Scienfic talk at MPE: Controlling flows and heat transfer using complex surfaces

Abstract:

Over the past decades, superhydrophobic surfaces (SHS) have been studied extensively for turbulent drag reduction. While early controlled experiments and idealised simulations reported high drag reduction rates (which sparked a massive interest in SHS), the more recent efforts devoted to getting SHS to perform in more realistic conditions have been futile. However, our understanding has progressed as it has become clear that the air plastron,  responsible for drag reduction, is very fragile to many disturbance types. Liquid-infused surfaces (LIS), where a liquid is used as a lubricant instead of air, resolve the main failure modes of SHS while achieving a good drag reduction performance. Moreover, the degrees of freedom provided by the lubricant (viscosity, conductivity, etc) enable simultaneous control of skin friction and heat transfer. However, similar to SHS, liquid-infused surfaces have their own failure modes in turbulent flows related to the interfacial waves, drainage and Marangoni stresses. In this talk, I will summarise  current challenges and opportunities of using lubricated surfaces to control turbulent flows. Can we tame the many instabilities of these surfaces? Can we explore new ways of using these surfaces as sensors and actuators?