A PIV Study of Synthetic Jets with Different Orifice Shape and Orientation

Zhong, Shan; Garcillan, Luis; Pokusevski, Z.; Wood, N. J.

doi:10.2514/6.2004-2213

Cited by 20 publications

(14 citation statements)

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“…With the aid of Direct Numerical Simulation (DNS), Ravi et al [44] ). Their results revealed that the axis switching behaviour had grown vigorously at increased aspect ratio, which is in agreement with the experimental results of Garcillan et al [41]. In addition, they also found that an increased aspect ratio had led to a more parabolic normalized jet exit velocity profile during expulsion and ingestion phases, although with no notable change in the peak value.…”

Section: Please Cite This Article As Doi:101063/15142408supporting

confidence: 89%

“…This phenomenon is termed 'axis switching' due to the fact that the locations of the short and long axes will switch with each other after a certain downstream distance. Axis switching is regarded as the main mechanism responsible for enhancing the mixing in both continuous jets [38]- [40] and synthetic jets [41], [42]. Nevertheless, several studies have found that a change in the aspect ratio of the slotted orifice can alter the axis-switching behaviour and affect the jet velocity.…”

Section: Effect Of Aspect Ratio On Axis-switching Behaviour and Flow ...mentioning

confidence: 99%

“…However, the online version of record will be different from this version once it has been copyedited and typeset. Garcillan et al [41] conducted an experimental investigation to examine the effect of the aspect ratio of a slotted orifice on the jet flow in a quiescent condition by utilizing the SJA rig of Crook et al [43]. The jets issuing from orifices with aspect ratios of AR = 1, 5, 10 and 16 were compared, while the cavity geometry and orifice exit area were held as constant.…”

Section: Effect Of Aspect Ratio On Axis-switching Behaviour and Flow ...mentioning

confidence: 99%

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Effect of geometric parameters on synthetic jet: A review

2020

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A synthetic jet actuator is a fluidic device that produces a jet flow by the periodic ingestion of fluid into and expulsion of fluid out of a cavity across an orifice. Since such a mechanism transfers linear momentum to the fluid without introducing a net mass into the system over an actuation cycle, the synthesised jet is also termed a zero-net-mass-flux jet. Over the last two decades, synthetic jets have been the subject of intense research. It has been shown that the geometric parameters of a synthetic jet actuator can strongly influence the flow characteristics and performance of synthetic jets. The aim of this paper is to provide a comprehensive review of the influence of the geometric parameters of a synthetic jet actuator on the characteristics

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Section: Please Cite This Article As Doi:101063/15142408supporting

confidence: 89%

Section: Effect Of Aspect Ratio On Axis-switching Behaviour and Flow ...mentioning

confidence: 99%

Section: Effect Of Aspect Ratio On Axis-switching Behaviour and Flow ...mentioning

confidence: 99%

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Effect of geometric parameters on synthetic jet: A review

2020

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“…Wu and Leschziner used LES (with dynamic subgrid scale model of Germano and Lilly as mentioned in Reference and smoothing of dynamic global coefficient), 7.3 ×10 6 cells in a large domain size, and an incoming turbulent boundary layer generated with the rescaling method proposed by Lund et al . They compared quantitatively and qualitatively the LES results with the experimental data compiled by Garcillan and confirmed that the synthetic jet injection is capable of modifying the global behavior of a turbulent boundary layer at scales that are significantly larger than the jet itself. They also presented the shear stress as the main agency for the transfer of mean momentum by turbulent motions.…”

Section: Introductionmentioning

confidence: 81%

Numerical prediction of turbulent flow structure generated by a synthetic cross‐jet into a turbulent boundary layer

Javadi

El‐Askary

2011

Numerical Methods in Fluids

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SUMMARY A detailed numerical study using large‐eddy simulation (LES) and unsteady Reynolds‐averaged Navier–Stokes (URANS) was undertaken to investigate physical processes that are engendered in the injection of a circular synthetic (zero‐net mass flux) jet in a zero pressure gradient turbulent boundary layer. A complementary study was carried out and was verified by comparisons with the available experimental data that were obtained at corresponding conditions with the aim of achieving an improved understanding of fluid dynamics of the studied processes. The computations were conducted by OpenFOAM C++, and the physical realism of the incoming turbulent boundary layer was secured by employing random field generation algorithm. The cavity was computed with a sinusoidal transpiration boundary condition on its floor. The results from URANS computation and LES were compared and described qualitatively and quantitatively. There is a particular interest for acquiring the turbulent structures from the present numerical data. The numerical methods can capture vortical structures including a hairpin (primary) vortex and secondary structures. However, the present computations confirmed that URANS and LES are capable of predicting current flow field with a more detailed structure presented by LES data as expected. Copyright © 2011 John Wiley & Sons, Ltd.

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“…Jets behavior is highly influenced by geometrical parameters such as, aspect ratio (AR). A slotted jet can affect jet velocity, enhance axis switching phenomena while the AR increases, therefore, increasing jet velocity [13]; AR can affect vortex formation and the jet centerline velocity [14]. Cavity dimensions, such as height, can also affect induced velocity.…”

Section: Introductionmentioning

confidence: 99%

Towards Accurate Boundary Conditions for CFD Models of Synthetic Jets in Quiescent Flow

Matiz-Chicacausa

Mejia

2020

Energies

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In this paper, an accurate model to simulate the dynamics of the flow of synthetic jets (SJ) in quiescent flow is proposed. Computational modeling is an effective approach to understand the physics involved in these devices, commonly used in active flow control for several reasons. For example, SJ actuators are small; hence, it is difficult to experimentally measure pressure changes within the cavity. Although computational modeling is an advantageous approach, experiments are still the main technique employed in the study of SJs due to the lack of accurate computational models. The same aspect that represents an advantage over other techniques also represents a challenge for the computational simulations, such as capturing the unsteady phenomena, localized compressible effects, and boundary layer formation characteristic of this complex flow. One of the main challenges in the simulation of SJs is related to the fact that the spatial and temporal scales of the actuator and the corresponding flow control application differed in several orders of magnitude. Hence, in this study we focus on the use of Computational Fluid Dynamics (CFD) and Reduced Order Models (ROM) to develop an accurate yet low-cost model to capture the complexities of the flow of a SJ in quiescent flow. Numerical results show two possible paths for SJ modeling; (1) to obtain a boundary condition to predict velocity profile and jet formation from experimental data of diaphragm’s deformation; and, (2) to predict peak velocity at the jet’s outlet with a ROM approach and to use the physical details of the actuator to develop an accurate boundary condition for CFD. Both approaches are validated through experimental data available in the literature; good agreement between results from CFD, Lumped Element Model (LEM), and experimental data are achieved. Finally, it was concluded that the coupling between LEM and CFD is a novel and accurate approach, which improves CFD due to the advantages of LEM closing the gap between LEM’s lack of flow detail and CFD’s lack of geometrical/physical information of the actuator.

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A PIV Study of Synthetic Jets with Different Orifice Shape and Orientation

Cited by 20 publications

References 3 publications

Effect of geometric parameters on synthetic jet: A review

Effect of geometric parameters on synthetic jet: A review

Numerical prediction of turbulent flow structure generated by a synthetic cross‐jet into a turbulent boundary layer

Towards Accurate Boundary Conditions for CFD Models of Synthetic Jets in Quiescent Flow

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