MicroHH is an open source computational fluid dynamics code for 3D simulation of flow in the atmosphere that I designed and co-developed. The source code is hosted on GitHub. A detailed description of MicroHH is published in Geoscientific Model Development.
Below you find two animations. The first is of tropical deep convection following the Radiative Convective Equilibrium Model Intercomparison Project (RCEMIP) specification, the second is of a Rayleigh-Taylor instability. More movies can be found on MicroHH's Vimeo channel.