Downstream Evolution of Perturbations in a Zero Pressure Gradient Turbulent Boundary Layer

etc15 Tracking Number 161

This abstract examines the evolution of perturbations generated by various trips in a turbulent boundary layer. Measurements taken using hot wire anemometry show that the evolution towards the natural state is strongly dependent on the formation mechanisms of the boundary layer, this being different for different wall normal distribution of the trips' blockage. It is observed that standard boundary layer properties are recovered, after an adaptation region, with $175\%$ higher momentum thickness than the natural case. Two-point measurements with time resolved velocity in the inner region are studied to explore the different formation mechanisms.