Contrôle par jet pulsé de l'écoulement dans un divergent court à grand angle

BenChiekh, Maher; Béra, Jean‐Christophe; Michard, Marc; Sunyach, M.

doi:10.1016/s1620-7742(00)01244-7

Cited by 7 publications

(5 citation statements)

References 5 publications

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“…The diffuser was designed such that injection could be introduced in the streamwise direction. Previous results obtained with cross-stream injection can be found in [4].…”

Section: Fluid Control In Diffusersmentioning

confidence: 99%

Synthetic jet control for flows in a diffuser: vectoring, spreading and mixing enhancement

Chiekh¹,

Béra²,

Sunyach³

2003

J. of Turbulence

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This experimental study examines the efficiency of wall pulsing control that is applied to a confined flow going through a two-dimensional diffuser continued by a duct. One-and dual-side pulsing generated by synthetic jet actuators are tested as control means. Particle image velocimetry is used to investigate instantaneous velocity fields and obtain quantitative information. One-side pulsing provokes vectoring of the primary flow in the same direction as the periodic excitation and increases its lateral expansion. Dual-side pulsing neutralizes vectoring but is more efficient for spreading. In both cases, the inner structure of the primary flow was found to be strongly modified, with the generation of highly periodic large-scale structures which kept the flow attached to the diffuser walls. The fluctuating velocity maps point out that the high-fluctuation zone greatly spreads out under control. The flow is considerably widened and the mixing is enhanced.

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“…The diffuser was designed such that injection could be introduced in the streamwise direction. Previous results obtained with cross-stream injection can be found in [4].…”

Section: Fluid Control In Diffusersmentioning

confidence: 99%

Synthetic jet control for flows in a diffuser: vectoring, spreading and mixing enhancement

Chiekh¹,

Béra²,

Sunyach³

2003

J. of Turbulence

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“…Le jet étudié est issu d'un canal de section rectangulaire, de largeur 12 cm et de hauteur h = 3 cm, terminé par un divergent plat et symétrique d'angle d'ouverture 2 × 45 • et de rapport de section de 4, qui débouche en espace libre. Le divergent a pour but d'amplifier l'effet du contrôle [9]. En entrée de divergent, on a un écoulement turbulent établi de conduite à vitesse moyenne de U 0 = 18 m/s, ce qui correspond à un nombre de Reynolds basé sur la hauteur h de 3,6 × 10 4 .…”

Section: Dispositif Expérimentalunclassified

Stimulation de l'élargissement d'un jet plan par contrôle fluidique alterné

Chiekh

Béra

Michard

et al. 2003

Comptes Rendus. Mécanique

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La présente étude expérimentale concerne le contrôle d'un jet plan par des injections fluidiques sinusoïdales à partir de deux actionneurs placés de part et d'autre du jet. La mesure des vitesses a été réalisée par vélocimétrie par images de particules (PIV). Nous avons pu montrer qu'un fonctionnement alterné des deux actionneurs, avec un timing bien choisi entre les périodes d'activité, augmentait l'efficacité des jets synthétiques pour la réalisation du mélange. Par rapport à une action permanente des deux côtés du jet, l'élargissement a pu être accru d'un facteur deux. Les cartes des énergies de fluctuation mettent en évidence une importante augmentation de la zone spatiale occupée par le mélange.

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“…However, for 𝑆𝑡 > 2, jet excitation led to a noise reduction if the action was sufficiently intensive. The self-sustaining sounds control was also considered by many others studies [31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47] Despite the study of some control techniques, the problem of noise reduction in impinging jets requires more effort to find better strategies. We therefore studied a passive control mechanism consisting of a 4 mm diameter rod installed between the jet exit and the impinging plate.…”

Section: Introductionmentioning

confidence: 99%

Effect of a Control Mechanism on the Interaction between a Rectangular Jet and a Slotted Plate: Experimental Study of the Aeroacoustic Field

Afyouni,

Alkheir,

Assoum

et al. 2023

Fluids

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The aeroacoustic field of a rectangular subsonic jet impinging on a slotted plate was investigated experimentally using microphones and stereoscopic particle image velocimetry (S-PIV). The study was carried out with a Reynolds number of 6700 and an impact distance of 4 cm. The current configuration represents a benchmark standpoint, featuring high levels of generated noise. A control mechanism consisting of a thin rod was introduced downstream from the jet exit to suppress the self-sustained tones. A total of 1085 positions of the rod between the jet exit and impinging plate were tested to identify positions of optimal noise reduction. Two zones were distinguished in terms of control efficacy: a zone where the sound pressure level (SPL) dropped by up to 19 dB and another zone where the SPL increased by up to 14 dB. The velocity fields show that the presence of the rod divides the jet into two lateral secondary jets on both sides of the main jet axis. The outer part of the secondary jets expanded radially with less interaction with the plate compared to the case without the control. This behavior affected the deformation of vortices against the slot. Proper orthogonal decomposition was applied to the velocity field for a better understanding of the turbulence dynamics with and without the control rod.

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Contrôle par jet pulsé de l'écoulement dans un divergent court à grand angle

Cited by 7 publications

References 5 publications

Synthetic jet control for flows in a diffuser: vectoring, spreading and mixing enhancement

Synthetic jet control for flows in a diffuser: vectoring, spreading and mixing enhancement

Stimulation de l'élargissement d'un jet plan par contrôle fluidique alterné

Effect of a Control Mechanism on the Interaction between a Rectangular Jet and a Slotted Plate: Experimental Study of the Aeroacoustic Field

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