Mechanical and Civil Engineering Seminar

Mechanical and Civil Engineering Seminar Series

Title: Extreme Aerodynamics: Analysis and Control for Flight in Highly Gusty Conditions

Abstract: An air vehicle trying to operate in adverse weather or wakes of urban canyons and mountainous terrains would be hit by strong large-scale atmospheric disturbances. In such extreme aerodynamic conditions, flight control becomes a great challenge, if not impossible, due to the enormous transient forces that the vehicle experiences. Currently, encounters with these extreme flow phenomena limit operations of fixed and rotating wing aircraft, especially those that are small to medium in size. The present study is focused on the analysis, modeling, and control of extreme aerodynamic flows, with unsteadiness far larger in amplitudes than those considered in traditional aerodynamics on a time scale comparable to those of the flow instabilities. The high dimensionality, strong nonlinearity, and multi-scale properties of these extreme flows make systematic analysis and control a tremendous challenge. Without the reduction of the state variable dimension and extraction of dominant dynamics, the application of dynamical systems and control theory for flow control remains difficult. This talk will present modern approaches to model and control such complex fluid flows by leveraging data-driven techniques and high-performance computing. We in particular will discuss the use of unsupervised and supervised machine learning techniques and how they can be embedded in existing flow analysis techniques. Equipped with these toolsets, we extract the essential inertial manifolds of extreme aerodynamics to facilitate the development of sparse and reduced-order models to design flow control techniques. Some of the successes in characterizing, modeling, and controlling extreme aerodynamic flows will be presented, followed by discussions on open problems and outlooks.

Bio: Kunihiko (Sam) Taira is a Professor of Mechanical and Aerospace Engineering at UCLA working in the areas of unsteady aerodynamics and flow control using high-performance computing and data-driven analysis. Before joining his current institution, he was a faculty member at Florida State University. He received his B.S. from the University of Tennessee, Knoxville, and his M.S. and Ph.D. from the California Institute of Technology. He is the recipient of the 2013 Air Force Office of Scientific Research Young Investigator Award, the 2017 Office of Naval Research Young Investigator Award, and the 2022 Department of Defense Vannevar Bush Faculty Fellowship. He held visiting positions at the US Air Force Research Laboratory and Tokyo University of Science and has industry experience with the Research and Development division of Honda. He is an Associate Fellow of AIAA and serves as an associate editor for the AIAA Journal and the Theoretical and Computational Fluid Dynamics.

NOTE: At this time, in-person Mechanical and Civil Engineering Lectures are open to all Caltech students/staff/faculty/visitors.