Flow Physics and Scaling for Discrete Jet Forcing on a Wall-Mounted Hump

An experimental study is conducted to explore flow physics and scaling parameters (e.g., aspect ratio, exit area, spacing) for various types of fluidic oscillators in support of the development of active flow control technology. Various actuation modules are tested on the NASA hump geometry. Experiments are carried out at a chord-based Reynolds numbers of 1.0 x 10⁶ (Ma = 0.09). Time-averaged pressure is measured along both the chord and span of the model. Stereoscopic PIV is performed downstream of the actuation location to investigate the underlying control mechanisms in detail. Separation control using various spatially distributed fluidic oscillators is tested with spacings of Δz/c = 2.27%, 4.55%, 6.82%, & 9.09%. Performance curves are generated based on a novel method to experimentally obtain the momentum coefficient. These curves reveal regions of different efficiency and can be associated with boundary layer and circulation control depending on their slope. Stereoscopic PIV data is used to connect the mean and unsteady flow structure to separation control efficacy using various data analysis techniques.