Numerical experiments by Large-Eddy Simulation (LES) are performed on the turbulent flow and mixing of a passive scalar past a square cylinder. A Reynolds number of 21 400 is selected, matching available flow measurements from laser-doppler velocimetry (LDV), and the scalar released from a point source downstream of the cylinder. A comparative study of numerical results against LDV data is presented in order to validate the present LES methodology, where sub-grid turbulent stresses are estimated via the WALE similarity mixed model coupled with newly developed constrained filtering operators of arbitrary order and scalar fluxes approximated via the Reynolds analogy. Time-averaged and phase-averaged statistics for the scalar field, including scalar variance and scalar flux components, are computed to examine further the role of coherent fluctuations associated with large-scale structures on the mixing process and to establish a database for turbulence models development and validation.
展开▼
