Numerical Investigation of the Aerodynamic Properties of a Flying Wing Configuration

The numerical investigations of a generic UCAV configuration are presented. These investigations are part of the DLR internal project UCAV-2010. Compressible speed conditions are considered and presented. The DLR-F17E UCAV configuration is a flying lambda delta wing with sweep angle of 53° and varying leading edge radius. The flow field of this UCAV configuration is dominated by vortex structures and vortex-to-vortex interaction. The paper aims to give a comparison between numerical- and experimental investigations in order to gain a deeper understanding of the complex flow physics. Furthermore, it will highlight the influence of Mach- and Reynolds number change on the flow and the overall aerodynamic behavior of the configuration. The DLR TAU-Code is used to simulate the flow field, using an unstructured grid and the turbulence model of Spalart-Allmaras. Forces and moment measurements taken in the DNW-TWG, Göttingen, on the DLR-F17E configuration serve as the experimental basis to validate the numerical findings. Findings on the SACCON configuration serve as a comparison case aiming to show possible portability between different model scales but also to find analogies between low speed (M=0.15) and compressible speed (M=0.5) scenarios. This paper builds up upon the finding within the NATO/RTO AVT-161 Research Task Group on “Assessment and Control Predictions for NATO Air and Sea Vehicles” and its findings shall serve as a basis for further experimental investigations of medium to high speed wind tunnel experiments. Furthermore, this paper addresses the importance of understanding and the ability to predict controlled- and uncontrolled flow separation and the interaction of vortex systems in order to estimate the aerodynamic behavior within the entire flight envelope and to meet Stability- and Control needs

Transition manifolds of complex metastable systems: Theory and data-driven computation of effective dynamics

We consider complex dynamical systems showing metastable behavior but no local separation of fast and slow time scales. The article raises the question of whether such systems exhibit a low-dimensional manifold supporting its effective dynamics. For answering this question, we aim at finding nonlinear coordinates, called reaction coordinates, such that the projection of the dynamics onto these coordinates preserves the dominant time scales of the dynamics. We show that, based on a specific reducibility property, the existence of good low-dimensional reaction coordinates preserving the dominant time scales is guaranteed. Based on this theoretical framework, we develop and test a novel numerical approach for computing good reaction coordinates. The proposed algorithmic approach is fully local and thus not prone to the curse of dimension with respect to the state space of the dynamics. Hence, it is a promising method for data-based model reduction of complex dynamical systems such as molecular dynamics

Untersuchung der Wirbel-Aerodynamik an hoch gepfeilten Mehrfach-Deltaflügel-Konfigurationen

In Zukunft soll ein Schwerpunkt der Forschung im DLR Projekt Diabolo die systematische Untersuchung von Mehrfachdeltaflügelkonfigurationen sein. Untersucht werden soll der Ein-fluss der Grundrissform, Vorderkantenkontur und Strömungssteuerungselementen wie Strakes oder LEVCON Elementen (Leading Edge Vortex Control) auf die Wirbeltopologie und –aerodynamik. Diese Untersuchungen sollen sowohl im Trans- als auch im Überschall expe-rimentell und numerisch durchgeführt werden. Die Grundgeometrie wurde von Airbus Defence & Space bereitgestellt und ist Basis für ge-meinsame experimentelle und numerische Forschungen im Rahmen der DLR Projekte Me-phisto/Diabolo und Forschungsgruppen der NATO STO/AVT

Trait Psychopathy and Job Performance in Leadership Jobs

In a recent meta-analysis, O’Boyle, Forsyth, Banks, and McDaniel (2012) found a significant negative relationship between trait psychopathy and job performance, however effect sizes were rather low (rc = -.10; O’Boyle et al., 2012). Thus, there is reason to suspect that the dimensions of psychopathy may be differentially related to job performance. Further, interactions with other constructs may warrant closer consideration

A probabilistic algorithm for aggregating vastly undersampled large Markov chains

Model reduction of large Markov chains is an essential step in a wide array of techniques for understanding complex systems and for efficiently learning structures from high-dimensional data. We present a novel aggregation algorithm for compressing such chains that exploits a specific lowrank structure in the transition matrix which, e.g., is present in metastable systems, among others. It enables the recovery of the aggregates from a vastly undersampled transition matrix which in practical applications may gain a speedup of several orders of magnitude over methods that require the full transition matrix. Moreover, we show that the new technique is robust under perturbation of the transition matrix. The practical applicability of the new method is demonstrated by identifying a reduced model for the large-scale traffic flow patterns from real-world taxi trip data

Impact of Planform and Control Surfaces on the Vortical Flow Topology and Roll Stability of a Multi Delta Wing Configuration

The current investigations look at the vortical flow physics and aerodynamic performance of a generic sharp leading edge multi delta wing configuration. The work is part of the DLR project Diabolo looking at technologies and design requirements for next generation fighter aircraft. The core of the investigation is a common planform geometry to demonstrate the design capability needed. Based on the initial planform, several design tasks in different domains have to be conducted. The present paper is dealing with the aerodynamic task to evaluate the effect of vortex interaction over the configuration progressing from the forebody, strakes and main wing at symmetric and asymmetric on flow conditions. The focus is on the roll and pitch stability at medium to high angle of attack. The aim is to find a planform and control surface setup which effects the vortex interaction on the main wing in a way to provide a stable aerodynamic behavior without taking vertical and horizontal tail planes into consideration in the first place

The Coupled Cluster Method in Hamiltonian Lattice Field Theory: SU(2) Glueballs

The glueball spectrum within the Hamiltonian formulation of lattice gauge theory (without fermions) is calculated for the gauge group SU(2) and for two spatial dimensions. The Hilbert space of gauge-invariant functions of the gauge field is generated by its parallel-transporters on closed paths along the links of the spatial lattice. The coupled cluster method is used to determine the spectrum of the Kogut-Susskind Hamiltonian in a truncated basis. The quality of the description is studied by computing results from various truncations, lattice regularisations and with an improved Hamiltonian. We find consistency for the mass ratio predictions within a scaling region where we obtain good agreement with standard lattice Monte Carlo results.Comment: 13 pages, 7 figure

Deutsche zweiter Klasse? Eine verfassungs-, europa- und völkerrechtliche Analyse der Optionsregelung nach §§ 29/40b Staatsangehörigkeitsgesetz

"Deutschen mit "Doppelpass" droht 2013 erstmals der Verlust der deutschen Staatsangehörigkeit. Das betrifft jene Deutschen, die nach dem 31.12.1999 in Deutschland geboren sind, deren Eltern keine deutsche Staatsangehörigkeit haben. Sie müssen bis zu ihrem 23. Lebensjahr für die deutsche Staatsangehörigkeit optieren, um diese zu behalten. Ausnahmen gelten nur für Deutsche, die zugleich Staatsangehörige eines EU-Mitglieds oder der Schweiz sind. Die Studie zeigt auf, dass die Optionspflicht aus menschenrechtlicher Sicht in mehreren Aspekten problematisch ist." (Autorenreferat