Experimental and numerical study of an offset jet with different velocity and offset ratios

Assoudi, Ali; Habli, Sabra; Saïd, Nejla Mahjoub; Bournot, Hervé; Palec, Georges Le

doi:10.1080/19942060.2015.1071525

Cited by 11 publications

(9 citation statements)

References 40 publications

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“…Miozzi et al [16] experimentally studied the effect of lateral wall placing at different distances from the jet outlet. Assoudi et al [17] investigated the mean velocity and turbulence characteristics of the turbulent offset jet using a particle image velocimetry technique at three velocity ratios and for two offset ratios. Also, Assoudi et al [18] experimentally and numerically investigated the flow field of variable density turbulent offset jet.…”

Section: Figure 1 Schematic Design Of Offset Jet Flowmentioning

confidence: 99%

Investigation of k-ε Turbulent Models and Their Effects on Offset Jet Flow Simulation

Boroomand

Mohammadi

2019

Civ Eng J

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In the case in which relatively low thickness and high-velocity flow enter into the lower velocity fluid, the resulting interference field of these two flows is called the jet. This phenomenon is the dominant output of power plants and some of the dams. The jets can be divided into two categories of free jets and confined jets, caused by the distance from the discharge to limited boundaries points. The offset jet is a type of confined jet in which both free surface and wall boundaries are near the diffusion location. The jet flow due to the extreme curvature in the main flow path and the proximal portion of this flow with solid boundaries have characteristics that make it difficult to solve with simple turbulence models.In this research, the offset jet phenomenon and related issues have been investigated. For this purpose, the offset jet flow pattern and probable factors in the complexity of this model have been simulated using Fluent software which analyses fluid flow in a two dimensional and three dimensional finite volume method. The simulation of offset jet flow pattern has been performed with a focus on investigating different models of turbulence k-ε, also boundary conditions, various wall functions and other effective coefficients in the numerical model and the model results compared with test case data findings and validating results, the necessary approaches in numerical simulation of this phenomenon for using in the next stages had been taken.

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Section: Figure 1 Schematic Design Of Offset Jet Flowmentioning

confidence: 99%

Investigation of k-ε Turbulent Models and Their Effects on Offset Jet Flow Simulation

Boroomand

Mohammadi

2019

Civ Eng J

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“…Regarding the inlet pressure influence on the characteristics of the parallel jet, Fujisawa [ 20 ] studied the interaction of two parallel plane jets under two different inlet velocities, and found that the interaction of the two parallel jets weakened with the decrease in the jet velocity ratio; Khazaei [ 21 ] found that the influence of the pressure of the dual parallel jet on the extraction effect is the most significant among many factors; Tian [ 22 ] studied the influence of pressure and nozzle target distance on jet impact pressure, and the results showed that both of them can effectively improve jet efficiency; Assoudi [ 23 ] found that the velocity ratio has a significant influence on the mean velocity and turbulence characteristics of the turbulent offset jet; Krishna Chandran [ 24 ] simulated the non-isothermal jet mixing phenomena and obtained result that suggested that the jets with a unity velocity ratio showed maximum temperature fluctuations; Wang [ 25 ] investigated the flow structure nearby a rectangular cooling hole on a flat plate and proved that the asymmetric vortex system with a different velocity ratios is stable; and Kwon [ 26 ] measured the heat transfer performance of the coolers for three electronic device configurations with varied jet velocity.…”

Section: Introductionmentioning

confidence: 99%

Influence of Non-Structural Parameters on Dual Parallel Jet Characteristics of Porous Nozzles

Zhang

Yang

et al. 2020

Micromachines

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As an important actuator of the dual parallel jet, the porous nozzle has some non-structural parameters (such as inlet pressure, nozzle spacing ratio, etc.) which have a significant influence on energy transport, chemical combustion and pollutant generation. The research on the microfluidic state of the porous nozzle dual parallel jet, however, remains insufficient because of its microjet pattern and complex intersection process. In this paper, the authors used numerical simulation and an experimental method to clarify the influence of porous nozzles’ non-structural parameters on dual parallel jet characteristics. The results show that the inlet pressure only changes the pressure peak value on the parallel jet axis; the starting point (SP) and peak point (PP) on the parallel jet axis, which are located at Xsp = 22 mm and Xpp = 75 mm, respectively, are not changed; and with the increase in the nozzle spacing ratio, the merging points (MPs) on the parallel jet axis are Xmp = 25 mm, 32 mm and 59 mm, respectively. The merging point and the combined point move to a farther distance and the inner deflection angle of the jet is weakened.

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“…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). So the standard − turbulence model presented by Launder and Spalding (1972) was used.…”

Section: Governing Equationsmentioning

confidence: 99%

“…Agelin-Chaab and Tachie [7] reported that, in the early region of the flow development, the Reynolds number and the offset ratio have significant effects on the decay of the maximum mean velocity, but the decay and spread rates were found to be nearly independent of the offset ratio at lager downstream distances. Assoudi et al [8] had investigated the mean velocity and turbulence characteristics of the turbulent offset jet using PIV technique at 3 velocity ratios and 2 offset ratios; their results indicated that increasing the offset ratio gives a better distribution of the jet within the flow field, giving rise to a better dynamic mixture. Nyantekyi-Kwakye et al [9] studied experimentally the jet with different height ratios (0, 2 and 4); their work revealed that the large scale structures within the inner layer increase with wall normal distance from the pool bottom.…”

Section: Introductionmentioning

confidence: 99%

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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Experimental and numerical study of an offset jet with different velocity and offset ratios

Cited by 11 publications

References 40 publications

Investigation of k-ε Turbulent Models and Their Effects on Offset Jet Flow Simulation

Investigation of k-ε Turbulent Models and Their Effects on Offset Jet Flow Simulation

Influence of Non-Structural Parameters on Dual Parallel Jet Characteristics of Porous Nozzles

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

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