Showing papers in "Aerospace Science and Technology in 2003"

TL;DR: In this paper, the authors highlight critical R&D needs for advanced TBC systems with a special focus on reduced thermal conductivity and life prediction needs, and highlight the need for reliable and predictable TBC performance.

TL;DR: In this article, an overview of the main results obtained on instabilities and pressure oscillations in segmented solid rocket motors is given. But the most important recent result inside ASSM and POP programs was the discovery of the parietal vortex shedding and the role of aluminum combustion on the instabilities.

TL;DR: In this paper, the authors applied the CIRA RANS flow solver by employing a large set of turbulence models, to typical aerodynamic applications for which certified experimental data are available in literature.

TL;DR: The use of recurrent neural networks for predicting the coefficient of lift $(C_Z)$ at high angle of attack is described, which is easy to incorporate in any commercially available rotor code.

TL;DR: In this article, high-resolution numerical simulations of aircraft wake vortex evolution and decay in different regimes and atmospheric conditions are presented, where the formation of coherent secondary vorticity structures that enclose the primary vortices is observed.

TL;DR: A review of theoretical and experimental results on stability and other unsteady properties of aircraft wakes can be found in this article, where the basic mechanisms responsible for the propagation and amplification of perturbation along vortices, namely the Kelvin waves and the cooperative instabilities, are first detailed.

TL;DR: In this article, the aeroelastic behavior of turbomachinery bladings in the time domain is analyzed using an automatic grid generation in which the used mesh is dynamically deformed so that it conforms with the deflected blades at every time step.

TL;DR: In this paper, a purely kinematic point positioning of satellites in low Earth orbit (LEO) based on single frequency GPS measurements is discussed, which makes use of a ionosphere-free combination of C/A code and L1 phase observations and can be employed with the majority of non-geodetic spaceborne GPS receivers.

TL;DR: In this paper, a helicopter H∞ flight control system is designed to improve its stability, maneuverability, and agility, and two helicopter flying quality indices, quickness index and phase delay margin, are adopted to test the robustness of helicopter H ∞ controller.

TL;DR: In this article, the authors present a summary of high-lift wing solutions and the constraints driving the high lift wing design for the Megaliner aircraft, which is based on the A380.

TL;DR: In this paper, surface interaction phenomena of both SiC-coated and uncoated C/C-SiC material of DLR's well known liquid siliconizing process (LSI) while exposing samples and structures to simulated and real space vehicle reentry conditions are investigated.

TL;DR: This study proposes a different composition of the performance index that incorporates the deviation from a reference flight path instead of a fuel parameter and shows that, depending on the scenario, two instruments are employed to a different extent in order to achieve a noise reduction.

TL;DR: In this paper, the simulation of an asymmetric landing case and typical ground maneuvers for large transport aircraft is presented, based on the work done in cooperation between DLR and Airbus in the flexible aircraft 2 project.

TL;DR: In this paper, the question of state variable feedback control of prototypical aeroelastic wing sections with structural nonlinearity has been addressed and a control law is designed based on the state-dependent Riccati equation technique.

TL;DR: In this article, experimental aerodynamic investigations on an airship configuration at angle of attack with special emphasis on the hull-fin region are reported, in particular visualizations of flow phenomena on both hull and fins are studied.

TL;DR: The evaluation of the computational effort shows that a real-time hardware realization can be carried out using off-the-shelf digital components.

TL;DR: Results indicate that the method SALSA is feasible and more suitable than SAGAT to evaluate prospectively future ATM-concepts with regards to their impact on safety, and a new method to measure SA in ATC, called SALSA.

TL;DR: In this article, the potential of oxide/oxide composites for applications in turbine engines as combustor walls is highlighted, and new processing routes based on liquid infiltration using alkoxides or reaction-bonding techniques are presented with the objective to develop non-oxidable CMC's at lower manufacturing cost than SiC/SiC composites.

TL;DR: In this article, the authors analyze type-III and type-IV shock-shock interactions and find that the most critical conditions occur when the supersonic jet is nearly perpendicular to the body surface.

TL;DR: In this article, a coherent anti-Stokes Raman spectroscopy (CARS) was used to investigate high pressure cryogenic liquid oxygen/gaseous hydrogen (LOX/GH 2 ) flames at pressures up to 6.5 MPa.

TL;DR: In this paper, two different materials and design approaches are discussed, namely local reinforcement of the titanium fan blades by using titanium matrix composites (TMCs) and by replacing the bulk titanium fan blade by fiber reinforced plastics (hybrid concept).

TL;DR: In this paper, noise reduction studies for aero engines are described in which DLR is involved, in which low noise fan design, active noise control using wall-flush loudspeakers as secondary sources, ANC using active stators as secondary source, and ANC using flow induced secondary sources at the rotor tips, reduction of low-pressure turbine noise, and flight tests for validation of add-on noise reduction devices.

TL;DR: In this paper, the first results obtained during the investigation of the transient ignition process in a cryogenic model rocket combustion chamber are reported, where the ignition of the propellants LOX and GH2 has been initiated with a pulsed laser and ignition and flame stabilization processes have been analyzed using high-speed visualization methods.

TL;DR: In this article, the authors discuss the recent progress achieved by research teams from both France and Germany in high pressure Oxygen/Hydrogen (O2/H2) combustion systems.

TL;DR: In this paper, a computational model updating (CMU) method was used to validate the finite element (FE) model of a civil four-engine aircraft using modal data obtained by ground vibration testing.

TL;DR: A model of the mental activities of en route controllers in air traffic control (ATC) is outlined, and a procedure for conflict resolution is described, supplementing the general model.

TL;DR: In this article, an automatic Vorticity Confinement procedure is proposed to conserve vorticity in the resolution of the compressible Euler or Navier-Stokes equations.

TL;DR: In this article, the feasibility of reducing the noise produced by aeronautical turbo engines by means of appropriate passive acoustic treatments applied directly to the exhausters is demonstrated, and some significant results are shown as well as some important findings for future investigation.

TL;DR: In this article, the authors present the results of a study done for the German Aerospace Center, DLR, to identify the required design capabilities in external hypersonic aerothermodynamics for future space transportation vehicles, where lessons learned from the latest German program on Technologies for Reusable Future Space Transportation Systems, TETRA, as well as experiences collected from past European technology programs and flight vehicles are taken into account.

TL;DR: In this article, the authors describe the computational work performed by five of the fifteen partners in the Brite-Euram project UNSI, for the prediction of static aeroelastic configurations and dynamic flutter response at transonic conditions, using advanced time-domain fluid-structure coupling methods.