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

Experimental investigation of the turbulent flow field 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 flow field 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