Impact of orifice orientation on a finite-span synthetic jet interaction with a crossflow

Buren, Tyler Van; Leong, Chia Min; Whalen, Edward A.; Amitay, Michael

doi:10.1063/1.4943520

Cited by 25 publications

(27 citation statements)

References 18 publications

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“…In addition, the virtual blockage of the jet was reduced with the decreased AR. In another similar study, Van Buren et al (2016 b ) investigated the orifice orientation with pitch (20°−90°) and skew (0°−90°) angles on the vortex formation of an AR = 18 rectangular orifice. Three types of scenarios, i.e.…”

Section: Introductionmentioning

confidence: 99%

The interactions of rectangular synthetic jets with a laminar cross-flow

Wang

Feng

2020

J. Fluid Mech.

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Section: Introductionmentioning

confidence: 99%

The interactions of rectangular synthetic jets with a laminar cross-flow

Wang

Feng

2020

J. Fluid Mech.

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“…and Amitay, 2006, Travnicek et al 2011, McGuinn et al 2013 and in mixing enhancement (Freund andMoin 2000, Al-Atabi 2011). The applications of synthetic jets in cross-flow have also been reported in boundary layer control and drag reduction (Lardeau et al 2011, Laouedj et al 2015, Buren and Leong 2016, Kumar and Karn 2018.…”

Section: Introductionmentioning

confidence: 99%

The effect of a parallel free surface upon a submerged shallow synthetic jet

et al. 2020

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The interaction of a submerged shallow synthetic jet with a parallel free surface has gathered substantial interest, owing to its relevance to the operation of marine vehicles viz. ships that move close to the water surface. However, despite exhaustive research on the perturbation on a free surface, very few studies have experimentally investigated the effect of unconfined water surface height on the evolution and propagation of a submerged synthetic jet. This study experimentally investigates a synthetic jet submerged in a quiescent flow at shallow depths ejecting parallel to the free surface, through qualitative analysis and quantitative measurements. The qualitative study includes the visualization of the flow using Plane Laser Induced Fluorescence (PLIF) technique, whereas the velocity measurements are carried out by a five-beam Laser Doppler Velocimetry (LDV) probe. The primary objective of these analysis and measurements is to gain a physical insight into the characteristics of vortex ring in a synthetic jet ejected from a fixed orifice at different water depths and at varying Reynolds number. Our studies indicate that the behavior of the vortex rings drastically changes as the depth of the jet crosses a certain threshold. Although no significant change in the path of synthetic jet is observed beyond a threshold depth in our experiments, the jet trajectory shows an interesting dependence on the Reynolds number based on circulation for shallow water depths. It has been found that in the shallow depths, the vortex ring drifts upwards and interacts with the free surface at lower Reynolds number, whereas for larger Reynolds number, the vortex ring rebounds near the free surface and moves downward. Based on our observations, it can be concluded that the phenomenon of upward/downward flection of vortex rings depends both upon its circulation and water depth.

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“…The current work expands on that study by increasing the reduced frequency to values expected on the CART3 turbine, using its associated airfoil, by pitching into both shallow and deep stall, and by utilizing more advanced synthetic jet technology including a pitched orifice with higher flow velocities. A further description of the mechanisms by which synthetic jets add momentum and vorticity into the flow is detailed in Glezer and Amitay, Van Buren et al, and Sahni et al The strength of an array of synthetic jets is described by the momentum coefficient, C μ , which is the ratio of momentum injected during the outsroke of the synthetic jet to the momentum of flow over the airfoil, given by

C_{μ} = \frac{n \overset{I_{j}}{true}}{\frac{1}{2} ρ_{\infty} U_{\infty}^{2} S},

where n is the number of active synthetic jets, and

\overset{I_{j}}{true}

is the time‐averaged synthetic jet momentum during outstroke and can be written as

\overset{I_{j}}{true} = \frac{1}{τ} ρ A_{s j} \int_{0}^{true τ} u_{s j}^{2} false(t false) d t .

…”

Section: Introductionmentioning

confidence: 99%

Wind tunnel quantification of dynamic stall on an S817 airfoil and its control using synthetic jet actuators

2018

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Wind tunnel experiments were performed to quantify the aerodynamic characteristics of the S817 airfoil in dynamic stall conditions, and the subsequent application of active flow control to modify the manner by which dynamic stall incepts. Both quasi‐2D and cantilevered finite span configurations were tested. Surface pressure, six‐component force‐torque sensor, and stereoscopic particle image velocimetry (SPIV) were used to quantify the baseline flow and the benefits of actuating synthetic jets (installed at x/c = 0.35, angled 45° into the flow, and at a momentum coefficient Cμ = 0.012). The airfoil was pitched at reduced frequencies of kf = 0.025 and 0.05 and at shallow and deep stall. Vortex induced lift from dynamic stall was observed and was eliminated by the use of synthetic jets for nearly all conditions; pitching moment deviation was also observed to be significant, and was eliminated at shallow stall and significantly reduced during deep dynamic stall when the synthetic jets were actuated. Moreover, the activation of synthetic jets resulted in significant reduction in the hysteresis (area within the pitching up and pitching down load history) of the lift and pitching moment through all experimental conditions, as much as 41% and 85%, respectively. SPIV flow fields in shallow dynamic stall demonstrated that actuation of synthetic jets confined the separated region to the trailing edge, in both the instantaneous and time averaged sense. To further reduce the lift and pitching moment hysteresis at high angles of attack, a pulse modulation technique was used and showed a marked increase in synthetic jet performance compared with the continuously actuated case and achieved this result with approximately 65% less power consumption.

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Impact of orifice orientation on a finite-span synthetic jet interaction with a crossflow

Cited by 25 publications

References 18 publications

The interactions of rectangular synthetic jets with a laminar cross-flow

The interactions of rectangular synthetic jets with a laminar cross-flow

The effect of a parallel free surface upon a submerged shallow synthetic jet

Wind tunnel quantification of dynamic stall on an S817 airfoil and its control using synthetic jet actuators

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