Mit dem Promotionspreis sollen die herausragenden Leistungen des wissenschaftlichen Nachwuchses sowie der wissenschaftliche Fortschritt, der mit der Dissertation erreicht wurde, hervorgehoben werden. Darüber hinaus soll durch die Preisverleihung auf die Vereinbarkeit von Promotion und Lehre bzw. Qualitätsmanagement im Netzwerk QSL aufmerksam gemacht werden.

GAMM Juniors sind DoktorandInnen oder junge Postdocs, die eine exzellente Masterarbeit oder Dissertation in der Angewandten Mathematik oder in der Mechanik geschrieben haben. Sie werden für 3 Jahre nominiert.

From the abstract:

In this contribution semi-explicit time integration of the magneto-quasistatic approximation of Maxwell’s equations is discussed. Space-discretization of the eddy-current problem results in a nonlinear differential-algebraic system. The eddy-current regions are described by (nonlinear) differential equations and the remainder (e.g. air) is typically modeled by a linear algebraic system. We apply a domain substructuring such that the conductive and nonconductive domains are treated separately by the time integrator. The conductive domain is solved explicitly in time such that parallelization can easily be exploited. The numerical stability of the explicit time integration scheme requires small time step sizes according to a Courant-Friedrich-Levi stability criterion, but at relatively low computational costs due to the explicit update scheme. Numerical results show the feasibility of this approach. In particular, a higher order half-explicit time integration scheme with extended stability region is shown to be very efficient.

• KH2011 Website

Modeling electric circuits that contain magnetoquasistatic (MQS) devices leads to a coupled system of differential-algebraic equations (DAEs). In our case, the MQS device is described by the eddy current problem being already discretized in space (via edge-elements). This yields a DAE with a properly stated leading term, which has to be solved in the time domain. We are interested in structural properties of this system, which are important for numerical integration. Applying a standard projection technique, we are able to deduce topological conditions such that the tractability index of the coupled problem does not exceed two. Although index-2, we can conclude that the numerical difficulties for this problem are not severe due to a linear dependency on index-2 variables.

I am on vacation in Sønder Stenderup, Denmark: great weather, a nice beach and the sea.

Back on August, 8th.

The talk deals with multiscale models from electrical engineering, i.e., the electric network, the magnetoquasistaic field device and the drift-diffusion model of a semiconductor. Their structure, coupling and DAE-index are analyzed and furthermore multirate time-integration methods for the coupled problem are discussed. This is in particular the multirate Schur complement with an energy-based update scheme and the dynamic iteration approach. It will be shown by numerical examples that their application reduces significantly the computational costs in coupled simulations compared to the standard single-rate approach.

Official Announcement of K.U. Leuven.

The talk discusses (higher order) co-simulation in applications from electrical engineering, in particular electric networks coupled to distributed field and semiconductor models. The key is the representation of latent problem parts by reduced order models that are iteratively fitted (by waveform relaxation). This weakens the coupling and increases the efficiency of the coupled simulation. The convergence and stability of the method are analyzed, especially with respect to higher order time-integration.