Investigation of effects of compressibility, geometric and flow parameters on the simulation of a synthetic jet behaviour

Bazdidi–Tehrani, Farzad; Abouata, Ahmad; Hatami, M.; Bohlooli, Nima

doi:10.1017/aer.2016.8

Cited by 8 publications

(3 citation statements)

References 33 publications

(41 reference statements)

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“…Mallinson et al [15] and Mane et al [16] showed that a larger cavity height yields lower induced velocity while decreasing cavity height would produce the opposite effect. Bazdidi-Therani et al [17] agree with this observation in their computational study of a SJ flow in compressible regime using dynamic mesh for modeling the diaphragm deformation. Utturkar [18] observed that changes in the cavity aspect ratio have limited effect on the jet exit; concluding that details of cavity design and diaphragm placement do not have an important role in jet performance.…”

Section: Introductionsupporting

confidence: 64%

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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Section: Introductionsupporting

confidence: 64%

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

Matiz-Chicacausa

Mejia

2020

Energies

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“…Bazdidi et al [20] simulated a turbulent synthetic jet by two different technics for simulation of the actuator, namely, the mass flow inlet and the dynamic mesh method. They concluded that the compressible flow model presents more accurate results than the incompressible one.…”

Section: Introductionmentioning

confidence: 99%

“…While in some other researches, even with the same range of train velocity, [15,24,28,35,36] the flow is assumed to be compressible. It is good to note that when high-speed trains move at a velocity of around 300 km/h, the compressible flow was necessarily applied [13,20,29,37]. On the other hand, a computer program named subway environment simulation (SES) was widely used for simulating the air flow inside the tunnels.…”

Section: Introductionmentioning

confidence: 99%

Investigation of the effects of different parameters on the generated pressure waves inside the tunnels

et al. 2020

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In this research the train movement along the tunnel was simulated numerically, and the time evolution of the flow field in the tunnel was evaluated. The unsteady forms of continuity, Navier-Stokes, and energy equations were applied to solve the compressible viscous flow using the dynamic mesh technique. The importance of using a compressible flow model, even for the low Mach number flow case, was demonstrated. It was shown that even in low train speeds; a compressible model is preferred, as it can predict the pressure fluctuations, while an incompressible model may only be used for predicting the mean pressure. However, in cases where pressure fluctuations are not important, the incompressible model can be used especially for a train with low acceleration. When the trains accelerate, it was found that the initial slope of the pressure curve is proportional to the train acceleration. Therefore, the increase in the train acceleration increases the maximum pressure rise. Also, the first pressure rise depends on the velocity of the train tail as it enters the tunnel. In addition, the earlier equations in the literature for computing the maximum pressure rise, can properly predict the pressure rise of accelerating trains if the train tail velocity, as it enters the tunnel, is used as the velocity scale.

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Synthetic jet actuators: Overview and applications

Ja'fari,

Shojae,

Jaworski

2023

International Journal of Thermofluids

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Investigation of effects of compressibility, geometric and flow parameters on the simulation of a synthetic jet behaviour

Cited by 8 publications

References 33 publications

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

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

Investigation of the effects of different parameters on the generated pressure waves inside the tunnels

Synthetic jet actuators: Overview and applications

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