While the phenomenon of stall is well-known (and feared) it remains a difficult issue in aerodynamics, and its accurate prediction is only possible by means of experiments in wind tunnels.
Zonal Detached-Eddy Simulation (ZDES) of the flow around a 3D wing of finite span in stalled configuration by the elsA software
[computation by François Richez, Michel Costes, Robert Gaveriaux, "Helicopters, Propellers, Turbomachine" unit of the Applied Aerodynamics Department]
But in 2010 the Onera aerodynamicists performed a simulation of stall with the elsA software using the computation resources of the GENCI (National High Performance Computing Facility). This type of simulation on a 3D wing was a first for Onera: 2,600,000 hours CPU hours on 1024 processors, with a grid of 150 million points.
The numerical results are in very good agreement with the experiment. The average velocity fields provided by this simulation agree with the measurements by particle image velocimetry (PIV).
A more in-depth analysis of the unsteady pressure signals is going to be conducted in order to identify the instability mechanisms that characterize this type of complex flow.