Flow structure and turbulence in near fields of circular and noncircular jets

Abstract

Experimental investigation of the turbulent §ow ¦eld of jets emanating from circular and curved-edged noncircular nozzles is conducted using hotwire anemometry. Distributions of the mean velocity vector are obtained by traversing a triple-sensor hot-wire probe at varying streamwise locations downstream of the jet exit plane in a low-speed free-jet facility. Measurements are obtained for a baseline circular nozzle (round jet) and for equilateral triangular and square nozzles. The data are used to compare the structure of the §ow ¦eld within these jets such as their mean velocity, turbulent kinetic energy, and entrainment levels. Axis rotation phenomenon is also investigated for noncircular nozzles, and it was not observed up to a streamwise location of 10d (d is the nozzle equivalent diameter, equals to 40 mm) for noncircular nozzles.

Effects of Noncircular Inlet on the Flow Structures in Turbulent Jets

“…From a literature survey, previous studies were conducted on the turbulent flow of a jet issuing from differrently shaped nozzles [1][2][3][4][5]. From their results, it was found that the near-field flow of the jet is strongly influenced by the three-dimensional structure dependent on the loss of axisymmetric nature.…”