The proposed research will transform predictive capabilities of multiphase flows across the relevant length- and time-scales: from nanometres to kilometres, and from nanoseconds to hours, respectively, and will resolve fundamental and formidable research challenges that have remained unresolved for decades. The close synergy and integration between the partners in terms of theory, computation, and experiment, at all scales, is unprecedented.

Current multiphase flow research strategies either examine individual small length-scale phenomena in isolation (e.g. drop coalescence, bubble or drop detachment) without considering their influence on the global flow field and operational conditions, or examine global system properties (e.g. pressure drops) at the expense of examining individual local phenomena. Models for overall flow behaviour are often semi-empirical and do not relate the physical understanding or synergies across the length- and time-scales. Use of empirical correlations is never robust and can be distinctly dangerous when they are extrapolated outside the range of their validity.

Our synergistic, integrated Programme will advance the current state-of-the-art significantly by developing a unique predictive framework that offers:

• Numerical simulations that can pin-point, automatically, the largest sensitivities of the predictions to experimental data and/or equations used to model physical phenomena;
• Feedback loops from the simulations to the experiments, altering their design optimally to maximise prediction accuracy; this is absent in all previous and present simulation tools;
• Unparalleled simulation accuracy and efficiency, through parallelisation with 105-106 cores, to provide unprecedented resolution of the smallest length- and time-scales; this will minimise the dependence on empiricism and ‘closures’, as far as possible, and along with targeted experiments, aid in the rational development of the most reliable sub-grid models;
• Simulation of industrially-relevant flows on industrially-relevant length- and time-scales;
• Insight into the fundamentals of multiphase flows at all relevant scales leading to novel manufacturing routes for multiphase structured fluids, and equipment and process design;
• Ready-for-use predictive tools that can be assimilated easily within existing industrial codes/software, minimising the time-to-impact.

Our complementary skills and the flexibility afforded by the Programme will allow us to develop this framework, which will alter the research landscape of multiphase flows with an immediate and profound impact on a large number of diverse industrial applications; the latter will be accelerated and facilitated by our strong and long-standing industrial partnerships. Though it might be considered high-risk, our skills and strong track-record in leading and planning large research programmes will minimise this risk.