Abstract

In this talk, we summarise some of our earlier results on the visual appearance of turbulence boundary layers, and the dominant vortical structures therein. In particular, we address the question of the prevalence of hairpin-type vortices in the near-wall region, both close and further away from the transition point. While doing so, we also review some aspects of simulations of turbulent boundary layers in general.In a second part, we take a more modern view on turbulence structures, and analyse shear-stress (uv) structures in both duct and flows on wings. Eventually we analyse the effect of pressure gradients (clearly appearing on the suction side of wings) on the development of coherent structures, and see to what extent classical control strategies (suction and blowing) lead so similar effects. The content of this presentation is based on the PhD thesis of Marco Atzori, and earlier collaborations with Georg Eitel-Amor, Ramis Örlü, Dan Henningson and Fazle Hussain.