The turbulence modelling of a pulsed impinging jet using LES and a divergence free mass flux corrected turbulent inlet

Abstract This paper examines the best turbulence model to use when using computational fluid dynamics to simulate an impinging jet type flow. The IDDES, k- ω SST SAS, Smagorinsky and dynamic Smagorinsky models were used and compared to data collected from a laboratory impinging jet, developed to simulate thunderstorm downburst flow fields. From this it was found the dynamic Smagorinsky model performed best, especially at capturing the velocities and pressures in the near inlet region. A mesh dependency study was then performed for the dynamic Smagorinsky turbulence model. A small mesh dependency was demonstrated for the mesh densities studied but had issues in capturing the velocity height profile correctly in the near wall region. Despite this issue the model still closely matched the laboratory pressures around a 60 m m cube and demonstrated the suitability of this modelling approach for investigating thunderstorm downbursts.