Moving geometries like paddles, turbines, mixers and blowers still pose great challenges for computational fluid dynamics. The physically correct prediction of flows in moving geometries is unsteady and computationally expensive. In this particular field CFD is often the method of choice, if the machines are experimentally inaccessible or the experimental costs, caused by down-time and / or loss of production, are too high.
The video shows an unsteady simulation of a mixing process. The iso-surface of the 10% concentration of the phase to be mixed is plotted as well as the velocity magnitude and the time dependent inhomogeneity of the mixture.
Following video shows another example of a cfd simulation of moving geometries: a wind turbine. An iso-surface of constant vorticity is coloured by velocity magnitude.