Experimental and numerical study on flow characteristics and heat transfer of an oscillating jet in a channel

Mohammadshahi, Shabnam; Samsam-Khayani, Hadi; Cai, Tao; Kim, Kyung Chun

doi:10.1016/j.ijheatfluidflow.2020.108701

Cited by 29 publications

(13 citation statements)

References 38 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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“…The accuracy of the employed PIV algorithm has been previously exstensively assessed in literature (e.g., Guérin et al (2020), Vennemann and Rösgen (2020), Mohammadshahi et al (2020), Narayan et al (2020)). However, in order to ensure the physical consistency of our PIV measurements, two benchmark cases are here presented.…”

Section: Assessment Of Piv Chain Analysismentioning

confidence: 99%

A new dynamic masking technique for time resolved PIV analysis

Lombardi

Rocca

Prestininzi

2021

J Vis

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Time resolved PIV encompassing moving and/or deformable objects interfering with the light source requires the employment of dynamic masking (DM). A few DM techniques have been recently developed, mainly in microfluidics and multiphase flows fields. Most of them require ad-hoc design of the experimental setup, and may spoil the accuracy of the resulting PIV analysis. A new DM technique is here presented which envisages, along with a dedicated masking algorithm, the employment of fluorescent coating to allow for accurate tracking of the object. We show results from measurements obtained through a validated PIV setup demonstrating the need to include a DM step even for objects featuring limited displacements. We compare the proposed algorithm with both a no-masking and a static masking solution. In the framework of developing low cost, flexible and accurate PIV setups, the proposed algorithm is made available through a freeware application able to generate masks to be used by an existing, freeware PIV analysis package. Graphic abstract

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“…It was shown that in the internal domain, the sweeping jet flow depends on parameters of a fluidic oscillator such as geometric ratios, number, and parameters of feedback channel, the diverging angle of a throat, a rate of mass flow on the inlet of the oscillator. The influence of the geometry of the external domain on the structure and dynamics of a sweeping jet flow was studied in works [18][19][20][21][22][23]. It was shown in [15] that vortex structures formed at the maximum deflection of the jet could affect the structure and dynamics of the oscillating jet.…”

Section: Introductionmentioning

confidence: 99%

“…It was shown in [15] that vortex structures formed at the maximum deflection of the jet could affect the structure and dynamics of the oscillating jet. The study of the influence of the confined external domain on the dynamics and structure of the flow of an oscillating jet was carried out in [21][22][23]. The authors of the study [22] showed that for the external domain, there is the range of Re numbers when oscillations of a sweeping jet are discontinued as a result of the attachment of the jet when the deflection angle is maximum.…”

Section: Introductionmentioning

confidence: 99%

Experimental study of flow dynamics of a sweeping jet in a slot channel

Shestakov

2021

J. Phys.: Conf. Ser.

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In recent years, fluidic oscillators have been actively applied as devices for flow control in the field of aero and hydrodynamics. This study aims to investigate the structure of a flow of sweeping jet ejected from a fluidic oscillator into a confined area – slot channel. Dynamics of sweeping jet flow are investigated using the PIV method with high temporal resolution. The effect of the Re number on the sweeping jet oscillation frequency was studied in the range from 1 500 to 8 000. Linear frequency dependence on Re number was obtained. Bounding walls affect the dynamics of sweeping jet flow that leads to a change of average velocity field. For low Re numbers, obtained results are in good agreement with the results of other studies.

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Experimental and numerical study on flow characteristics and heat transfer of an oscillating jet in a channel

Cited by 29 publications

References 38 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

A new dynamic masking technique for time resolved PIV analysis

Experimental study of flow dynamics of a sweeping jet in a slot channel

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