Recent developments in delta wing aerodynamics

Recent developments in delta wing aerodynamics are reviewed. For slender delta wings, recent investigations shed more light oil the unsteady aspects of shear-layer structure, vortex core, breakdown and its instabilities. For nonslender delta wings, Substantial differences in the structure of vortical flow and breakdown may exist. Vortex interactions are generic to both slender and nonslender wings. Various unsteady flow phenomena may cause buffeting Of wings and fins, however, vortex breakdown, vortex shedding, and shear layer reattachment are the most dominant Sources. Dynamic response of vortex breakdown over delta wings in unsteady flows can be characterised by large time lags and hysteresis, whose physical mechanisms need further studies. Unusual flow-structure interactions for nonslender wings in the form of self-excited roll oscillations have been observed. Recent experiments showed that substantial lift enhancement is possible on a flexible delta wing.