Computational Methods for High Lift

Inviscid Methods

Three-dimensional high-lift systems with large vortex drag can be computed quite well with some efficient panel methods (VSAERO, for example). When flow separation become a non-negligible effect, and the viscous effects must be accounted for (presence of cove areas, blunt edges, high angle of attack, wakes interactions, strong spanwise pressure gradients, etc.), then there is a need for more sophisticated calculations.

Among the viscous-inviscid techniques used in two- dimensional flows there is the code MSES (Drela, 1991) and the older NASA code MCARF (Brune-Manke, 1978). The method of Le Balleur (Le Balleur, 1992), can be used for both airfoils and wings at transonic speeds with relatively high angles of attack.

Navier-Stokes methods include both unstructured and structured approaches. These methods are more time consuming, and have been applied essentially to two- dimensional configurations, although three-dimensional wings are being treated. However, the literature in this field is a phase of continuous update.

The problem of computing CLmax is one of formidable difficulty that has not been solved satisfactorily even for single element airfoils. Among the problems that must be overcome is the modeling of turbulence and the separated flow past the stalling point. Drag characteristics, that are nearly as important, are also very difficult to predict.