Author(s): Seok Jae Kwon; Il Won Seo
Linked Author(s): Il Won Seo
Keywords: Circular pure jet; PIV; Reynolds number; Laminar or turbulent flow
Abstract: The hydraulic experiments for the behavior of a circular pure water jet discharged from a contraction nozzle were performed in the range of the initial Reynolds numbers from 177 to 5, 142 using PIV system. The length of ZFE was observed to decrease with the increase of the Reynolds numbers. The measured centerline velocity decayed more rapidly and consequently approached to the theoretical equation earlier near the nozzle as the Reynolds number increased. The jet half width grew with the longitudinal distance for the turbulent flows whereas it seldom grew for the laminar or transitional flows. The spreading rates for the turbulent flows gradually decreased with the increase of the Reynolds number. The normalized turbulent intensity along the jet centerline increased more rapidly with the longitudinal distance as the Reynolds number increased and tended to approach to the constant values proposed by previous investigators. The Reynolds shear stress levels were also found to increase as the Reynolds number increased for the turbulent jets.