Comparative study of DNS, LES and Hybrid LES/RANS of turbulent boundary layer over 2d hill

摘要

This paper presents evaluations for the prediction accuracy of various SGS models of LES under the simple condition of urban environment, i.e., various thermally-stratified turbulent boundary layers are calculated by evaluated LES models, namely, the Smagorinsky and the Mixed-Time-Scale models, the representative SGS model for the velocity field, and the constant turbulent Prandtl number model for the thermal field. These models are evaluated in comparison with a DNS database, in which the problems of LES in the prediction of various thermally-stratified boundary layers are elucidated. On the other hand, in order to evaluate the prediction accuracy of various models in a complicated turbulent flow field, the LES and the hybrid LES/RANS (HLR) models are examined in a turbulent boundary layer over a 2-dimensional hill. These results are assessed using newly-conducted DNS results of a 2-dimensional hill, and the prediction accuracy of these models is clarified in the calculation of a complicated turbulent flow field.