des DFG-Sonderforschungsbereichs 393

Numerische Simulation auf massiv parallelen Rechnern

Zeit: Freitag, 18.10.2002, 11:00 Uhr
Ort: Reichenhainer Straße 70, B 202
Vortragender: Dr.-Ing. habil. Michael Breuer (Uni Erlangen-Nürnberg)
Thema: Large eddy simulation of turbulent flows

The presentation gives an introduction into the large eddy simulation (LES) technique. The fundamentals of LES are presented starting with Kolmogorov's energy cascade which leads to the basic concept of LES.

The filtering approach is explained separating the large energy-carrying vortices which can be directly computed (grid-scale) from the non-resolvable subgrid-scale structures which have to be modeled by a subgrid--scale model. The governing equations for LES are given and the most widely used subgrid-scale models are discussed.

Furthermore, the problem of defining appropriate boundary conditions is addressed. Different examples for LES computations are shown which demonstrate that LES is especially well suited for turbulent flows past bluff bodies which are in general very complicated, including complex phenomena such as separation, reattachment or vortex shedding.

One test case is the turbulent flow past a circular cylinder. The objective of these investigations was not to investigate the physical phenomena of this flow in detail but to study numerical and modeling aspects which influence the quality of LES solutions.

Finally, some technically more relevant applications are shown which demonstrate the capabilities of LES. At the end, an outlook towards future applications within coupled simulations (e.g. fluid-structure interaction or aeroacoustics) is given.

Das Seminar wird von Prof. Meyer geleitet. Interessenten sind herzlich eingeladen.

Gerd Kunert,