CAREER: Automated physics-based distillation of coherent structures and mechanisms in unsteady and turbulent flows

Illinois Institute Of Technology, Chicago IL

Investigators

Abstract

Identifying and understanding the fundamental mechanisms that sustain unsteady and turbulent flows is important for ensuring accurate prediction and effective optimization and control across a broad range of applications, such as for reducing drag on aerodynamic vehicles, improving efficiency in wind energy harvesting devices, and improving patient outcomes via cardiovascular flows. While we have a good understanding of such mechanisms for simple flows, new tools will be required to obtain similar levels of understanding for a broader range of applications of real-world relevance. This project will develop methods that enable such mechanisms to be identified in an automated and unambiguous manner, with minimal data and computational requirements. These technical developments will be coupled with educational and outreach initiatives involving the research community, university students in coursework and research, K-12 students, and members of local community groups on Chicago's South Side. The proposed research will develop two central ideas to address the challenge identified above, with an overall goal of developing a methodology to isolate dominant coherent structures and mechanisms in an unambiguous, automated, and computationally efficient manner. The first idea involves applying sparsity-promoting methods to physics-based modeling tools to uncover minimal-physics models without needing the human insight and/or trial-and-error that would otherwise be required. The second idea considers methods to approximate the behavior of these mechanisms using analytic rather than numerical methods, leveraging ideas from wave-packet pseudo-spectral theory. This formulation in turn enables additional analysis methods conducive to studying a broader class of mechanisms, in particular allowing for highly nonlinear behavior to be modeled. To demonstrate their utility, these methods will be applied on a range of fluid flows, including incompressible and compressible parallel shear flows, flows with secondary mean flow components induced by sidewalls, and cardiovascular flows with more complex geometries. An improved ability to identify and manipulate the coherent structures that exist within turbulent flows can benefit a broad range of applications, with the potential to decrease friction drag on air, sea, and ground transport vehicles, increase the efficiency of wind turbines, and enhance understanding and treatment of cardiovascular diseases. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.