CSAR Noon Seminar
Kalyan Nakshatrala, UIUC/CEE
DATE: Wednesday, April 6, 2005
TIME: 12:00 Noon
PLACE: 2240 DCL
1304 W. Springfield Ave., Urbana, IL
TITLE: Stability of Coupling Algorithms
ABSTRACT
In this talk, we discuss the stability of coupling algorithms that are
commonly used to solve multiphysics problems (e.g. fluid-structure
interaction (FSI)). We show that some popular coupling algorithms are
not always stable, and in some cases they are unconditionally
unstable. We present stability results obtained by employing these
algorithms on a simple test problem. Some of the coupled simulation
results to be presented were obtained using the integrated
Rocstar simulation code. Though the main focus of the talk will
be on staggered schemes, we will also make some comments on monolithic
schemes. We present a new staggered coupling algorithm based on a
Lagrange multiplier technique in which the governing equations are
rewritten as a differential-algebraic equation (DAE). We will also
discuss constraint stabilization techniques and outline some of the
code changes required in Rocstar to implement such an
algorithm.