Computational study of periodically unsteady interaction between a wall jet and an offset jet for various velocity ratios

Mondal, Tanmoy; Guha, Ayan; Das, Manab Kumar

doi:10.1016/j.compfluid.2015.09.015

Cited by 27 publications

(10 citation statements)

References 49 publications

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“…This paper addresses the decay of velocity of offset jets in the narrow and deep pool with various offset ratios, expansion ratios and jet exit shapes, through numerical simulations using a 3D computational fluid dynamics (CFD) model with the k-ε turbulence model coupled with VOF method, which was confirmed perform well in jet flow [10,[12][13][14][15][16][17].…”

Section: Introductionmentioning

confidence: 90%

Numerical Study of the Velocity Decay of Offset Jet in a Narrow and Deep Pool

Zhou

Zhang

et al. 2018

Water

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The present study examines the configuration of an offset jet issuing into a narrow and deep pool. The standard k-ε model with volume-of-fluid (VOF) method was used to simulate the offset jet for three exit offset ratios (OR = 1, 2 and 3), three expansion ratios (ER = 3, 4 and 4.8), and different jet exits (circular and rectangular). The results clearly show significant effects of the circumference of jet exits (Lexit) in the early region of flow development, and a fitted formula is presented to estimate the length of the potential core zone (LPC). Analysis of the flow field for OR = 1 showed that the decay of cross-sectional streamwise maximum mean velocity (Um) in the transition zone could be fitted by power law with the decay rate n decreased from 1.768 to 1.197 as the ER increased, while the decay of Um for OR = 2 or 3 was observed accurately estimated by linear fit. Analysis of the flow field of circular offset jet showed that Um for OR = 2 decayed fastest due to the fact that the main flow could be spread evenly in floor-normal direction. For circular jets, the offset ratio and expansion ratio do not affect the spread of streamwise velocity in the early region of flow development. It was also observed that the absence of sudden expansion of offset jet is analogous to that of a plane offset jet, and the flow pattern is different.

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Section: Introductionmentioning

confidence: 90%

Numerical Study of the Velocity Decay of Offset Jet in a Narrow and Deep Pool

Zhou

Zhang

et al. 2018

Water

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“…The standard − model was considered to be useful when applied to offset jet flow, Mondal et al [20], Kumar [21], and Mondal et al [22]. In addition, Assoudi (2015) believed that the standard − model is more appropriate for the prediction of the turbulent offset jet with small offset ratio (the offset ratio is 0.8 in this paper).…”

Section: Governing Equationsmentioning

confidence: 97%

Numerical Simulation of an Offset Jet in Bounded Pool with Deflection Wall

Wang

Zhang

2017

Mathematical Problems in Engineering

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The k-ε turbulent model and VOF methods were used to simulate the three-dimensional turbulence jet. Numerical simulations were carried out for three different kinds of jets in a bounded pool with the deflection wall with angles of 0°, 3°, 6°, and 9°. The numerical simulation agrees well with the experimental data. The studies show that the length of the potential core zone increases with the increase of the deflection angle. The velocity distribution is consistent with the Gaussian distribution and almost not affected by the deflection angle in potential core zone. The decay rates of flow velocity in the transition zone are 1.195, 1.281, 1.439, and 1.532 corresponding to the unilateral deflection angles, 0°, 3°, 6°, and 9°, respectively. The decay rates of velocity in the transition zone are 1.928 and 2.835 corresponding to the bilateral deflection angles 3° and 6°. It is also found that the spread of velocity is stronger in the vertical direction as the deflection angles become smaller. The spread rates of velocity with unilateral deflection wall are higher than those with bilateral deflection walls in the horizontal plane in the pool.

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“…They considered a non-dimensional nozzles spacing and Reynolds number, respectively, as equal to 1 and 10,000. The results derived from Mondal et al [15] investigation show that when considering the velocity ratio between the values r = 0.78 and r = 1.34, it is remarked the presence of a periodic large-scale Von Karman-like vortex shedding phenomenon along the convergence zone. For the velocity ratio r ≤ 0.77 and r ≥ 1.35, this phenomenon ceases to appear.…”

Section: Introductionmentioning

confidence: 95%

“…Two-dimensional turbulent combined wall and offset jet (WOJ) flow has been numerically investigated by Mondal et al [15] based on the unsteady RANS model. The elaborated numerical model is validated on the experimental setup of Wang and Tan [6] and Pelfrey and Liburdy [9], respectively, for WOJ flow and single offset jet flows.…”

Section: Introductionmentioning

confidence: 99%

Offset jet ejection angle effect in combined wall and offset jets flow: numerical investigation and engineering correlations

Hnaien

Marzouk

Kolsi

et al. 2019

J Braz. Soc. Mech. Sci. Eng.

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The present paper deals with a numerical study of turbulent flow which combines a wall jet and parallel offset jet. A parametric study was presented to pick out the offset ratio as well as the offset jet ejection angle influence on the merge point, combined point, upper vortex center and lower vortex center positions. Empirical correlations have been provided as a function of the offset ratio and the ejection angle. The main results obtained from the present investigation show that increasing the ejection angle displaces the merge point, the combined point and the vortices centers more upstream along the axial direction which accelerate the merging process launching. Furthermore, for higher value of the ejection angle, these mentioned points approach the horizontal wall along the lateral direction. Keywords Finite volume • Combined jets • Ejection angle • Merge point • Offset ratio List of symbols d Nozzle width (m) Greek symbols Kinematic viscosity (m²/s) Fluid density (kg/m 3) Offset jet ejection angle (OJEA) Subscripts 0 Exit value (at the nozzle exit) a Ambient value m Maximum value t Turbulent value Abbreviations WOJ Wall offset jet LWJ Lower wall Jet UOJ Upper offset jet SOJ Single offset Jet UVC Upper vortex center LVC Lower vortex center MP Merge point CP Combined point OJEA Offset jet ejection angle

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Computational study of periodically unsteady interaction between a wall jet and an offset jet for various velocity ratios

Cited by 27 publications

References 49 publications

Numerical Study of the Velocity Decay of Offset Jet in a Narrow and Deep Pool

Numerical Study of the Velocity Decay of Offset Jet in a Narrow and Deep Pool

Numerical Simulation of an Offset Jet in Bounded Pool with Deflection Wall

Offset jet ejection angle effect in combined wall and offset jets flow: numerical investigation and engineering correlations

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