Transition to Turbulence through Intermittence in Inert and Reacting Jets

Леманов, В. В.; Lukashov, Vladimir V.; Sharov, K. A.

doi:10.1134/s0015462820060087

Cited by 7 publications

(9 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…An interesting study by Lemanov, Lukashov & Sharov (2020) demonstrated a new mechanism of transition to turbulence. A jet flows out of a pipe with Reynolds numbers Re = 1900-3500, at which the pipe flow was intermittent: mostly laminar with localized turbulent puffs.…”

Section: For Details)mentioning

confidence: 99%

Experimental validation of inviscid linear stability theory applied to an axisymmetric jet

et al. 2022

View full text Add to dashboard Cite

We study the development of perturbations in a submerged air jet with a round cross-section and a long laminar region (five jet diameters) at a Reynolds number of 5400 by both inviscid linear stability theory and experiments. The theoretical analysis shows that there are two modes of growing axisymmetric perturbations, which are generated by three generalized inflection points of the jet's velocity profile. To validate the results of linear stability theory, we conduct experiments with controlled axisymmetric perturbations to the jet. The characteristics of growing waves are obtained by visualization, thermoanemometer measurements and correlation analysis. Experimentally measured wavelengths, growth rates and spatial distributions of velocity fluctuations for both growing modes are in good agreement with theoretical calculations. Therefore, it is demonstrated that small perturbations to the laminar jet closely follow the predictions of inviscid linear stability theory.

show abstract

Section: For Details)mentioning

confidence: 99%

Experimental validation of inviscid linear stability theory applied to an axisymmetric jet

et al. 2022

View full text Add to dashboard Cite

show abstract

“…Despite the fact that the jet, as it is shown by comparison with the theory in figure 4a, corresponds to the Landau-Squire laminar solution along the entire length, pulsations in the mixing layers reach a level of 4.7% at x/D = 31. Downstream, according to our previous works, a transition to a turbulent flow occurs [10].…”

Section: Resultsmentioning

confidence: 62%

“…The laminar-turbulent transition in such flows occurs within the initial section (x/D < 4-6) [5][6]. The outflow from jet sources of different geometry (holes, pipes and channels, diffusers) has been studied much less [7][8][9][10]. At the same time, such configurations are encountered in practice.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Characteristics of the circular subsonic laminar jets flow with an initial Poiseuille profile

Леманов

Терехов

Sharov

et al. 2021

J. Phys.: Conf. Ser.

View full text Add to dashboard Cite

In this work, the experimental data are compared with the version of the “strong” jet (Re ≫ 1) of the exact Landau-Squire solution. The experiments were performed for a submerged air jet flowing out of a tube with a diameter of D = 3.2 mm and a length of more than 100D at a Reynolds number equal to Re = 436. The initial conditions in the jet are the Poiseuille velocity profile, the level of velocity pulsations is less than 1%. Measurements were carried out using a hot-wire anemometer. It is shown that satisfactory agreement with theory is achieved at distances from the tube starting from x/D = 5.6 and up to the zone of transition to turbulence (x/D > 35). Turbulence along the jet axis will increase from 1% to 2.5%, while in the mixing layers it increases to 4.7%.

show abstract

“…Unlike the pipe stream, the sets of eddies in a free jet flow into a free space acting on a mixing layer. Lemanov et al [5] demonstrated that disturbance of the mixing layer may have a delay in time after full flow laminarization at the axis of the jet. In thermally stratified flows scenarios of puff effect on the mixing layer apparently has to depend significantly on the density gradient in radial direction.…”

Section: Introductionmentioning

confidence: 99%

Effect of Local Turbulent Structures on the Hot Jet in Transitional Flow

Sakhnov

Lukashov

2021

J. Phys.: Conf. Ser.

View full text Add to dashboard Cite

Turbulent parts localized in flow direction may arise in a pipe with transitional regime of the stable laminar Poiseuille flow. A key condition for occurrence of such structures is a pipe with rather long length relative to its diameter. Our paper presents numerical modelling of the hot air jet flowing from the long pipe into the cold open volume at Re=2426. The modelling was performed in OpenFOAM software on the basis of the large eddy simulation (LES) method. The WALE (Wall-adapting local eddy-viscosity) model was used for closure of Navier-Stokes equations on subgrid scales. We demonstrated that local turbulent structures have a weak effect on the hot jet at flowing into the cold open volume.

show abstract

Transition to Turbulence through Intermittence in Inert and Reacting Jets

Cited by 7 publications

References 22 publications

Experimental validation of inviscid linear stability theory applied to an axisymmetric jet

Experimental validation of inviscid linear stability theory applied to an axisymmetric jet

Characteristics of the circular subsonic laminar jets flow with an initial Poiseuille profile

Effect of Local Turbulent Structures on the Hot Jet in Transitional Flow

Contact Info

Product

Resources

About