NUMERICAL WAKE VISUALIZATION FOR AIRFOILS UNDERGOING FORCED AND AEROELASTIC MOTIONS

A virtual wind tunnel is developed by combin-ing a fast, time-stepping ow solver with an interac-tive animation interface. Inviscid, incompressible ow solutions are provided by an unsteady, potential- ow code with arbitrary airfoils undergoing forced or aeroe-lastic motions. Aeroelastic response is predicted by a two-degree-of-freedom spring/mass system modeling the structural dynamics of a exible wing. A bound-ary layer code may be used to predict viscous ow eects such as transition and the onset of ow sepa-ration. The aeroelastic algorithm is coupled with an interactive graphical animation front end, enabling vi-sualization and measurement of the unsteady wake and surrounding ow eld. To further enhance the virtual wind tunnel look and feel, an assortment of tools is provided to mimic smoke/dye-injection, wake-vorticity tagging and ow anemometry. The complete package is used both as a research and an instructional tool, providing insight into the complex, unsteady vortical structures behind moving airfoils. Solutions compare well with experimental data while the animationallows a more thorough investigation of the development and evolution of the wake structures in time. Nomenclature A = plunge amplitude in terms of c c = chord length C d = drag coecient per unit span, D=(