Rough-wall turbulent boundary layers under external disturbances

Rough-wall boundary layers are ubiquitous in engineering and environmental applications. Most previous studies have examined turbulent boundary layers over rough-walls in a canonical setting with either a zero pressure gradient or a laminar flow in the freestream. However, in practice, most flows either have a favourable of adverse pressure gradient (such as airfoils, ship hulls etc) or have freestream disturbances. The effect of these external influences on the boundary layer flow remains unexplored. In this project, we will use high fidelity diagnostics (PIV, drag balance etc) in order to understand the flow over rough-walls that are under pressure gradients and freestream turbulence. Brand-new state-of-the-art facilities in the Boldrewood campus (new wind tunnel and water flume) will be used for these measurements.