Experimental Comparison between the Flow Field of Two Common Fluidic Oscillator Designs

The time-resolved natural flow field of a fluidic oscillator

“…If the shape of the mixing chamber walls is more streamlined so that no initial separation bubble is present, the fluid from the feedback channels just pushes in between the main jet and the wall to deflect it to the opposite side (Ostermann et al 2015b). Besides the described switching mechanism, a few additional dynamics are noteworthy.…”

“…Therefore, this part of the nozzle may be omitted which may be beneficial for some applications. However, a smaller divergence angle may force the jet to attach to this wall and thereby increase the jet's maximum deflection (Ostermann et al 2015b). Some initial alterations of the nozzle geometry were also investigated by Bobusch et al (2013b).…”

Spectral proper orthogonal decomposition

“…These devices are used for active flow control applications, where the sweeping motion of the jet allows a much wider actuator spacing, resulting in less energy consumption (Woszidlo et al 2014). The data presented here stem from an experimental set-up investigating the spreading and entrainment of sweeping jets (Ostermann et al 2015b;Woszidlo et al 2015). The data are recorded at a Reynolds number of 37 000 based on the nozzle diameter D and the mean velocity in the nozzle.…”

Analysis of the Forces Driving the Oscillations in 3D Fluidic Oscillators

“…The peak to peak stagnation pressure fluctuations increase with increasing Reynolds number, and so does the pressure momentum term acting onto the mixing chamber inlet incoming jet.Original fluidic oscillators design goes back to the 60 s and 70 s. Their outlet frequency ranges from several Hz to KHz and the flow rate is usually of a few dm 3 /min. From their applications in flow control, it is interesting to mention their use in combustion control [3], flow deflection and mixing enhancement [4], flow separation modification in airfoils [5], boundary layer modification on hump diffusers used in turbomachinery [6], flow separation control on compressors stator vanes [7], gas turbine cooling [8], drag reduction on lorries [9], and noise reduction in cavities [10].Despite the existence of particular fluidic oscillator configurations, like the one introduced by Uzol and Camci [11], which was based on two elliptical cross-sections placed transversally and an afterbody located in front of them, or the one proposed by Huang and Chang [12], which was a V-shaped fluidic oscillator, most of the recent studies on oscillators focused on two main, very similar, canonical geometries, which Ostermann et al [13] called the angled and the curved oscillator geometries. Some very recent studies on the angled geometry are [13][14][15][16][17][18][19][20][21][22][23], while the curved geometry was studied by [4,10,13,[23][24][25][26][27][28][29][30][31][32][33].…”