The Structure of Turbulence Over Smooth and Rough Walls

375 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2001.Several spanwise lengthscales are shown to vary linearly with distance from the wall, revealing self-similar growth of spanwise structure in an average sense. However, inspection of the data suggests individual structures do not grow strictly self-similarly in time. It is proposed that additional scale growth occurs by the merging of vortex packets on an eddy-by-eddy basis via a vortex leg-annihilation mechanism similar to that suggested by Perry and Chong (1982). The proposed mechanism provides a link between vortex-pairing concepts and the observed coalescence of streaky low-speed regions in the inner layer.U of I OnlyRestricted to the U of I community idenfinitely during batch ingest of legacy ETD