Author: Marion Ewald

Im Fokus: DoktorandInnen des SFB am Institut für Analysis

Posted on by

In der Arbeitsgruppe Nichtlineare Partielle Differentialgleichungen haben wieder drei „SFB-Neuzugänge“ ihre wissenschaftliche Arbeit aufgenommen und sind zum Teil auch in der Lehre aktiv:

Julia Henninger, Niklas Knobel und Lukas Bengel. Nachträglich ein herzliches Willkommen!

Wolfgang Reichel betreut ihre wissenschaftliche Arbeit. Uns hat interessiert, was sie antreibt, und wie sie sich bei uns und in Karlsruhe eingelebt haben. Lesen Sie mehr zu Echos in Flüssigkeiten, Mikroresonatoren und mathematischen Kuchen.

Continue Reading →

In Focus: Ruoci Sun

Posted on by
R. Sun

R. Sun

About 80 scientists are united within our CRC to deal with wave phenomena. One of them is Ruoci Sun.

In December he joined our CRC as a postdoc in Xian Liao‘s Junior Research Group Nonlinear Helmholtz Equations. Despite the strict regulations he dared to come from Paris to Karlsruhe. We warmly welcome him!

And we would like to introduce him here with a short interview. Thank you for answering our curious questions…

Continue Reading →

Computational Photonics – Summer School 2020

Posted on by

From September 21-25, 2020 leading experts (see the list below) will speak about important concepts and recent developments in the field of computational methods. Our recent Summer School will be complemented by computer tutorials to provide insights into the implementation and performance of various algorithms. Have a look at the schedule. The summer school will be an online event due to the Covid-19 situation. We organize the event on-site but with a proper streaming of all the lectures and exercises. If the situation relaxes in September and the regulations will permit we do it as a hybrid event.

Continue Reading →

Waveguides – Modellansatz

Posted on by

H. Wind

Everybody has experimented with resonating frequencies in a bathtub filled with water. These resonant eigenfrequencies are eigenvalues of some operator which models the flow behavior of the water. Eigenvalue problems are better known for matrices. For wave problems, we have to study eigenvalue problems in infinite dimension. Like the eigenvalues for a finite dimensional matrix the spectral theory gives access to intrinsic properties of the operator and the corresponding wave phenomena.

Anne-Sophie Bonnet-BenDhia from ENSTA in Paris is in conversation with Gudrun Thäter about transmission properties in perturbed waveguides.  This is the third of three conversations recorded during the Conference on Mathematics of Wave Phenomena July 23-27, 2018 in Karlsruhe for the Modellansatz Podcast. Anne-Sophie is interested in wave guides: Optical fibers that can guide optical waves while wind instruments are guides for acoustic waves. Electromagnetic waveguides also have important applications.

Continue Reading →

Pattern Formation

Posted on by

If one puts a pan with a layer of oil on the hot oven in order to heat it up one observes different flow patterns over time: In the beginning it is easy to see that the oil is at rest and not moving at all. But if one waits long enough the still layer breaks up into small cells which makes it more difficult to see the bottom clearly. This is due to the fact that the oil starts to move in circular patterns in these cells. In our example the temperature difference between bottom and top of the oil gets bigger as the pan is heating up. For a while the viscosity and the weight of the oil keep it still. But if the temperature difference is too big it is easier to redistribute the different temperature levels with the help of convection of the oil.

This means that the system has more than one solution and depending on physical parameters one solution is stable while the others are unstable. Mariana Haragus, Professor in Besançon at the University of Franche-Comté, is doing research on this important question for engineers as well as mathematicians.

Gudrun Thäter was in conversation with her in the context of the Modellansatz Podcast about Bernard-Rayleigh problems: Where do these convection cells evolve in theory in order to keep processes on either side of the switch? This had been one of the interesting research topics at our 2018 Conference on Mathematics of Wave Phenomena.

Hear more…