Lethe 1.0: An open-source parallel high-order computational fluid dynamics software framework for single and multiphase flows

Lethe is an open-source Computational Fluid Dynamics (CFD) software framework with extensive multiphase and multiphysics capabilities. By leveraging the deal.II open-source framework, Lethe finite element solvers scale well on modern high-performance computers while possessing advanced features such as dynamic mesh adaptation, load-balancing, isoparametric high-order capabilities, and a fully-fledged Discrete Element Method (DEM) module. To facilitate contributions from the community, Lethe is extensively tested with continuous integration using over 450 unit and functional tests. Furthermore, Lethe contains 74 fully documented examples with pre-processing and post-processing steps to allow users to learn how to rapidly use and modify the framework. In this article, we give an overview of the simulation models available within Lethe and illustrate these capabilities with a selected list of examples including turbulent and multiphase flows.