Flow characteristics within the recirculation region of three-dimensional turbulent offset jet

Nyantekyi-Kwakye, Baafour; Clark, Shawn P.; Tachie, Mark F.; Malenchak, Jarrod; Muluye, Getnet Y.

doi:10.1080/00221686.2014.950612

Cited by 34 publications

(25 citation statements)

References 25 publications

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“…The initial conditions and development of the 3D wall and offset jets (i.e. distribution of U m , y m , y 0.5 and z 0.5 ) have been thoroughly discussed and presented by Nyantekyi-Kwakye et al (2015) and as such will not be reported here. Figure 3 shows contours of U* = U/U o for the offset jets, with x* and y* denoting x/b o and y/b o , respectively.…”

Section: Resultsmentioning

confidence: 98%

“…The turbulent length scales within the self-similarity region at y r /y m = 0.5 were estimated from streamwise and wallnormal extents of the 0.6 contour levels. This approach has been described in detail by Nyantekyi-Kwakye et al (2015). Values of Lx uu , (streamwise extent of R uu ), Ly uu , (wall-normal extent of R uu ), Lx vv (streamwise extent of R vv ) and Ly vv (wall-normal extent of R vv ) normalized by b o are presented in Table 1.…”

Section: Two-point Auto Correlationmentioning

confidence: 99%

“…To date, the most comprehensive studies on 3D offset jets are those reported by Davis & Winarto (1980), Agelinchaab & Tachie (2011b) and Nyantekyi-Kwakye, Clark, Tachie, Malenchak, & Muluye (2015). The investigation by Davis & Winarto (1980) utilized hot-wire anemometry to characterize the mean velocities and Reynolds stresses.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Experimental study of the flow structures of 3D turbulent offset jets

Nyantekyi-Kwakye

Tachie

Clark

et al. 2015

Journal of Hydraulic Research

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Three-dimensional turbulent offset jets were investigated using a particle image velocimetry technique. Detailed measurements were performed for offset height ratios of 0, 2 and 4. The presence of backflow influenced the distribution of the mean velocity and Reynolds stresses. A two-point correlation analysis was used to investigate the spatial distribution of large-scale structures within the inner shear layer of the flow domain. The results revealed that large-scale structures dominate the inner layer of the self-similarity region. Proper orthogonal decomposition was performed on the fluctuating velocity field within the symmetry and lateral planes using the snapshot approach. Results from the reconstructed field provided insight into the contributions of the most energetic structures to the turbulence statistics. The energetic structures contributed more to the Reynolds shear stress and streamwise turbulence intensity, while contributing less to the wall-normal turbulence intensity.

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Section: Resultsmentioning

confidence: 98%

Section: Two-point Auto Correlationmentioning

confidence: 99%

See 1 more Smart Citation

Experimental study of the flow structures of 3D turbulent offset jets

Nyantekyi-Kwakye

Tachie

Clark

et al. 2015

Journal of Hydraulic Research

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“…The 3D offset jet flow is significantly different in configuration to previous experimental studies reviewed since there is a primary recirculation region due to the elevation of the jet from the bottom of the channel. Investigations by Nyantekyi-Kwakye et al [8] and Agelinchaab Downloaded by [University of York] at 07:15 10 June 2016 and Tachie [9] revealed that large scale structures responsible for mixing and entrainment of the jet increased in size with increasing offset height ratio of the 3D jet. These structures were observed to be more dynamically dominant in the outer shear layer than in the inner shear layer of the flow.…”

Section: Introductionmentioning

confidence: 96%

“…The objective of this study is therefore to investigate the effect of rib location on the flow structures of a 3D offset jet. The present experiment was performed at Reynolds number and flow condition similar to previous studies by Nyantekyi-Kwakye and co-workers [8,10]. Detailed velocity measurements were performed in the symmetry plane (where the interaction of the inner and outer shear layers can be modified in the presence of a surface mounted rib) using planar particle image velocimetry.…”

Section: Introductionmentioning

confidence: 97%

Flow characteristics of an offset jet over a surface mounted square rib

Nyantekyi-Kwakye

Tachie

Clark

2016

Journal of Turbulence

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A three-dimensional offset jet flow over a surface mounted square rib was investigated using particle image velocimetry at Reynolds number of 7600. The square rib was mounted at three different locations downstream of the nozzle exit. Contour and profile plots in the symmetry plane were used to investigate the effect of the rib on the mean flow distribution and turbulence statistics. Changing the rib location enhanced the mixing and entrainment characteristics of the jet thereby leading to larger wall-normal spread rates. The quadrant analysis revealed a significant contribution of all events towards the Reynolds shear stress. The joint probability density function analysis showed that the structures within the outer shear layer of the jet differed from those of boundary layers. Results from the two-point correlation analysis indicated that the introduction of a surface mounted rib modified the flow structures within the developing region. However, there was no significant structural difference between the flow with mounted rib and the no rib case within the self-similar region. The proper orthogonal decomposition was used to examine how changes in rib location modified the dynamics of the energetic modes towards the turbulent kinetic energy and Reynolds shear stress within the developing and self-similar regions.

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Three-dimensional study of turbulent flow characteristics of an offset plane jet with variable density

et al. 2015

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International audienceAn experimental and numerical investigation of the flow field of variable density turbulent offset jet is presented. The velocity measurements are performed using a Velocimetry Laser Doppler technique for an offset height h. Three cases of variable-density turbulent plane jets discharging from a rectangular nozzle into a quiescent medium are studied. The variation density jets considered were revealed at different Reynolds numbers. In the second step of this work, a numerical three-dimensional model of the problem is simulated through the resolution of the Navier-Stokes equations by means of the finite volume method and the Reynolds stress model second-order turbulent closure model. A non-uniform mesh system tightened close to the emitting nozzle and both the vertical and horizontal walls is also adopted. A good level of agreement was achieved, between the experiments and the calculations. Once the model validated, our model allowed the evaluation of the influence of the variation density on the characterizing features of the resulting flow filed. It is found that the centerline velocity and concentration of the heavier jet decays much faster than in the two other jets, and a similar behavior for the vertical profiles in the three variable-density jets is well reproduced in the simulation

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Flow characteristics within the recirculation region of three-dimensional turbulent offset jet

Cited by 34 publications

References 25 publications

Experimental study of the flow structures of 3D turbulent offset jets

Experimental study of the flow structures of 3D turbulent offset jets

Flow characteristics of an offset jet over a surface mounted square rib

Three-dimensional study of turbulent flow characteristics of an offset plane jet with variable density

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