DNS database of a transitional separation bubble on a flat plate and application to RANS modeling validation

The present study consists in an analysis of the DNS database of a flow overcoming a transitional separation induced by an adverse pressure gradient on a flat plate under a curved upper wall. This study takes place in the context of improving RANS models for the simulation of the stall phenomenon for rotor blades applications. To mimic the real flow mechanisms, the flow characteristics are chosen to be typical of the leading edge of the OA209 airfoil at an incidence just below stall occurence: 15° of incidence, Rc∞=1.8×106Rc∞=1.8×106 and M∞=0.16M∞=0.16. The budgets of the turbulent kinetic energy transport equations have been computed by the DNS. Their evolution is analysed from the separation up to the downstream turbulent flow. Comparisons with a URANS k–ω Wilcox computation are presented to illustrate the application of the DNS simulation.

► Airfoil stall phenomenon due to laminar separation bubble (LSB). ► DNS of a short transitional separation bubble on a flat plate with Rtheta up to 1800. ► DNS database includes budgets of the turbulent kinetic energy transport equations. ► Evaluation of the RANS modeling of transition with LSB. ► Assessment of the k–ω Wilcox RANS model with different intermittency functions.