Numerical Simulation of the Vortical Structures in a Lobed Jet Mixing Flow (original) (raw)

Abstract

Numerical simulations of an incompressible jet mixing flow exhausted from a circular lobed mixer/nozzle were presented and validated against whole-field quantitative Dual-Plane Stereoscopic PIV (DP-SPIV) measurement results of the same flow. The numerical simulations were conducted using a Reynolds Averaged Navier-Stokes approach with a modest number of unstructured tetrahedral cells and four widely used turbulence models to predict the vortex structures in a lobed jet mixing flow. The predictability of the turbulence models to the lobed jet mixing flow were assessed and quantified based on quantitative comparisons of the numerical predictions with the DP-SPIV measurement results. It is found that the numerical simulations agree with the experimental measurements reasonably well in terms of streamwise vorticity and azimuthal (spanwise) vorticity. Although all the four turbulent models investigated over predict the magnitude of the turbulent kinetic energy significantly (about 50% to 130% over predicted), the numerical simulations are found to agree with the experimental results in predicting the locations of the regions with high turbulent kinetic energy, and the trends associated turbulent kinetic energy production and decay with downstream distance. It is found that the k-ε Realizable turbulence model provides the most accurate prediction of the lobed jet mixing flow among the turbulence models compared. Nomenclature

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