Characterization of inclined oscillating jets and crossflow interaction for use in active flow control

Flow Control, Fluidic Oscillators, inlination angle, blowing ratio, sPIV, Momentum addition, Vortex generation

Awate, Vanessa Ghislaine ; Ansell ; Phillip J

关键词: Flow Control, Fluidic Oscillators, inlination angle, blowing ratio, sPIV, Momentum addition, Vortex generation;   

Others  :  https://www.ideals.illinois.edu/bitstream/handle/2142/108023/AWATE-THESIS-2020.pdf?sequence=1&isAllowed=y

美国|英语

来源: The Illinois Digital Environment for Access to Learning and Scholarship

【 摘 要 】

Phase-locked stereoscopic PIV measurements were conducted to understand the interaction of inclined fluidic oscillator jets with a crossflow across a range of different blowing ratios. The fluidic oscillators used in the current study featured rounded internal feedback channels and produced spatially oscillating jets at predictable frequencies.When integrated into aerodynamic bodies, fluidic oscillators have the potential to re-energize boundary layers and delay the onset of flow separation at high angles of attack. Understanding the effects of blowing ratios and inclination angles on mixing characteristics and turbulent interactions in the flow can shed light on the effectiveness of such fluidic oscillators for active flow control purposes. Fluidic oscillators with an aspect ratio of 2 and inclination angles of 30°, 60° and 90° were designed and tested at different mass flow rates through the jet for a given freestream condition. The variation in the subsequent interactions produced with varying jet velocity and inclination angle, relative to the crossflow, were considered.For the investigated blowing ratios, the development and convection of high momentum regions and vortices were observed across the flow field. For higher blowing ratios, the downstream propagation of these structures was accompanied by larger spanwise and wall-normal jet penetration into the boundary layer due to higher turbulence interactions. Preliminary results for inclination angles of 60° and 90° revealed that the inclination angle affected the formation of vortices in the flow field and suggested that a combination of blowing ratio 5 and inclination angle of60° would be an appropriate starting point for active flow control with fluidic oscillators.