- Independent Research Units
Independent Research Units
The main research interests are the structure and dynamics of hydrogen bonded, neutral clusters: methanol, ammonia, and water. The speciality of the group is the size selection of the clusters. Up to n=12 this is carried out by momentum transfer in collisions with rare gas atoms. For large clusters, the method of doping the clusters with sodium is applied. With these clusters ambitious spectroscopic experiments as well as scattering and dissociation processes have been measured. Very recently the transition to crystalline ice was observed at n=475.
Many Systems in nature, especially complex systems, are characterized by several or even many typical length scales where different physical mechanisms are important. Dynamics on length scales inbetween the extrema of these characteristics is called "mesoscopic".
Examples of systems we study are electronic nano-structures with dynamics inbetween quantum and classical mechanics but also the wave propagation in correlated, weakly disordered media on length scales below the mean free path but above the wavelength and the intrinsic scales of the medium.
We explore universal mechanisms that lead to extreme events in systems that are so diverse as the electron dynamics in semiconductors, the sound transmission through turbulent media and the propagation of tsunamis in the ocean.
The research of our group focusses on the nature of turbulent flows, in particular, the physics of turbulent thermal convection. This includes the investigation of natural, forced and mixed convection; coherent flow structures, boundary layer structures, small-scale turbulence in buoyancy-driven flows; the influence of rotation, non-Oberbeck-Boussinesq effects, non-monotonic fluid properties, wall roughness and domain geometry on turbulent convection. Apart from the physics of turbulence itself, we are also interested in the numerical issues and aspects of turbulence simulations.
Research interests in natural and applied sciences and engineering include in particular the large-scale oceanic circulation, wind chill effects in hot and cold regions, supergranulation in the solar upper convective zone, heat and mass transfer in nanofluids, surface-tension-driven convection and vibration-induced convection in low gravity, improvement of the efficiency of technological heating and cooling processes, control of ventilation processes in living quarters and in transport.