Investigation of Submerged Jets with an Extended Initial Laminar Region

Zaiko, Yu. S.; Решмин, А. И.; Teplovodskii, S. Kh.; Chicherina, A. D.

doi:10.1134/s0015462818010184

Cited by 9 publications

(4 citation statements)

References 15 publications

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“…As shown in [8], in this case the length of transition region reduces to 1-2 jet diameters. [4][5][6][7][8]. The characteristic feature of the jet under consideration is the presence of three inflection points in the inlet velocity profile.…”

Section: Nonlinear Interaction Of Perturbations and Turbulence Transi...mentioning

confidence: 99%

“…At large , turbulence transition in circular jets occurs, as a rule, in the immediate neighborhood of the nozzle exit section, within the distance of 1D (D is the nozzle diameter). Several years ago, a compact device for generation of circular air jets which ensures maintenance of laminar flow at (U b is the mean velocity in the inlet stream, ) at distances to ~6D at D = 0.12 m was designed and fabricated in the Institute of Mechanics of Moscow State University [4,5]. In this case, the dimension of the device is equal to approximately only .…”

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confidence: 99%

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Development of Disturbances in a Circular Submerged Jet with Two Instability Modes

Abdul’manov

Nikitin

2022

Fluid Dyn

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The stability and nonlinear interaction between the disturbances in a round jet are investigated numerically at Re = 2850. The conditions of the laboratory experiment performed earlier in the Institute of Mechanics of Moscow State University are reproduced. The characteristic feature of the jet considered is the presence of three points of inflection in the inflow velocity profile. This fact determines essentially the properties of flow. Linear stability is investigated using two approaches: quasi-parallel and spatial. Good quantitative agreement between the results of two approaches and adequate agreement with the results of inviscid theory are obtained. Numerical calculations are carried out with the aim to explain and interpret the results of the laboratory experiment in which change in the length of the laminar-turbulent transition zone in the jet under the action of time-periodic axisymmetric perturbations is revealed. It is shown that axisymmetric disturbances of even considerable initial amplitude do not lead to laminar-turbulent transition. The transition observed experimentally is attributable to the presence of non-controlled three-dimensional disturbances that are strengthened against the background of fairly intense artificial disturbances. The investigations carried out in the present study confirm this hypothesis. Thus, the three-dimensional disturbances serve as an initiator of transition, while the axisymmetric disturbances of a fairly high amplitude only accelerate their growth. It is shown that more intense three-dimensional disturbances are able to ensure still more rapid transition even in the absence of axisymmetric component.

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Section: Nonlinear Interaction Of Perturbations and Turbulence Transi...mentioning

confidence: 99%

mentioning

confidence: 99%

Development of Disturbances in a Circular Submerged Jet with Two Instability Modes

Abdul’manov

Nikitin

2022

Fluid Dyn

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“…In [11,12] the jet with a long laminar region and the facility forming it are described thoroughly. Hereinafter, the theoretical analysis and experiments are conducted for the flow with Re=5030, based on the diameter D and average velocity (the axis speed Uc=1.5 m/s).…”

Section: The Jet With a Long Laminar Regionmentioning

confidence: 99%

“…At the Institute of Mechanics of Lomonosov Moscow State University the facility has been created that generates a submerged jet of 0.12 m in diameter (D) and with a long laminar region ~5D at the Reynolds numbers (Re) in the range 5000 -10000 [11,12]. Such jet provides the possibility to conduct detailed experimental observations of perturbations growth and to compare them with predictions of the linear stability theory applied to velocity profiles at different distances from the orifice.…”

Section: Introductionmentioning

confidence: 99%

Comparison of Experimental and Theoretical Characteristics of Linear Waves in the Submerged Air Jet

Gareev¹,

Chicherina²,

Решмин³

et al. 2021

Proceedings of the 8th International Conference on Fluid Flow, Heat and Mass Transfer (FFHMT'21)

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A submerged air jet of round cross section, 0.12 m in diameter and with a long laminar region (up to 5 jet diameters) was obtained experimentally at the Reynolds number 5030. Using the linear stability analysis, two branches of growing perturbations were found, which are generated by three inflection points on the experimental jet profiles. Ranges of growing perturbation frequencies were obtained, as well as their growth rates, wavelengths and radial distributions of amplitudes. Experiments, in which controlled perturbations were introduced into the jet with a long laminar region, were conducted. Characteristics of waves, which are growing in experiments, are close to the predictions of the linear stability theory. Consequently, the linear stability theory applied to the submerged jet is validated experimentally.

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