Energy exchange in the transitional flow over bluff bodies*

Transition behavior of separating shear layers on sharp edged bodies has been shown to rely heavily on the freestream Reynolds number. In contrast, many parameters investigated in the wake demonstrate an approximate invariance with respect to Reynolds number (e.g., the Strouhal number for a 2D square prism). The apparent attenuation of Reynolds number influence on transitioning shear layers between leading and trailing edges is examined in the current study from a phenomenological perspective on a series of rectangular sections and angles of attack. PIV and hot wire techniques were used in pursuit of identifying and tracking the energetic scales in the flow and their spatio-temporal migration. Results reveal the severity of coupling between the two regions of instability and subsequent consequences for aerodynamic loading.