Multi-component - Multi-dimensional PIV measurements of low Reynolds number flow around flat plate undergoing pitch-ramp motion

High-rate low Reynolds number unsteady aerodynamics is experimentally investigated with a flat plate undergoing pitch-ramp motion at a Reynolds number Re_c ≈ 7500. The experiments are conducted in a water tunnel where phase-triggered instantaneous 3 component - 2 dimensional (3C-2D) stereoscopic PIV (SPIV) measurements were carried out. The phase-triggered realizations were averaged to yield ensemble averaged 3C-2D SPIV which provided the evolution of the 3C-2D velocity field during the pitch-ramp motion. The evolution of both the leading and trailing edge vortices are revealed by the ensemble averaged vorticity field at the five discrete time steps during the ramp-hold-return motion sequence.