The Palabos library is a general-purpose computational fluid dynamics (CFD) library, with a kernel based on the lattice Boltzmann (LB) method. It is used both as a research and an engineering tool.
Palathark is an open source lattice Boltzmann library written in Futhark. Its aim if to be agnostic of the underlying hardware (single core CPU, GPU, multi-threaded CPU, ...) while remaining very efficient numerically. It is an active research topic.
An open source agent based pandemics simulator based on the A/B street traffic simulation game. Currently under heavy development.