Abstract

Numerical simulation of continuum mechanics equations poses an interesting challenge in the compromise between software efficiency and flexibility in expression of complex and coupled equation sets. While in some cases Computational Continuum Mechanics (CCM) simulations are a matter of routine industrial practice – such as Computational Fluid Dynamics (CFD) – there exists an enormous scope where identical discretisation tools may be used on other equation sets. One possible answer to this challenge is the programming technique of object orientation. OpenFOAM (Field Operation And Manipulation) is an open source object oriented numerical simulation library aimed at complex physics modelling and will be described in this seminar.

OpenFOAM handles continuum models by mimicking partial differential equations in software. Polyhedral Finite Volume discretisation is implemented in operator form (e.g. temporal derivatives, gradient, divergence, source and sink terms), and operators are combined to form equations. Efficiency and elegance in implementation are achieved through layered development and extensive code re-use, where various components (e.g. mesh handling, field algebra and calculus, discretisation, linear algebra and solvers, dynamic meshing etc.) are developed and validated in isolation. Combination of individual blocks results in a powerful, flexible and efficient industrial-strength software solution. Auxiliary tools support the basic solvers, providing pre- and post-processing interfaces, dynamic mesh handling, real material properties, massive parallelism, Lagrangian particle model and other tools present in a modern CFD solver. The library is completed with a suite of relevant physical models. Today, OpenFOAM is a leading Open Source CFD tool with over 100000 users in industry and research community.

In this talk, ideas underlying the design of OpenFOAM, critical efficiency components and various examples of application will be presented, ranging from external aerodynamics, multi-phase and free surface flows to more interesting examples of Multiphysics and strongly non-linear equation coupling.