**THIS SEMINAR HAS BEEN POSTPONED**

THIS SEMINAR WILL BE RESCHEDULED AND NOTIFICATION EMAILS WILL BE SENT OUT REGARDING THE NEW DATE AND TIME

MECHANICAL AND AEROSPACE ENGINEERING DEPARTMENTAL SEMINARS:
THERMO FLUIDS SERIES

“Control and Estimation of Turbulent Shear Flows using Modal Analysis”
Mitul Luhar
Associate Professor and Henry Salvatori Early Career Chair
Department of Aerospace and Mechanical Engineering
University of Southern California
Wednesday, May 25, 2022
37-124, Eng. IV
Time: 11:00 am – 12:00 pm
Abstract: Modal analysis methods can serve as powerful tools in the development of
reduced-complexity models for fluid flows. This talk presents two applications of
modal analysis involving control and estimation of turbulent shear flows. First, we
consider the development of passive control techniques for wall-bounded flows. We
show that the drag reducing effect of sharkskin-inspired riblet surfaces is reproduced
by a limited number of high-gain modes obtained via resolvent analysis. This reduced
representation enables optimization of riblet geometry and provides insight into the
development of permeable materials for turbulence control. Next, we attempt
parameter estimation and flow reconstruction for stratified wakes from limited and
noisy measurements. We create a library of flow features from prior simulation data
using dynamic mode decomposition (DMD). We then use a stepwise regression
technique to sequentially identify DMD modes that best represent the measurements and calibrate their amplitudes. The
resulting sparse model enables flow reconstruction as well as estimation of Reynolds and Froude numbers for the object
that created the wake. We demonstrate successful estimation of wake properties using this approach from both point and
field measurements of velocity.

Biosketch: Mitul Luhar is Associate Professor of Aerospace and Mechanical Engineering at the University of Southern
California. Research in his group tackles control of wall-bounded turbulent flows and fluid-structure interactions. This
work combinates laboratory experiments and reduced complexity modeling. Mitul is the recipient of the National Science
Foundation CAREER Award and the Air Force Office of Scientific Research Young Investigator Award. Prior to joining
USC, Mitul was a Postdoctoral Scholar in the Graduate Aerospace Laboratories at Caltech. He earned his Ph.D. in Civil
and Environmental Engineering from MIT in 2012 and B.A. and M.Eng. degrees in Engineering from the University of
Cambridge in 2007.

For more information, please contact Prof. Taira at ktaira@seas.ucla.edu
All faculty, students, and guests are welcome to this event.
(Refreshments will be served.)