Flow field topology of submerged jets with fractal generated turbulence

• DOI: 10.1063/1.4935185
• Publication Date: 2015-11-09T18:03:02Z
• Authors: Gioacchino Cafiero; Stefano Discetti; Tommaso Astarita
• Keywords: 0103 physical sciences; Condensed Matter Physics; 01 natural sciences; 532

Fractal grids (FGs) have been recently an object of numerous investigations due to the interesting capability generating turbulence at multiple scales, thus paving way tune mixing and scalar transport. The flow field topology a turbulent air jet equipped with square FG is investigated by means planar volumetric particle image velocimetry. comparison well-known features round without generators also presented. Reynolds number based on nozzle exit section diameter for all experiments set about 15 000. It demonstrated that presence grid enhances entrainment rate and, as consequence, transfer jet. Moreover, effect external shear layer wake shed bars, production region past significantly shortened respect documented behavior fractal in free-shear conditions. organization large coherent structures case analyzed discussed. Differently from generation toroidal vortices growth azimuthal disturbances within layer, introduces cross-wise disturbs which produce streamwise vortices; these structures, although characterized lower energy content, deeper penetration than ring vortices, enhancing process.