Evaluation of OpenFOAM’s discretization schemes used for the convective terms in the context of fire simulations

The influence of the numerical schemes used for discretization of the convective terms in the momentum equations and in the transport equations for scalars is investigated. To this purpose, a set of problems with exact solutions, the Taylor-Green vortex problem, an isotropic decaying turbulence problem, along with two well-known fire configurations, namely the Sandia's helium plume and McCaffrey's fire plume experiments, are considered for evaluation purposes. Overall, the influence of the employed numerical schemes in both equations is shown to be significant on computational meshes that are typically employed in the context of fire simulations. As expected, the discretization errors diminish when sufficiently fine grid resolutions are considered. The native schemes of OpenFOAM, filteredLinear2 and limitedLinear, are found to be relatively accurate, when compared to other numerical schemes in the literature: while maintaining boundedness of the solution, they introduce only small amounts of numerical dissipation

Proceedings of the first workshop organized by the IAFSS Working Group on Measurement and Computation of Fire Phenomena (MaCFP)

This paper provides a report of the discussions held at the first workshop on Measurement and Computation of Fire Phenomena (MaCFP) on June 10-11 2017. The first MaCFP workshop was both a technical meeting for the gas phase subgroup and a planning meeting for the condensed phase subgroup. The gas phase subgroup reported on a first suite of experimental-computational comparisons corresponding to an initial list of target experiments. The initial list of target experiments identifies a series of benchmark configurations with databases deemed suitable for validation of fire models based on a Computational Fluid Dynamics approach. The simulations presented at the first MaCFP workshop feature fine grid resolution at the millimeter- or centimeter-scale: these simulations allow an evaluation of the performance of fire models under high-resolution conditions in which the impact of numerical errors is reduced and many of the discrepancies between experimental data and computational results may be attributed to modeling errors. The experimental-computational comparisons are archived on the MaCFP repository [1]. Furthermore, the condensed phase subgroup presented a review of the main issues associated with measurements and modeling of pyrolysis phenomena. Overall, the first workshop provided an illustration of the potential of MaCFP in providing a response to the general need for greater levels of integration and coordination in fire research, and specifically to the particular needs of model validation