).
This simulation which involves more than 10^9 particles is, as far as we know, the largest simulation using GPUs in computational fluid dynamics.
It was carried out using 64 GPUs Tesla 2090. To simulate 12 seconds of physical time, a total number of 237,342 steps have been carried out in 91.9 hours.