DOI: 10.1615/ICHMT.2012.ProcSevIntSympTurbHeatTransfPal
ISBN Print: 978-1-56700-302-4
ISSN: 2377-2816
RANS-based numerical simulation of a rectangular turbulent jet in crossflow
SINOPSIS
Steady Reynolds-Averaged Navier-Stokes (RANS) modelling using a commercially available computational fluid dynamics (CFD) package ANSYS-CFX has been applied to investigate flow characteristics of a fully-developed turbulent jet flow in a rectangular duct being issued perpendicularly into a crossflow field. This follows a previous case being studied by using a large-eddy simulation (LES) approach. Specific attention is brought to the RANS simulations of the jet to crossflow velocity ratios of 3.3, 5, 7.3, 8 and 10, respectively and Reynolds number of 26,000, based on the jet bulk velocity and jet width. Numerical issues such as grid resolution, boundary condition choices and turbulence model influences have been addressed, together with assessment of the reliability of eddy-viscosity based models in predicting turbulent flow of this configuration; e.g. three two-equation turbulence models k-ε, k-ω and SST. Comparison of the present steady RANS calculations with the previous 'mean' profiles obtained by LES study at several streamwise locations are found in good agreement when using both k-ε and SST models. Whereas, RANS results from the k-ω model is unable to predict these 'mean' quantities accurately. Furthermore, all three turbulence models are unable to predict the second-order statistics, such as turbulent kinetic energy. This means that a proper prediction of these high-order statistics for a configuration like jet in crossflow does require higher spatial and temporal resolution scheme that is able to re-produce the inherent dynamic flow mixing process.