DOI: 10.1615/TSFP6
NUMERICAL STUDIES OF A HIGHLY ANISOTROPIC RECIRCULATION BUBBLE IN A THIN FLAT PLATE AT SMALL ANGLE OF ATTACK
Краткое описание
One of the situations that evidences some fundamental weakness of Reynolds Average Navier Stokes (RANS) approach to turbulence modeling is that involving highly anisotropic turbulence structures, such as that observed in long and thin recirculation zone in a high Reynolds number aerodynamic flow. Previous numerical studies tried to reproduce the experimental results from Crompton (2001) for a leading-edge separation in a thin flat plate at small incidence, using several RANS models. None of these models proved to be able of capturing some very important features of this flow, and it was suggested that Large-Eddy Simulations would not only provide more accurate results, but also allow a better physical understanding of the turbulence mechanisms. Therefore, in this work Large-Eddy Simulations is employed to determine the flow field over a thin flat plate, and results are compared with experimental data from Crompton (2001), with two completely different approaches for subgrid modeling: the traditional Dynamic Smagorinsky model from Germano (1999), and a new one, based on an advective forcing approach (Sampaio et al, 2007). Both approaches showed a very good agreement with the experimental data, and were able to capture all the important structures, such as boundary layer separation and reattachment, relaminarization, primary and secondary recirculation zones, and fast shear layer transition.