Effect of initial conditions on a circular jet

Abstract

 Two circular jets are considered. One issues from a contraction with a laminar top-hat velocity profile. The other exits from a pipe with a fully developed turbulent mean velocity profile. In spite of the significantly different initial conditions, spectra of axial and radial velocity fluctuations in the far field (x≳30d, where d is the jet diameter) collapse over scales ranging from the Kolmogorov length scale to a length scale characterizing the organized motion. This agreement is consistent with the observation that, at the measurement station, the large-scale anisotropy is unchanged between the two flows.