Investigation of unsteady processes, flow properties, and tonal acoustic radiation of a swirling jet

Zakharov, D. L.; Krasheninnikov, S. Yu.; Maslov, V. P.; Mironov, A. K.; Toktaliev, Pavel

doi:10.1134/s0015462814010086

Cited by 12 publications

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“…Thus, the return flow produces jet flow instability which leads to a flow pattern with periodic disturbances. In accordance with the experimental data [9,13,14], these disturbances manifest themselves as precession motion in the jet flowfield.…”

Section: Experimental Investigation Of the Propagation Of Disturbancesupporting

confidence: 87%

“…The synchronization was realized using the reference (filtered) microphone signal placed at the same point in both experiments. In The phase-average flowfields in the swirling jet for successively increasing values of ΔΦ from 0 to 360 ∘ are presented in [9]. They are analogous to the parameter distributions plotted in Fig.…”

Section: Experimental Investigation Of the Propagation Of Disturbancementioning

confidence: 86%

“…(As shown in [9], in a strongly swirling jet the pressure field rotates and, due to large rarefaction within it, produces intense disturbances in the induced ejected flow. The frequency of these disturbances coincides with the frequency of the sound waves emitted by the propagating jet).…”

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confidence: 98%

“…This means that the motion of large-scale turbulent-fluid regions in usual jets and the pressure field precession in swirling jets described in [9] produce similar disturbances in the ambient medium, so that it can be expected that the properties of the acoustic fields produced by them will also be similar.…”

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confidence: 99%

“…The investigations of strongly swirling jets made in [9] show that the unsteady motion of the low-pressure regions produces unsteady flow in the ambient medium. In this case, the low-pressure regions induce the ambient medium ejection.…”

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confidence: 99%

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Investigation of the generation of sound waves produced by turbulent jets

et al. 2015

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Free turbulent jets produce disturbances in the ambient medium which at a certain distance from the jet are perceived as sound waves. These disturbances are due to unsteady fluctuating motion of the medium in the jet flow (intermittance). The origin of the acoustic disturbances can be attributed to turbulence intermittance. Due to lowered pressure in the movable dynamic inhomogeneities of the turbulent fluid, they induce air ejection by the jet, which turns out to be fluctuating in nature, since the turbulent fluid flow is unsteady. The proposed mechanism of the generation of acoustic disturbances accompanying turbulent jet propagation is verified in numerical and experimental studies; in particular, the formation of acoustic fluctuations in the half-space over a surface which contains an embedded fluctuating finite-size sink is considered on the basis of the numerical solution of the unsteady Reynolds equations. From the results of the numerical experiment performed using large eddy simulation the fluctuating characteristics of the flow in a swirling jet and the direction of the disturbance energy flux in the ambient medium are determined. An experimental investigation of the disturbances produced by a strongly swirling jet is also carried out. Fig. 8. Profiles of the mean velocity components at a distance X = 40 mm from the nozzle exit; (1) IDDES and (2) experiment. FLUID DYNAMICS Vol. 50 No. 3 2015 FLUID DYNAMICS Vol. 50 No. 3 2015 386 KRASHENINNIKOV et al.According to the data obtained for the swirling jet the flux of the sound fluctuation energy is formed in the ejected flow, starting from the region boundary, on which ⟨p ′ v ′ ⟩ = 0. It increases with decrease in the phase difference between the velocity and pressure fluctuations, upon transformation of the fluctuating motion energy in the ejected flow to the acoustic energy. In the case of free turbulent jets the process is apparently analogous, since, according to [7,8], the ejection effects are similar in both cases.The study was carried out with the support of the Russian Foundation for Basic

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Section: Experimental Investigation Of the Propagation Of Disturbancesupporting

confidence: 87%

Section: Experimental Investigation Of the Propagation Of Disturbancementioning

confidence: 86%

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confidence: 98%

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confidence: 99%

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confidence: 99%

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