Imaging of unsteady separated flows: global interpretation with particle image velocimetry

Quantitative characterization of unsteady, separated flows is central to un derstanding the physics of flow-structure interactions, which can give rise to vibration and noise generation. Global, instantaneous representations, obtained from high-image-density particle image velocimetry, can provide a basis for identification and classification of flow patterns. Moreover, the se representations allow direct links to established theoretical concepts, which can be expressed in terms of vorticity. Case studies of vortex-domina ted flows are addressed using these approaches, with the aim of defining ch allenges and future prospects.