Simultaneous Measurements of Surface Spanwise Waves and Velocity in a Turbulent Boundary Layer

Abstract

AbstractAmong the different passive and active techniques for skin friction drag reduction for turbulent boundary layers, near wall forcing through moving walls is one of the most promising techniques at low Re$$_\tau$$ τ . Fewer studies have looked at the mechanism at high Re$$_\tau$$ τ , closer to flight conditions, largely because, in this regime, numerical simulations become harder and experiments more challenging. To that end, there is the need of a systematic study for different surface waves and flow conditions. This work introduces a new model using a kagome lattice and an experimental setup which combines simultaneous measurements of surface displacement and velocity in the boundary layer. Here the results from a shortened version of the model at Re$$_\tau \approx$$ τ ≈ 1000 are presented to demonstrate the capability of the experimental setup which is developed in view of further investigation at higher Reynolds number.