Topics and Research Projects

One main research subject of the Institute of Fluid Mechanics and Engineering Acoustics deals with Helmholtz Resonators in a Turbulent Boundary Layer.

For industrial use, hollow chambers in a turbulent flow are frequently surveyed. Often in expansive experimental runs, various configurations are tested in order to fulfill design objectives.
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Large-scale sound reinforcement for speech and music is nowadays typically realised with line array systems. Their drive has to be optimised with respect to several degrees of freedom, e.g.arrangement, geometry, construction of the boxes and different boundary constraints, e.g. geometry of the auditory, areas that have to be avoided, available acoustic power. It is an ill-posed inverse problem ...
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The analysis of complex fluid mechanical phenomena is based on experimental and numerical analysis. Both approaches provide suitable data, but no complete and exactly matching picture of a flow, which is to be examined. Experimental data are usually incomplete, because not every state variable is accessible by measurements and numerical solutions are often affected by ...
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Our team combines the unique perspectives of high-performance computing and experimental biology to address the challenging question of how flying insects cope with turbulent perturbations in the surrounding air flow. This pluridisciplinary project assembles physics, numerical modeling and simulation with experimental biology.
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The aim of the project is the depth investigation of the processes of pulsating-detonative combustion. Essential for the technical application of pulsating combustion is a fast and reliable transition from deflagration to more efficient detonation (DDT). In the experiment, a reliable DDT was found for a special geometry, consisting of a chamber with a convergent-divergent nozzle. The numerical simulation finds the DDT at the narrowest cross section as a complex interaction of different phenomena, in particular flame acceleration and shock focusing, which in turn is consistent with the measured pressure data. The underlying phenomena are strongly dependent on the speed of sound, heat release and characteristics of the flame as well as the boundary and start conditions, thus on the mixture properties and the operating conditions.
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Gas flows transporting charged particles occur in different fields. Our focus are vacuum devices, where molecules are ionized to manipulate and analyze these. An important application is the mass spectrometry, which, in all its variations and extensions, is one of the work horses in chemical and biochemical research.

In such devices, particles, like complex biochemical molecules, are typically ionized under atmospheric conditions and transferred to low pressure conditions, whereby the gas is removed and intact ions of theses molecules in vacuum are obtained. This is the prerequisite for many accurate and detailed investigation methods. Ionization under atmospheric conditions, as in electrosprays, allows ionization of molecules which would be destroyed by other, more direct methods.

The vacuum transfer inevitably yields high speed flows over high pressure range, i.e. high speed sonic and supersonic flows. These take place in complex geometries dictated by the need to create special, appropriate electric fields to guide the ions, i.e. ion optics.
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