Introducing perturbations into turbulent wall-bounded flow with arrays of long TiO₂ nanowires

A currently unexplored mechanical application of nanowires is near-wall active flow manipulation, with potential uses mixing and filtering chemicals, enhancing convective heat transfer, and reducing drag. Here, we present experimental evidence that it is possible to introduce persistent perturbations into turbulent flow with active nanowires. A TiO2 nanowire array was fabricated and installed in the bounding wall of a turbulent channel flow, and the array was oscillated by external actuation. Measurements indicated that the array increased turbulent kinetic energy throughout the entire wall layer. These findings suggest that dynamically actuated nanowires can potentially be used to implement near-wall flow control.