California Institute of Technology

Flow Control

Feedback is the principal mechanism by which animals and plants achieve robust and efficient performance in the face of uncertain and changing input. The principles of feedback have been used by engineers for centuries to control the behavior of systems without human intervention. The autopilot on a jetliner is but one of countless sophisticated control systems we rely on in our daily lives. Our research seeks to go beyond control of engineering systems to apply feedback to natural flow phenomena, such as instabilities and turbulence. Distributed sensing, actuation, and feedback are used to fundamentally alter the natural dynamics of complex unsteady and turbulent fluid flows. Reduced drag, reduced energy consumption, and quiet operation are but a few of the benefits that can be achieved through control. Future engineered systems will also exploit controlled flows to eliminate fundamental design constraints, broaden the design envelope, and to adapt the system in real time to radically changing conditions. Through the Caltech Center for Bioinspired Engineering, we focus on the theory and practice of closed-loop flow control in applications ranging from wind energy, aerodynamics and propulsion, and biomedical devices.


Tim Colonius

Professor Colonius develops and uses algorithms for simulation of complex, multiscale flow phenomena. Simulations can provide key insights into the mechanics of unsteady flows, including understanding of local and global instabilites, sources of sound, shock dynamics, and interactions with a disperse phase such as cavitaiton bubbles. The simulations also provide important data for reduced-order modeling efforts and control.