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

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

doi:10.1007/s00231-015-1750-9

Cited by 9 publications

(6 citation statements)

References 16 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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“…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. They claimed that a good level of agreement was achieved, between the experiments and the calculations.…”

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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“…The three-dimensional study on offset jet has also been done by some of the researchers. Assoudi et al 29,30 have used Particle Image Velocimetry (PIV) technique for the experimental study. They also used Reynolds stress turbulent model for the numerical work with finite volume method.…”

Section: Introductionmentioning

confidence: 99%

Effect of wavy wall surface on flow structure and thermal characteristics of a turbulent dual jet comprising of a wall jet and an offset jet

Singh

Kumar

Satapathy

2020

Proceedings of the Institution of Mechanical Engineers, Part A:

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The fluid flow and thermal characteristics of the dual jet are explored numerically. The dual jet is considered with a wavy wall surface having various amplitudes varying between 0.1 and 0.7 with a fixed number of cycles equal to 10. The offset ratio is also varied from 3 to 15 with an interval of 2. The Reynolds number and Prandtl number are set to 15,000 and 0.71, respectively. The Semi Implicit Method for Pressure Linked Equation algorithm is utilised to link the pressure to the velocity. To solve the set of linear algebraic equations Strongly Implicit procedure solver is used. The heat transfer characteristics of the wavy wall surface were studied for two cases: (1) isothermal bottom wall and (2) adiabatic bottom wall. It is found that the wavy wall affects the flow field and heat transfer characteristics drastically. The minimum pressure inside the domain is not found to occur at the vortex centre for all the offset ratios, which is the case of a dual jet with a plane wall. Results also reveal that as the amplitude of the wavy surface increases both local Nusselt number and local heat flux increase near the exit of the nozzle for each offset ratio. Further, it is also noticed that the average Nusselt number increases up to amplitude A = 0.5. Thereafter, it decreases with further increase in the amplitude of the wavy surface. It is found that the wavy surface increases the average Nusselt number by a maximum of 17.6% as compared to the plane wall case.

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

Cited by 9 publications

References 16 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

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

Effect of wavy wall surface on flow structure and thermal characteristics of a turbulent dual jet comprising of a wall jet and an offset jet

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