The Flying V is a long-range, flying-wing aircraft where payload and fuel both reside in a V-shaped, crescent wing with large winglets that double as vertical tail planes. The objective of this study is to maximize the lift-to-drag (L/D) ratio of the Flying V in cruise conditions, i.e. CL= 0.26, M = 0.85 and to investigate its off-design performance in high-subsonic conditions. This is done by manually modifying the design parameters that describe the outer mold line of the Flying V and assessing the aerodynamic performance by means of computational fluid dynamics. A 15-million cell, third-order MUSCL, Reynolds-Averaged Navier Stokes solver with the Menter SST turbulence model is used to estimate the aerodynamic coefficients. This numerical model is validated using the experimental data of the ONERA M6 wing. A new, CATIA-based, parametrization of the Flying V is the starting point of the design. Three manual design phases improve the aerodynamic performance while satisfying all constraints. Design modifications include an increase in camber and aft-loading of the wing around 40% of the semispan and improved airfoil sections on the outboard wing generating the required lift coefficient towards an elliptical lift distribution. The twist distribution at the wing-winglet junction is optimized to reduce wave drag. This has resulted in an improvement of L/D from 20.3 from previous studies to 24.2 for the final version, while reducing the cruise angle of attack from 5.2 to 3.6 degrees. The drag divergence Mach number is estimated at 0.925.@en

Ten years after the initial sketches of the Flying V were made, we intend to give an overview of the development of this concept until the present day. The Flying V is a new concept for an efficient aircraft. It is a pure flying wing which includes a V-shaped passenger cabin. In this work, we describe how the concept developed - from the first drawings, the reasoning behind the concept and the design of the planform geometry, to the introduction of a structural solution for the pressurized cabin, to the design of a family of aircraft, detailed investigations of handling qualities and the interior layout. As of today, the concept promises a 20% lower fuel burn than a conventional reference aircraft on the same mission with the same capacity and the same wingspan, assuming current manufacturing techniques and current engine technology. Research activities on the Flying V have been continuously increasing over the past decade. Projects are ongoing in fields such as aerodynamics, structures and manufacturing, flight dynamics and control, the environmental impact of the design, aircraft integration, noise, and airport operation.@en

A preliminary comparison of evacuation times of the Flying V and the Airbus A350-900 is presented in this study. A simple simulation tool based on the technique of cellular automata was created to model the evacuation process for different closed door configurations. Certification regulations state that the time to evacuate a civil aircraft in case of an emergency with half of all exit doors closed must be less than 90 seconds. The results of this study indicate that the shorter V shaped cabin has advantages over the longer conventional reference cabin for cases when passengers need to evacuate towards the front or the back of the aircraft. Disadvantages occur when the passengers in the V shaped cabin need to evacuate more towards one side (left or right wing) of the aircraft. A more detailed simulation model to further investigate these cases is currently created by the authors.@en

In the present paper a numerical implementation technique for the transformations of the Method of Dimensionality Reduction (MDR) is described. The MDR has become, in the past few years, a standard tool in contact mechanics for solving axially-symmetric contacts. The numerical implementation of the integral transformations of the MDR can be performed in several different ways. In this study, the focus is on a simple and robust algorithm on the uniform grid using integration by parts, a central difference scheme to obtain the derivatives, and a trapezoidal rule to perform the summation. The results are compared to the analytical solutions for the contact of a cone and the Hertzian contact. For the tested examples, the proposed method gives more accurate results with the same number of discretization points than other tested numerical techniques. The implementation method is further tested in a wear simulation of a heterogeneous cylinder composed of rings of different material having the same elastic properties but different wear coefficients. These discontinuous transitions in the material properties are handled well with the proposed method.@en

In this work an idea on how to efficiently use the volume inside a pure flying wing for commercial passenger transport was derived and a configuration proposal was made with this idea. This configuration was then compared with a reference aircraft. The idea is to arrange two cylindrical pressurized sections for the payload swept back in the shape of a V and place them inside the front section of a wing with the same sweep angle. The streamwise cut through the oblique pressurized section is flat and elliptical and thus, it fits efficiently into conventional airfoils. The cut of the pressurized section orthogonal to the leading edge however, is circular. This leads to an efficient structural solution as pressure can be preserved well in a cylindrical shape. The proposed configuration is called the Flying V. For this configuration transition and outer wings extend the span of the highly swept middle wing at a lower sweep angle to 65m. The Flying V was designed in this work with a capacity of 315 passengers in a two class layout for a cruise speed of Ma=0.85. The Airbus A350-900 has the same capacity and cruise speed and was chosen as a reference aircraft. Preliminary estimations made in this work indicate that the Flying V might have a benefit over the reference in terms of aerodynamics (10% higher L/D) and mass (2% lower empty weight). More qualitative arguments in favor of the Flying V which could be derived are the compactness and simplicity of the configuration (less parts, no high-lift devices, no fairings, straight lines) and the shielding of the engines from the ground (low noise). Remarkable is also the elliptical lift distribution of the naturally stable design using only a moderate wing twist and no reflexed camber lines. A radio controlled model of the Flying V was presented in this work to demonstrate these aerodynamic characteristics and support the estimations and simulations which were made.@en

In this work a new concept for a commercial airplane is derived. The idea is to arrange two pressurized cylindrical sections for the payload swept back in the shape of a V and position them inside the front section of a single wing with the same sweep angle. The concept is designed for 315 passengers in a two class layout and is compared to the reference aircraft, Airbus A350-900. According to the preliminary estimations made in this paper a benefit of 10% in aerodynamics (L/D) and of 2% in mass can be expected of the new configuration over the reference. Further studies will be needed to validate these results and show the feasibility of the concept.@en

The dynamics of rolling on rough surfaces is of great interest from the viewpoint of functionality, noise production, and for the diagnostics of many technical systems, such as gears, ball bearings, wheel–rail, tire–road systems, and many others. The main difficulty in analyzing the rolling noise is solving the problem of contact between two elastic rough bodies. In this chapter, we use the method of dimensionality reduction for solving this problem.@en

Der Einfluss von kurzwelliger Oberflächenrauheit auf die Normalbeschleunigung in einem vereinfachten Rollkontakt wurde numerisch mithilfe der Methode der Dimensionsreduktion untersucht. Es wurde festgestellt, dass das Spektrum der Rauheit direkt im Spektrum der Normalbeschleunigung wiederzufinden ist, wobei eine zusätzliche Modulation auftritt, die durch das Verhältnis von Rollgeschwindigkeit zu Kontaktradius bestimmt wird. Die vorliegende Arbeit zeigt viele Parallelen zu einer Publikation von Ford und Thompson (2006), die ein sehr ähnliches eindimensionales Modell mit unabhängigen Federn verwendeten. Noch vor der Formalisierung der Methode der Dimensionsreduktion stellten sie fest, dass die Simulationsergebnisse mit dem eindimensionalen Modell sich sehr gut mit Ergebnissen von dreidimensionalen Randelemente-Simulationen decken und theoretischen Abschätzungen in vielen Fällen deutlich überlegen sind. Der vorgestellte Ansatz ist in vielen Richtungen erweiterbar, zum Beispiel ist in der vorliegenden Arbeit der Einfluss von langen Wellenlängen vernachlässigt worden, so dass die Resonanzfrequenz der Kugel und der rauheitsdominierte Bereich klar voneinander getrennt sind. Eine umfassendere Untersuchung mit einem realistischen Wellenlängenbereich und einem häufig auftretenden Roll-Off wäre sicherlich von großem Nutzen. Auch begrenzt das verwendete dynamische Modell die praktische Anwendbarkeit. Zukünftig könnte ein erweitertes Modell untersucht werden, bei dem die Kontaktkraftberechnung mit der Reduktionsmethode in einer FEM-Simulation oder Modalanalyse verwendet wird. Dies wäre von unmittelbarem Interesse für die Beschreibung von Vibration und akustischer Emission.@en

The present investigation is based on the assumption that the static coefficient of friction can be characterized roughly by the rms value of the surface gradient in the contact region. We numerically investigate the contact between a rigid, randomly rough surface and an elastic half-space and determine the dependence of the rms slope in the contact region on the normal force. For fractal surfaces with a Hurst exponent of H ≈ 1, the rms slope can be approximated very well by a logarithmic function of the normal force. Parameters of the approximation have been determined as functions of the Hurst exponent. The rms value of the slope always increases with the normal force, which indicates that the coefficient of friction should be an increasing function of the normal force.@en