56,350 research outputs found
Geier
No full textStammtafel der Familie Geier... übergeben von Johann Seifert, J. U. C. Regenspurg, 171
Das halbe und das ganze Lernen: kurze Entgegenung auf die Kritik von Siegfried Jäger und Raimund Küchler an halbierten Lernbegriffen. In: Linguistische Berichte 42 (1976), S. 62 - 94
No full textGeier M, Hasse A, Jaritz P, Keseling G, Kroeger H, Schmitz U. Das halbe und das ganze Lernen: kurze Entgegenung auf die Kritik von Siegfried Jäger und Raimund Küchler an halbierten Lernbegriffen. In: Linguistische Berichte 42 (1976), S. 62 - 94. Linguistische Berichte. 1977;47:89-92
Framework in Agriculture on the Farm Level
No full textLife Cycle Assessment (LCA) is a method that can be used to assess the environmental impact of agriculture, but impact categories and the functional unit of classical LCA’s must be adapted to the specific agricultural production process. Serving as an example, the framework of a LCA of 18 grassland dairy farms covering three farming intensity levels and carried out in the Allgäu region in southern Germany is presented. By focussing on the chosen impact categories and the respective, suitable functional units, the specific needs and backgrounds of conducting an agricultural LCA are discussed in general.
aus: Haas, G. und Wetterich, F. und Geier, U. (2000) Framework in Agriculture on the Farm Level. International Journal of Life Cycle Assessment 5(6):345-348
A Dynamic Subfilter-scale Stress Model for Large Eddy Simulations Based on Physical Flow Scales
No full textWe propose a new definition of the length scale in an eddy-viscosity model for large-eddy simulations (LES). This formulation extends and generalizes a previous proposal [Piomelli, Rouhi and Geurts, Proc. ETMM10, 2014], in which the LES length scale was expressed in terms of the integral length-scale of turbulence determined by the flow characteristics and explicitly decoupled from the simulation grid; this approach was named Integral Length-Scale Approximation (ILSA). As in the original ILSA, the model coefficient was determined by the user, and required to maintain a desired contribution of the unresolved, subfilter scales (SFS) to the global transport. We propose a local formulation (local ILSA) in which the model coefficient is local in space, allowing a precise control over SFS activity as a function of location. This new formulation preserves the properties of the global model; application to channel flow and backward-facing step verifies its features and accuracy
Large-eddy simulation of a separated flow with a sub-filter scale model based on the integral length-scale
No full textA new sub-filter scale model for large-eddy simulations, which uses a length-scale proportional to the integral scale of the turbulence instead of the grid resolution to parametrize the modelled stresses, will be assessed in the prediction of the flow of a boundary-layer over a rough surface, which includes separation and reattachment
Ethnisierende Differenzierungen im Elementarbereich. Sprachstandserhebungsverfahren zwischen landes- und kommunalpolitischen Direktiven und situiertem eigenlogischen Vollzug
No full textKuhn M, Mai M. Ethnisierende Differenzierungen im Elementarbereich. Sprachstandserhebungsverfahren zwischen landes- und kommunalpolitischen Direktiven und situiertem eigenlogischen Vollzug. In: Geier T, Zaborowski KU, eds. Migration: Auflösungen und Grenzziehungen Perspektiven einer erziehungswissenschaftlichen Migrationsforschung. Wiesbaden: Springer Science + Business Media; 2015: 115-132
Near Wall PIV-Measurements on the Windward Slope of a Hill
No full textThe turbulent flow over periodic hills was measured near to the wall, using planar Particle-Image-Velocimetry (PIV) at high spatial resolution. Our focus is on the near wall turbulence structure on the windward slope of the hill. For large-eddy simulation (LES) we suspect that, if this was not predicted accurately, it affects the prediction of the velocity profiles over the hill crest which in turn will affect the recirculation length downstream of the hill. Regarding the time averaged velocities, we were able to resolve the linear viscous region of the boundary layer. The velocity distribution and also the Reynolds stress does not comply with the law of the wall as it is valid for a turbulent boundary layer at equilibrium
Energy dissipation and flux laws for unsteady turbulence
No full textDirect Numerical Simulations of spatially periodic unsteady turbulence show that the high Reynolds number scalings of the instantaneous energy dissipation rate and interscale energy flux at intermediate wavenumbers are qualitatively different from the well-known cornerstone scalings of equilibrium turbulence where and are time-dependent rms velocity and integral length-scales. Instead, they both scale as where and are length and velocity scales characterizing initial/overall unsteady turbulence conditions
Direct numerical simulation of turbulent Couette-Poiseuille flow with zero skin friction
No full textThe near-wall scaling of mean velocity U(y) is addressed for the case of zero skin friction on one wall of a fully turbulent channel flow. The present DNS results can be added to the evidence in support of the conjecture that U is proportional to √yw in the region just above the wall at which the mean shear dU/dy = 0
Real-space Manifestations of Bottlenecks in Turbulence Spectra
No full textAn energy-spectrum bottleneck, a bump in the turbulence spectrum between the inertial and dissipation ranges, is shown to occur in the non-turbulent, one-dimensional, hyperviscous Burgers equation and found to be the Fourier-space signature of oscillations in the real-space velocity, which are explained by boundary-layer-expansion techniques. Pseudospectral simulations are used to show that such oscillations occur in velocity correlation functions in one- and three-dimensional hyperviscous hydrodynamical equations that display genuine turbulence
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