Numerical simulation of isothermal flow in axisymmetric turbulent opposed jets

A numerical simulation has been carried out to study the steady and unsteady flow in axisymmetric turbulent opposed jets. The study is based on the solution of the complete Navier-Stokes equations and turbulence models using a finite volume technique. The tridiagonal matrix algorithm (TDMA) is used to solve the discretization equations. The pressure-velocity coupling is achieved using the SIMPLE method. Simulation is carried out for a range of Reynolds number 5000 <= Re <= 11 700, the ratio of the distance between the exits of two nozzles to the exit nozzle diameter 0.4 <= H/d <= 1.0 and the flow time. The results show that the radial velocity increases in downstream direction until maximum and then decreases. This change depends on the distance between the nozzle exits and the flow time. The axial velocity decays in the down stream direction on the axial direction. The turbulent kinetic energy and the normal stress in the axial direction increase and they become a maximum at the stagnation point, which occurs on the separation plane. The pressure at the stagnation point decays in downstream direction. This decay decreases by increasing the distance between the nozzles. The comparison between the numerical results and previous experimental measurements gives better agreement for v'(2)-f turbulence model than RNG model and k-epsilon standard model. (C) 2010 Elsevier Masson SAS. All rights reserved.