DDPS | Extreme Aerodynamics: Flow Analysis and Control for Highly Gusty Conditions

DDPS Talk date: March 28th, 2025

Speaker: Kunihiko (Sam) Taira (UCLA, http://www.seas.ucla.edu/fluidflow/)

Description: 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 flight/flow control remains difficult. This talk will present our research group’s recent efforts to model and control such complex fluid flows by leveraging data-driven techniques. 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 Taira is a Professor of Mechanical and Aerospace Engineering at UCLA working in unsteady aerodynamics and flow control using computational and data-driven approaches. Prior to 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 a recipient of the 2013 AFOSR Young Investigator Award, the 2017 ONR Young Investigator Award, and the 2022 DoD Vannevar Bush Faculty Fellowship. He is a Fellow of APS and an Associate Fellow of AIAA. He currently serves as an Associate Editor for Physical Review Fluids and has served as an Associate Editor for the AIAA Journal and the Theoretical and Computational Fluid Dynamics.

DDPS webinar: https://www.librom.net/ddps.html
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LLNL release number is: LLNL-VIDEO-2004492