Direct numerical simulations (DNS) have made significant contribution to our understanding of multiphase flows over the last two decades. As their use has increased, and increasingly complex systems are being examined, two major issues have emerged. The first is that in many situations small-scale features emerge that require excessive (and often unachievable) resolution. These features either emerge spontaneously as thin films or threads or due to the addition of new physics that takes place on time and length scales very different than those of the flow. The second issue is that the wealth of data generated by DNS now far outstrips what can be used in standard models for the average flow field. This project is aimed at addressing both issues through the following two objectives. (1) The use of embedded analytical description for accurate capture of topology changes in simulations of multiphase flows. The approach is based on the observation that many small-scale features (films, threads, boundary layers, etc.) have a relatively simple structure and can therefore be described relatively accurately by analytical or semi-analytical models that are evolved concurrently with the fully resolved larger-scale motion. In this project, earlier work of films and mass transfer will be extended to capture accurately the rupture of films and threads. (2) Explore the evolution of various advanced statistical ways to describe the topology of complex multiphase flows. Such quantities include the area concentration tensor, average surface tension effects, and others, yet to be determined. The goal is to establish how these quantities correlate with the structure of the flow, and to attempt to model their evolution. Particular attention will be focused on how these quantities change during topology changes, their influence on the overall evolution of the flow, and the importance of predicting rupture accurately. The numerical methods will be made available through an online repository, along with a thorough documentation of the methodology and the use of the codes.
Multiphase flows are critical in energy conversion, material processing, chemical industry, atmospheric processes, and living systems. Incremental improvement in the efficiency of such processes translates into billions of dollars in savings and new discoveries have the potential to transform whole industries. Computational studies will bring about both incremental and transformative changes in the management of multiphase systems. Educational material aimed at lowering the barrier to entry for new researchers will be developed and undergraduate students will be exposed to the area through research projects.
This project is partially funded by an CISE/ACI CIF21 Venture Fund for Software Reuse.
