Best Paper Award at KH2018

Felix Wolf from GSCE/TEMF has received the “Young Scientist Best Paper Award” of the Kleinheubacher Tagung on “Radio Science” which took place September 24-26, 2018. The prize has been awarded for the paper “Isogeometric Discretisations of the Electric Field Integral Equation” by Felix Wolf, Jürgen Dölz, Stefan Kurz and Sebastian Schöps. Continue reading →

A New Parareal Algorithm for Problems with Discontinuous Sources

We recently proposed a new Parareal algorithm for problems with discontinuous sources which are common in electrical engineering, e.g., when an electric device is supplied with a pulse-width-modulated signal. Our algorithm uses a smooth input for the coarse problem with reduced dynamics. In the new arXiv preprint 1803.05503 preprint an error estimates is derived that shows how the input reduction influences the overall convergence rate of the algorithm. The theoretical results are supported by numerical experiments, including an eddy current simulation of an induction machine.

New paper on MOR for nonlinear problems

Under the doi 10.3390/mca23010008 Felix Fritzen, Bernard Haasdonk, David Ryckelynck any myself have published a new paper on an algorithmic discussion of competing parametric model reduction techniques for nonlinear problems in Mathematical and Computational Applications. The Galerkin reduced basis (RB) formulation is presented, which fails at providing significant gains with respect to the computational efficiency for nonlinear problems. Renowned methods for the reduction of the computing time of nonlinear reduced order models are investigated. All approaches are applied to a simple uncertainty quantification of a planar nonlinear thermal conduction problem. The paper is free under CC BY 4.0.

New paper on isogeometric analysis of electrical machines

Computer Methods in Applied Mechanics and Engineering has accepted our paper on Isogeometric analysis and harmonic stator–rotor coupling for simulating electric machines with DOI 10.1016/j.cma.2018.01.047. The paper proposes Isogeometric Analysis as an alternative to classical finite elements for simulating electric machines. Through the spline-based discretisation it is possible to parametrise the circular arcs exactly, thereby avoiding any geometrical error in the representation of the air gap where a high accuracy is mandatory.

Update: get the paper for free before April 10, 2018 at authors.elsevier.com.

Recent Advances on Multiphysics Simulation of Accelerator Magnets within STEAM at CERN

New papers from the STEAM collaboration with CERN, presented at the 25th International Conference on Magnet Technology have been accepted for publication by IEEE

Article on fast isogeometric BEM is published

Our article on a fast isogeometric BEM for the three dimensional Laplace- and Helmholtz problems is online! You can get it here. Anyone clicking on this link before January 09, 2018 will be taken directly to the final version of our article on ScienceDirect. No sign up, registration or fees are required – one can simply click and read. Enjoy!

Recent publications on novel time domain methods

Three papers from us on novel methods for time domain simulation of electromagnetic phenomenas have been published last week:
  • ParaExp using Leapfrog as Integrator for High-Frequency Electromagnetic Simulations in: Radio Science. doi: 10.1002/2017RS006357.
  • Solving nonlinear circuits with pulsed excitation by multirate partial differential equations in IEEE Transactions on Magnetics. doi: 10.1109/TMAG.2017.2759701.
  • Parallel-in-time Simulation of Eddy Current Problems using Parareal in IEEE Transactions on Magnetics. doi: 10.1109/TMAG.2017.2763090.
Preprints can be found at arXiv.

First results on fast high-order IGABEM

We published a first preprint at arXiv on our research on Isogeometric BEM for Superconducting Cavities (DFG SCHO 1562/3-1 and KU 1553/4-1). In cooperation with the Computational Mathematics group in Basel we discuss the usage of higher order B-splines in view of regularity requirements, convergence of the solution within the domain and multipole compression techniques. Continue reading →

Book “Progress in Differential-Algebraic Equations” is online

IMG_3067.JPG The book “Progress in Differential-Algebraic Equations” is available online and has just been published on SpringerLink:
http://link.springer.com/book/10.1007/978-3-662-44926-4

This book contains the proceedings of the 8th Workshop on Coupled Descriptor Systems held March 2013 in the Castle of Eringerfeld, Geseke in the neighborhood of Paderborn, Germany. It examines the wide range of current research topics in descriptor systems, including mathematical modeling, index analysis, wellposedness of problems, stiffness and different time-scales, cosimulation and splitting methods and convergence analysis. In addition, the book also presents applications from the automotive and circuit industries that show that descriptor systems provide challenging problems from the point of view of both theory and practice.

The book contains nine papers and is organized into three parts: control, simulation, and model order reduction. It will serve as an ideal resource for applied mathematicians and engineers, in particular those from mechanics and electromagnetics, who work with coupled differential equations.