Experimental investigations of a swirling jet in both stationary and rotating surroundings

Liang, Hanzhuang; Maxworthy, T.

doi:10.1007/s00348-008-0478-4

Cited by 20 publications

(14 citation statements)

References 29 publications

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“…As [27] has shown, the shear between the rotating jet and the ambient fluid seems to play a secondary role in this case. Thus, it can be expected that the flow structure of swirling jets with vortex breakdown and precession of the vortex core manifests some common features, even for rather different nozzle geometries.…”

Section: Introductionmentioning

confidence: 88%

Flow Structure of Swirling Turbulent Propane Flames

Алексеенко

Дулин

Kozorezov

et al. 2011

Flow Turbulence Combust

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Flow structure of premixed propane-air swirling jet flames at various combustion regimes was studied experimentally by stereo PIV, CH* chemiluminescence imaging, and pressure probe. For the non-swirling conditions, a nonlinear feedback mechanism of the flame front interaction with ring-like vortices, developing in the jet shear layer, was found to play important role in the stabilisation of the premixed lifted flame. For the studied swirl rates (S = 0.41, 0.7, and 1.0) the determined domain of stable combustion can be divided into three main groups of flame types: attached flames, quasi-tubular flames, and lifted flames. These regimes were studied in details for the case of S = 1.0, and the difference in the flow structure of the vortex breakdown is described. For the quasi-tubular flames an increase of flow precessing above the recirculation zone was observed when increased the stoichiometric coefficient from 0.7 to 1.4. This precessing motion was supposed to be responsible for the observed increase of acoustic noise generation and could drive the transition from the quasi-tubular to the lifted flame regime.

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Section: Introductionmentioning

confidence: 88%

Flow Structure of Swirling Turbulent Propane Flames

Алексеенко

Дулин

Kozorezov

et al. 2011

Flow Turbulence Combust

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“…As already mentioned, the strong shear in the tangential velocity that has been detected downstream from the splitter lip separating outer and inner swirler flows could be receptive to develop KH instability waves. The presence of shear layer instabilities in suddenly expanded swirling jets has been reported when studying KH instabilities in swirling flows that evolve into a fluid at rest at moderately high Reynolds numbers (Re = O (10 3 )) [14]. However in that investigation the vortical structures were generated in the shear layer formed between the swirling jet and an almost stagnant, surrounding flow, as no shear layer occurred within the swirling jet nozzle.…”

Section: Inter-modal Couplingmentioning

confidence: 94%

“…In certain cases, the vorticity field convected along the VBD can be redistributed and organized into additional large scale patterns [1,14,19,20]. In addition, large scale flow modes have also been reported having their origin in the shear instability that forms between the swirling jet and the discharge enclosure flow [14].…”

Section: Introductionmentioning

confidence: 97%

“…For moderate to large enclosure ratios and sufficiently high Reynolds numbers (Re > 10 3 ), a well know instability mechanism appears as the VBD region undergoes a large scale, bulk motion known as precessing vortex core (PVC) [3,4,8,12,16,17,[20][21][22][23]. In certain cases, the vorticity field convected along the VBD can be redistributed and organized into additional large scale patterns [1,14,19,20]. In addition, large scale flow modes have also been reported having their origin in the shear instability that forms between the swirling jet and the discharge enclosure flow [14].…”

Section: Introductionmentioning

confidence: 99%

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On the coherent modes of high Reynolds number, strongly swirling jets discharging in compact enclosures. Part B: Coherent flow structure

González-Martínez

Lázaro

2015

Aerospace Science and Technology

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“…Liang and Maxworthy [8] and Liang and Maxworthy [12] used a long rotating pipe attached to a large water tank to generate swirling jets. The authors conducted experiments at Reynolds numbers up to Re D = 2000 (based on the bulk velocity).…”

Section: Introductionmentioning

confidence: 99%

Impact of rotating and fixed nozzles on vortex breakdown in compressible swirling jet flows

Luginsland

Gallaire

Kleiser

2016

European Journal of Mechanics - B/Fluids

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a b s t r a c tVortex breakdown of swirling, round jet flows is investigated in the compressible, subsonic regime by means of Direct Numerical Simulation (DNS). This is achieved by solving the compressible Navier-Stokes equations on a cylindrical grid using high-order spatial and temporal discretization schemes. TheReynolds number is Re = ρ The integral swirl number at the inflow is S int = 0.85. The parameters are chosen properly so as to make comparisons with existing experiments at lower Mach numbers possible while still enabling a study of compressible and baroclinic effects. Different from previous numerical investigations, a nozzle immersed in the fluid is included in the computational domain and is modelled as an isothermal no-slip wall, either rotating with the mean azimuthal flow direction or kept at rest. The present investigation aims to clarify the role played by the nozzle wall motion for the vortex breakdown of the swirling jet. We study the nozzle flow as well as the swirling jet flow simultaneously, a novelty for numerical investigations of vortex breakdown in swirling jets. Depending on the nozzle wall motion, the flow differs significantly upstream of the vortex breakdown: for the rotating nozzle, the flow inside the nozzle is purely laminar and the azimuthal boundary layer at the outer nozzle wall gives rise to the axisymmetric mode n = 0 and a single-helix type instability with azimuthal wave number n = 1. With the nozzle at rest, a transitional flow is observed within the nozzle where a helical instability with azimuthal wave number n = 12 dominates, growing in the boundary layer at the nozzle wall. For both nozzle setups, the helical instabilities observed for the nozzle flow interact with the developing vortex breakdown and the conical shear-layer downstream of the nozzle. For the nozzle at rest, this interaction results in a vortex breakdown configuration which is shifted in the upstream direction and which has a smaller radial and streamwise extent compared to the rotating nozzle case and the recirculation intensity is higher. The dominant frequency is highly influenced by the flow upstream of the vortex breakdown and is substantially higher for the nozzle at rest. Although the nozzle flow field differs for the two configurations and therefore alters the vortex breakdown downstream, a single-helix type instability n = 1 governing the vortex breakdown is found for both cases. This provides strong evidence for the robustness of the instability mechanisms leading to vortex breakdown.

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Experimental investigations of a swirling jet in both stationary and rotating surroundings

Cited by 20 publications

References 29 publications

Flow Structure of Swirling Turbulent Propane Flames

Flow Structure of Swirling Turbulent Propane Flames

On the coherent modes of high Reynolds number, strongly swirling jets discharging in compact enclosures. Part B: Coherent flow structure

Impact of rotating and fixed nozzles on vortex breakdown in compressible swirling jet flows

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