"Flows of complex fluids, such as many biological fluids and most synthetic fluids, are common in our daily life and are very important from an industrial perspective. Because of their inherent nonlinearity, the flow of complex viscoelastic fluids often leads to counterintuitive and complex behaviour and, above critical conditions, can prompt flow instabilities even under low Reynolds number conditions which are entirely absent in the corresponding Newtonian fluid flows.The primary goal of this project is to substantially expand the frontiers of our current knowledge regarding the mechanisms that lead to the development of such purely-elastic flow instabilities, and ultimately to understand the transition to so-called “elastic turbulence”, a turbulent-like phenomenon which can arise even under inertialess flow conditions. This is an extremely challenging problem, and to significantly advance our knowledge in such important flows these instabilities will be investigated in a combined manner encompassing experiments, theory and numerical simulations. Such a holistic approach will enable us to understand the underlying mechanisms of those instabilities and to develop accurate criteria for their prediction far in advance of what we could achieve with either approach separately. A deep understanding of the mechanisms generating elastic instabilities and subsequent transition to elastic turbulence is crucial from a fundamental point of view and for many important practical applications involving engineered complex fluids, such as the design of microfluidic mixers for efficient operation under inertialess flow conditions, or the development of highly efficient micron-sized energy management and mass transfer systems.This research proposal will create a solid basis for the establishment of an internationally-leading research group led by the PI studying flow instabilities and elastic turbulence in complex fluid flows."