Spectral Linear Stochastic Estimation of the Turbulent Velocity in a Square Three-Dimensional Wall Jet

The instantaneous turbulent velocity field in a three-dimensional wall jet was estimated from the fluctuating wall pressure using a spectral Linear Stochastic Estimation (LSE) technique. The jet issued from a long square channel with Reynolds number of 90,000. Two downstream positions in the intermediate field were examined, x/h = 10 and x/h = 20, owing to the rapid change in wall jet development over this region. The results indicate that the passage of the large-scale structures causes large, coherent lateral sweeps of fluid across the entire span of the wall jet. The sweeps appear to be caused by the passage of half horseshoe-like structures. As the structures evolve downstream they develop a longer outer leg, and become more offset, traits that both contribute to the large lateral growth of this flow.