Large Eddy Simulation
LES is a method for simulating complex flows with spatial and temporal resolution, where all time-scales are simulated and spatial resolution is filtered. The filter width is usually a function of grid point spacing or derived distances. By applying fewer model assumptions many flow phenomena, that are inaccessible otherwise, can be simulated in detail. LES is a computationally intensive method that is inherently unsteady.
The following video shows the results from a LES simulation. Gaseous fuel (Methane) and air are mixed in a highly swirling burner. The iso surface has a gas concentration of 5% (v/v) and is coloured by velocity magnitude. The used turbulence model is LES Smagorinsky. The mesh is purely hexaedral and contains 4.7 million finite volume cells.
Comparison of unsteady simulation between CPU and GPU: