The lecture introduces adjoint methods for fluid dynamics. The
adjoint equations for the Navier-Stokes equations describe
sensitivities of a certain quantity of interest (think of drag of
an air-foil for example) to a certain input parameter (think of the
profile of the air-foil). Classical sensitivity analysis would
assume a profile and vary for example the chamber thickness to
calculate the sensitivity. One change results in one
sensitivity. Instead of changing the thickness and probing the
drag the adjoint equations provide an equation to directly
calculate the sensitivity for changing all surface points of the
profile. The method is capable of calculating the sensitivities
of millions of parameters in one step. This comes of course with
an effort, but immediately pays off, when more than a handful
parameters are to be investigated. In this lecture, the method is
introduced and an application to a particularly simple example of
an optimisation of an Epidemiology model for the COVID-19 pandemic
presented, to illustrate the method. Then applications to several,
more complicated, fluid dynamical problems are discussed.
22/07/2020
The webinar can be reached at this Goggle Meet link:
meet.google.com/fyg-xgcy-uyh
at 11:30am (Italian time)
Joern Sesterhenn received his Ph.D 1995 at the ETH Zurich for a
dissertation on compressible Low Mach number flows. A after a
post doctorate at the University of Washington where he worked on
gravity currents, he was a researcher at TU Munich, working on
Hypersonic and channel flows. He was habilitated in 2004 and
became professor at the University of the Armed Forces in Munich
in 2006. From 2009 to 2019 he was Professor for Numerical Fluid
Dynamics at TU Berlin and is at the University of Bayreuth since
2020, where he hold the Chair for Mechanics and
Fluid-mechanics. His present research activities are compressible
jet flows. He studies areoacoustics and stability of starting
jets, explosive volcanic eruptions, impinging jets for cooling or
additive material technologies (coating) and sustainment of
turbulence in interstellar media by galactic jets. He uses
forward and adjoint direct Numerical simulation and started
experimental work recently.