Intermittent round jet controlled by lateral pulse-modulated synthetic jets

Broučková, Zuzana; Trávníček, Z.

doi:10.1007/s12650-019-00550-z

Cited by 11 publications

(3 citation statements)

References 35 publications

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“…Therefore, an oscillating jet is emitted to the external domain, without using mechanical parts. In recent decades, this type of fluidic oscillator attracted much research interest and is used in various applications, like heat transfer enhancement [10][11][12][13][14][15][16], mixing enhancement [17][18][19][20][21], and separation control [22][23][24]. In the literature, it is alleged that the oscillation frequency of the jet is dependent on the internal region.…”

Section: Introductionmentioning

confidence: 99%

Experimental Study on Physical Behavior of Fluidic Oscillator in a Confined Cavity with Sudden Expansion

2020

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In this study, two-dimensional time-resolved particle image velocimetry (2D-TR-PIV) was used to investigate the effect of the external domain on oscillating jets from double-feedback fluidic oscillators. Two different cases with different Re numbers (2680–10,730), as free external domain and fully confined were studied. Time-averaged results showed although a self-oscillating jet was attained for the free external domain, it could not be achieved for a fully confined geometry. For a fully confined geometry at Re = 2680, two symmetric vortices did not allow the jet to oscillate and at Re = 6440, the flow pattern in the external region became non-symmetric due to the Coanda vortex, subsequently, the self-oscillating jet was not observed. At Re = 10,730, the strength of the jet was inclined to cope with such vortices and tended to oscillate. However, strong vortices were created near the exit region of the fluidic oscillator, which led to an almost non-symmetric pattern. In addition, the proper orthogonal decomposition (POD) method and phase-averaged analysis were applied to obtain the unsteady behavior of flow and the most energetic dynamic structure. Interestingly, at Re = 6440, the third mode was still energetic for fully confined, but for other cases, the first two modes were the most energetic modes, which showed vigorous coherent structures.

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Section: Introductionmentioning

confidence: 99%

Experimental Study on Physical Behavior of Fluidic Oscillator in a Confined Cavity with Sudden Expansion

2020

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“…Unlike the shear layer modes, which originate from shear layer instability, jet preferred modes are large-scale helical and axisymmetric structures that arise from jet global instability and with unstable frequency that scales with the jet diameter (Ball et al, 2012;Hussain and Zaman, 1981). This control mechanism benefits from low pressure drop compared with, for instance, the sweeping jet (Kim and Kim, 2019), and avoids complexity compared with active control methods (Broučková and Trávníček, 2019). Following the concept of our previous study (He et al, 2018), modification of the nozzle exit using lobed geometry would have a substantial effect on the formation of the jet preferred modes (Hussain and Zaman, 1981), which play a significant role in the jet-mixing characteristics and are of particular interest for a fundamental understanding of the flow dynamics.…”

Section: / 23mentioning

confidence: 99%

Dynamics of the jet flow issued from a lobed Nozzle: Tomographic particle image velocimetry measurements

Liu

Gan

2021

International Journal of Heat and Fluid Flow

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“…In previous studies, synthetic jets have been shown to alter the flow fields of free jets [25]- [27] to an experimentally significant degree. Perez, et al, [21], [22] applied a synthetic jet array to a wall jet nozzle and found that lower actuation frequencies (30 Hz, 60 Hz, and 120 Hz) enhanced the lateral width of the wall jet.…”

Section: Introductionmentioning

confidence: 97%

Synthetic Jet Development For Wall Jet Flow Control

Sim¹,

Ellis²,

Hall³

2021

Progress in Canadian Mechanical Engineering. Volume 4

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The design and construction of synthetic jet actuators for use in active flow control of a turbulent three-dimensional wall jet was investigated experimentally. Seven actuator designs of varying cavity depth and channel height were evaluated based on hot-wire velocity measurements, maximum RMS velocity outputs, and momentum coefficients. Initially, the synthetic jet actuators were driven with sinusoidal frequency sweeps from 10 Hz to 1510 Hz to identify frequencies associated with the strongest velocity output. For each actuator, momentum coefficients were calculated from sinusoidal inputs at the frequencies that produced the strongest jets. Evaluation of these tests showed that the most successful synthetic jet actuator had a cavity depth of 2 mm and channel height of 1.5 mm; it produced the strongest velocity output with momentum coefficients from 0.03-0.05 at input frequencies of 1100-1150 Hz. Synthetic jet actuators capable of providing these momentum coefficients have been shown from the literature to achieve flow control.Index Terms-Synthetic jets, active flow control, threedimensional wall jets, unsteady wall pressure

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Intermittent round jet controlled by lateral pulse-modulated synthetic jets

Cited by 11 publications

References 35 publications

Experimental Study on Physical Behavior of Fluidic Oscillator in a Confined Cavity with Sudden Expansion

Experimental Study on Physical Behavior of Fluidic Oscillator in a Confined Cavity with Sudden Expansion

Dynamics of the jet flow issued from a lobed Nozzle: Tomographic particle image velocimetry measurements

Synthetic Jet Development For Wall Jet Flow Control

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