TY - JOUR A1 - Götten, Falk A1 - Havermann, Marc A1 - Braun, Carsten A1 - Marino, Matthew A1 - Bil, Cees T1 - Wind-tunnel and CFD investigations of UAV landing gears and turrets – Improvements in empirical drag estimation JF - Aerospace Science and Technology N2 - This paper analyzes the drag characteristics of several landing gear and turret configurations that are representative of unmanned aircraft tricycle landing gears and sensor turrets. A variety of these components were constructed via 3D-printing and analyzed in a wind-tunnel measurement campaign. Both turrets and landing gears were attached to a modular fuselage that supported both isolated components and multiple components at a time. Selected cases were numerically investigated with a Reynolds-averaged Navier-Stokes approach that showed good accuracy when compared to wind-tunnel data. The drag of main gear struts could be significantly reduced via streamlining their cross-sectional shape and keeping load carrying capabilities similar. The attachment of wheels introduced interference effects that increased strut drag moderately but significantly increased wheel drag compared to isolated cases. Very similar behavior was identified for front landing gears. The drag of an electro-optical and infrared sensor turret was found to be much higher than compared to available data of a clean hemisphere-cylinder combination. This turret drag was merely influenced by geometrical features like sensor surfaces and the rotational mechanism. The new data of this study is used to develop simple drag estimation recommendations for main and front landing gear struts and wheels as well as sensor turrets. These recommendations take geometrical considerations and interference effects into account. Y1 - 2020 U6 - https://doi.org/10.1016/j.ast.2020.106306 SN - 1270-9638 VL - 107 IS - Art. 106306 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Meliß, Michael A1 - Neskakis, A. A1 - Usbeck, S. A1 - Wagner, L. A1 - Wiediger, Jürgen T1 - Wind-PV-Hybridsystem an der FH Aachen/Jülich JF - Energiewirtschaftliche Tagesfragen. Jg. 44 (1994), H. 9 (special) Y1 - 1994 SN - 0720-6240 SP - 34 EP - 40 ER - TY - JOUR A1 - Gerhardt, Hans Joachim T1 - Wind- und Temperatureinflüsse bei der Planung von Entrauchungseinrichtungen JF - VFDB-Zeitschrift : Forschung, Technik und Management im Brandschutz. 55 (2006), H. 3 Y1 - 2006 SN - 0042-1804 SP - 115 EP - 121 ER - TY - JOUR A1 - Jung, Alexander A1 - Müller, Wolfram A1 - Staat, Manfred T1 - Wind and fairness in ski jumping: A computer modelling analysis JF - Journal of Biomechanics N2 - Wind is closely associated with the discussion of fairness in ski jumping. To counter-act its influence on the jump length, the International Ski Federation (FIS) has introduced a wind compensation approach. We applied three differently accurate computer models of the flight phase with wind (M1, M2, and M3) to study the jump length effects of various wind scenarios. The previously used model M1 is accurate for wind blowing in direction of the flight path, but inaccuracies are to be expected for wind directions deviating from the tangent to the flight path. M2 considers the change of airflow direction, but it does not consider the associated change in the angle of attack of the skis which additionally modifies drag and lift area time functions. M3 predicts the length effect for all wind directions within the plane of the flight trajectory without any mathematical simplification. Prediction errors of M3 are determined only by the quality of the input data: wind velocity, drag and lift area functions, take-off velocity, and weight. For comparing the three models, drag and lift area functions of an optimized reference jump were used. Results obtained with M2, which is much easier to handle than M3, did not deviate noticeably when compared to predictions of the reference model M3. Therefore, we suggest to use M2 in future applications. A comparison of M2 predictions with the FIS wind compensation system showed substantial discrepancies, for instance: in the first flight phase, tailwind can increase jump length, and headwind can decrease it; this is opposite of what had been anticipated before and is not considered in the current wind compensation system in ski jumping. Y1 - 2018 U6 - https://doi.org/10.1016/j.jbiomech.2018.05.001 SN - 0021-9290 IS - 75 SP - 147 EP - 153 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Schürmann, Wilhelm T1 - Wilhelm Schürmann JF - Kunstforum International N2 - Geboren 1946, lebt und arbeitet in Aachen. Studium der Chemie an der Technischen Hochschule Aachen. Danach als freiberuflicher Photograph tätig für verschiedene Tageszeitungen. Seit 1972 Lehrer für Photographie am Reiff Museum der TH-Aachen, Institut für Architektur. Seit 1973 Dozent für Photographie an der Volkshochschule Aachen. Ende 1973 Gründung der Galerie Lichttropfen in Aachen. Organisator zahlreicher Ausstellungen historischer und zeitgenössischer Photographie im In- und Ausland. Y1 - 1976 N1 - Fotografien VL - 1976 IS - 18 SP - 151 EP - 156 PB - Kunstforum International CY - Köln ER - TY - JOUR A1 - Wollert, Jörg T1 - Wieviel Echtzeit kann Windows? JF - IEE : elektrische Automatisierung und Antriebstechnik Y1 - 1997 SN - 1434-2898 VL - Jg. 42 IS - Nr. 9 SP - 30 EP - 37 ER - TY - JOUR A1 - Jochim, Haldor E. T1 - Wieviel dürfen Verspätungsgarantien kosten? JF - Verkehrswissenschaftliche Tage der Hochschule für Verkehrswesen "Friedrich List" in Dresden / Technische Universität Dresden, Fakultät Verkehrswissenschaften Y1 - 2003 N1 - 19. Verkehrswissenschaftliche Tage Dresden, 22. September 2003 ER - TY - JOUR A1 - Mang, Thomas T1 - Wiederverwertung von Kunststoff-Verbundmaterial JF - Chemie und Technologie makromolekularer Stoffe. 16. Kolloquium: 20. November 1998 an der FH Aachen, Fachbereich Chemieingenieurwesen Y1 - 1998 N1 - FH-Texte 69. Fachhochschule SP - 191 EP - 213 PB - Fachhochschule Aachen CY - Aachen ER - TY - JOUR A1 - Fredebeul-Krein, Markus A1 - Freytag, Andreas T1 - Wie umfassend ist die Liberalisierung der Märkte für Telekommunikationsdienste? : Eine kritische Bewertung des WTO-Abkommen. / Markus Fredebeul-Krein ; Andreas Freytag JF - Lernort Multimedia / hrsg. von Herbert Kubicek ... Y1 - 1998 SN - 3-7685-3297-6 N1 - Jahrbuch Telekommunikation und Gesellschaft ; 6. 1998 SP - 318 EP - 325 PB - v. Decker CY - Heidelberg ER - TY - JOUR A1 - Thielemann, Frank A1 - Lüdtke, C. T1 - Wie sich Logistikunternehmen ihren Platz sichern können JF - Deutsche Verkehrs-Zeitung (DVZ) (1999) Y1 - 1999 SN - 0342-166X SP - 42 EP - 42 ER -