Espen Åkervik, Mechanics 
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Large scale eigenvalue computations for flow stability 
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A lot can be gained by understanding the transition processes of fluid
flows, where the flow goes from laminar to turbulent. Flow stability
deals with the first part of this process, where small disturbances are
studied as they evolve with time. Specifically the spatially evolving
flat plate boundary layer flow is studied. Central to flow stability is
the computation of eigenvalues of the discretized linearized
Navier-Stokes equations. These equations describe the conservation of
mass and momentum. In their full version these equations form a high
dimensional system once discretized, rendering the eigenvalue problem
intractable for the standard QR method. To this end we use Krylov
subspace iterations together with the Arnoldi method to compute the
eigenmodes from which the stability characteristics of the
flow is analyzed.