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CATEGORIES:Isaac Newton Institute Seminar Series
SUMMARY:Resolvent-based estimation and control of turbulen
t shear flows - Aaron Towne (University of Michiga
n)
DTSTART;TZID=Europe/London:20220330T120000
DTEND;TZID=Europe/London:20220330T123000
UID:TALK171188AThttp://talks.cam.ac.uk
URL:http://talks.cam.ac.uk/talk/index/171188
DESCRIPTION:Flow estimation and control provide a path forward
toward achieving many important engineering objec
tives\, such as decreasing drag\, delaying flow se
paration and transition\, and reducing flow-genera
ted noise. While state estimation and control are
classical topics in dynamical systems and control
theory\, standard methods have several disadvantag
es when applied to turbulent flows\, including hig
h cost and restrictions in their ability to incorp
orate key physics. In this presentation\, I will d
escribe an alternative framework for optimal flow
estimation and control formulated in terms of reso
lvent operators obtained from the Navier-Stokes eq
uations\, which have been shown to efficiently des
cribe organized motions within turbulent flows. Th
e resolvent-based framework provides a hierarchy o
f methods for different tasks\, including space-ti
me statistical modeling\, flow-field reconstructio
n in the time domain\, real-time causal estimation
\, and control. When equivalent assumptions are ma
de\, the causal resolvent-based estimator and cont
roller reproduce the Kalman filter and LQG control
ler\, respectively\, but at substantially lower co
mputational cost. Unlike these methods\, the resol
vent-based approach can naturally accommodate forc
ing terms (nonlinear terms from Navier-Stokes) wit
h colored-in-time statistics\, which significantly
improves the accuracy of the estimates. Moreover\
, the use of the resolvent framework facilitates p
hysical interpretation of the mechanisms involved
in the estimation and control procedure in terms o
f coherent flow structures. The performance of the
resolvent-based methods is demonstrated using the
flow over a backward-facing step and a turbulent
channel flow. \;
LOCATION:Seminar Room 1\, Newton Institute
CONTACT:
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