PIs: Professor Xue-Feng YUAN, Dr Haiming Huang; Prof Carlo Massimo Casciola and Dr Alberto Giacomello at Sapienza University of Rome, Italy
It has been shown that nanoscale textures are capable of making superhydrophobicity robust by enhancing its lifetime and stabilising it over a broad range of pressures. However, for applications such as drag reduction it is advantageous to realise coatings with larger size, which are capable of interacting with the flow. A promising solution for these applications is that of hierarchical structures, which are also present in nature: the nanoscale features guarantee robustness, while the larger scale one are capable of modifying the flow. Simulating the effect of such multiscale surfaces underwater is currently very challenging. Only one scale can be afforded in standard computations, neglecting the interaction between the wetting state of the surface and the flow or the presence of surface features of different sizes. By utilizing molecular dynamics on extra-large scale parallel machines (“Tianhe-2”) and other supercomputers in Europe, this project aims at filling this gap by simulating a very large system with a hierarchical coating combining 1-nanometer robust textures and 10-nanometer ones, hence to shed light on the complex interaction between the fluid flow and the wetting state of the surface, with the ambition to move towards real-world applications in which hierarchical surfaces are employed. The long term goal of this study is finding design criteria for superhydrophobic coatings which are both robust and have optimal drag-reducing capabilities. From the fundamental side, the project also aims at developing multiscale methods in which molecular dynamics is coupled with continuum fluid mechanics.