T. von Larcher

GeoFlow: On the status of experimental preparation of spherical gap flow experiments with central force field on International Space Station (ISS)

The GeoFlow experiment focus on convective flows in rotating spherical shells influenced by a central force field. To eliminate the unidirectional acceleration due to gravity on earth, these long-time experiments require microgravity environment on the International Space Station. While recent results of accompanying numerics are presented in [1, 2], here we present the actual status of experiment preparation.

A Stochastic Closure Approach for LES with Application to Turbulent Channel Flow

The integral conservation laws for mass, momentum and energy of a flow field are universally valid for arbitrary control volumes. Thus, if the associated fluxes across its bounding surfaces are determined exactly, the equations capture the underlying physics of conservation correctly and guarantee an accurate prediction of the time evolution of the integral mean values.

Towards a Stochastic Closure Approach for Large Eddy Simulation

We present a stochastic sub grid scale modeling strategy currently under development for application in Finite Volume Large Eddy Simulation (LES) codes. Our concept is based on the integral conservation laws for mass, momentum and energy of a flow field that are universally valid for arbitrary control volumes. We model the space-time structure of the fluxes to create a discrete formulation. Advanced methods of time series analysis for the data-based construction of stochastic models with inherently non-stationary statistical properties and concepts of information theory for the model discrimination are used to construct stochastic surrogate models for the non-resolved fluctuations. Vector-valued auto-regressive models with external influences (VARX-models) form the basis for the modeling approach. The reconstruction capabilities of the modeling ansatz are tested against fully three dimensional turbulent channel flow data computed by direct numerical simulation (DNS). We present here the outcome of our reconstruction tests.