Refine
Year of publication
- 2024 (5)
- 2023 (17)
- 2022 (11)
- 2021 (22)
- 2020 (28)
- 2019 (38)
- 2018 (18)
- 2017 (22)
- 2016 (22)
- 2015 (23)
- 2014 (13)
- 2013 (14)
- 2012 (9)
- 2011 (15)
- 2010 (18)
- 2009 (18)
- 2008 (12)
- 2007 (23)
- 2006 (21)
- 2005 (27)
- 2004 (16)
- 2003 (10)
- 2002 (8)
- 2001 (6)
- 2000 (4)
- 1999 (6)
- 1998 (5)
- 1997 (9)
- 1996 (5)
- 1995 (3)
- 1994 (4)
- 1993 (3)
- 1992 (2)
- 1991 (3)
- 1990 (1)
- 1989 (1)
- 1988 (6)
- 1987 (3)
- 1985 (7)
- 1984 (2)
- 1983 (2)
Institute
- Fachbereich Luft- und Raumfahrttechnik (482) (remove)
Has Fulltext
- no (482) (remove)
Language
- English (482) (remove)
Document Type
- Article (239)
- Conference Proceeding (182)
- Part of a Book (26)
- Book (15)
- Conference: Meeting Abstract (7)
- Doctoral Thesis (5)
- Conference Poster (2)
- Other (2)
- Patent (2)
- Preprint (1)
Keywords
- avalanche (6)
- solar sail (5)
- hydrogen (4)
- snow (4)
- GOSSAMER-1 (3)
- Hydrogen (3)
- MASCOT (3)
- Wind Tunnel (3)
- Drinfeld modules (2)
- Flight Test (2)
The Newtonian regime of a recent nonlocal extension of general relativity is investigated. Nonlocality is introduced via a scalar “constitutive” kernel in a special case of the translational gauge theory of gravitation, namely, the teleparallel equivalent of general relativity. In this theory, the nonlocal aspect of gravity simulates dark matter. A nonlocal and nonlinear generalization of Poisson’s equation of Newtonian gravitation is presented. The implications of nonlocality for the gravitational physics in the solar system are briefly studied.
High aerodynamic efficiency requires propellers with high aspect ratios, while propeller sweep potentially reduces noise. Propeller sweep and high aspect ratios increase elasticity and coupling of structural mechanics and aerodynamics, affecting the propeller performance and noise. Therefore, this paper analyzes the influence of elasticity on forward-swept, backward-swept, and unswept propellers in hover conditions. A reduced-order blade element momentum approach is coupled with a one-dimensional Timoshenko beam theory and Farassat's formulation 1A. The results of the aeroelastic simulation are used as input for the aeroacoustic calculation. The analysis shows that elasticity influences noise radiation because thickness and loading noise respond differently to deformations. In the case of the backward-swept propeller, the location of the maximum sound pressure level shifts forward by 0.5 °, while in the case of the forward-swept propeller, it shifts backward by 0.5 °. Therefore, aeroacoustic optimization requires the consideration of propeller deformation.
The utilization of phase change material (PCM) for latent heat storage and thermal control of spacecraft has been demonstrated in the past in few missions only. One limiting factor was the fact that all concepts developed so far envisioned the PCM to be applied as an additional capacitor, encapsulated in its own housing, leading to mass, efficiency and accommodation challenges. Recently, the application of PCM within the scan cavity of a GEOS type satellite has been suggested, in order to tackle thermal issues due to direct sun intrusion (Choi, M., 2014). However, the application of PCM in such complex mechanical structures is extremely challenging. A new concept to tackle this issue is currently under development at the FH Aachen University of Applied Sciences. The concept "Infused Thermal Solutions (ITS)" is based on the idea to 3D print metallic structures in their regular functional shape, but double walled with internal lattice support structures, allowing the infusion of a PCM layer directly into the voids and eliminating the need for additional parts and interfaces. Together with OHB System, FH Aachen theoretically studied the application of this technology to the Meteosat Third Generation (MTG) Infra-Red Sounder (IRS) instrument. The study focuses on the scan cavity and entrance baffling assembly (EBA) of the IRS. It consists of thermal analyses, 3D-redesign and bread boarding of a scaled and PCM infused EBA version. In the thermal design of the alternative EBA, PCM was applied directly into the EBA, simulating the worst hot case sun intrusion of the mission. By applying 4kg of PCM (to a 60kg baffle) the EBA temperature excursions during sun intrusion were limited from 140K to 30K, leading to a significant thermo-opto-elastic performance gain. This paper introduces the ITS concept development status.