The objective of this experimental study is to attenuate the vortex shedding and recover the mean base pressure of a blunt trailing edge profiled body using modulated and unmodulated high-frequency forcing from an array of synthetic jets distributed near the trailing edge. The effect of the forcing amplitude, as well as the frequency and symmetry of the modulated forcing, is investigated on the wake at a Reynolds number of 2,500. Particle image velocimetry and hot-wire anemometry are used to quantify the impact of forcing on the recirculation region of the wake, the evolution of the separated shear layers, and the vortex street in planes directly behind the jets and in-between the jets. At a sufficient forcing amplitude in the unmodulated cases, the disorganization and spanwise breakup of the vortex street is observed, with weaker vortex shedding between the jets, and nearly complete decimation of the vortex street behind the jets. This is associated with a significant recovery of base pressure and a reduction of the velocity fluctuations in the wake. Using modulation over a range of frequencies from an order of magnitude less than the shedding frequency to greater than an order of magnitude above the shedding frequency, comparable base pressure recoveries to unmodulated forcing at the same amplitude are measured, indicating that modulation can be employed to improve the efficiency.
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