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Computational Thermal Sciences

ISSN Print: 1940-2503
ISSN Online: 1940-2554

Computational Thermal Sciences

DOI: 10.1615/ComputThermalScien.2012003883
pages 1-22


Mohsen Akbarzadeh
Department of Mechanical and Manufacturing Engineering, University of Manitoba, Winnipeg, Manitoba, R3T 5V6, Canada
Madjid Birouk
Department of Mechanical and Manufacturing Engineering, University of Manitoba, Winnipeg, MB, R3T 5V6 Canada
Brahim Sarh
ICARE-CNRS, 1С Avenue de la Recherche Scientifique, Orléans 4571, France


The aim of this paper is to demonstrate that the simple Reynolds-averaged Navier-Stokes (RANS) two-equation standard kε turbulence model is capable of predicting the main characteristics of turbulent free jets issuing from three-dimensional complex rectangular nozzle geometry. This paper also investigates the main characteristics of turbulent rectangular free shear jets by varying the nozzle aspect ratio. The computations were performed by using RANS equations and the turbulence terms were handled by testing the standard two-equation kε or kω turbulence models. The solution of the governing equations was obtained by using the finite volume method (FVM), where the SIMPLEC algorithm was adopted with a staggered grid to prevent decoupling velocity and pressure fields. The inflow boundary conditions including the inflow velocity profile and the turbulence intensity level were adopted from published experimental data. The main results demonstrate that the standard kε model, when applied with appropriate inflow boundary conditions, provides successful predictions of the main features of turbulent free jets issuing from rectangular nozzles, including the decay rate in the near- and far-field region, the spreading rate except in the very near field, vena contracta, and axis switching. The numerical results show also that increasing the nozzle aspect ratio leads to an increase in fluid entrainment closer to the nozzle exit in the near field, which is in complete agreement with experimental observations.