Fak. 5 Verkehrs- und Maschinensysteme

1155 Items

Recent Submissions
Compressible starting jet: pinch-off and vortex ring–trailing jet interaction

Peña Fernández, Juan José ; Sesterhenn, Jörn (2017)

The dominant feature of the compressible starting jet is the interaction between the emerging vortex ring and the trailing jet. There are two types of interaction: the shock–shear layer–vortex interaction and the shear layer–vortex interaction. The former is clearly not present in the incompressible case, since there are no shocks. The shear layer–vortex interaction has been reported in the lit...

Design, analysis, and control of a cable-driven parallel platform with a pneumatic muscle active support

Zhao, Xingwei ; Zi, Bin ; Qian, Lu (2017)

The neck is an important part of the body that connects the head to the torso, supporting the weight and generating the movement of the head. In this paper, a cable-driven parallel platform with a pneumatic muscle active support (CPPPMS) is presented for imitating human necks, where cable actuators imitate neck muscles and a pneumatic muscle actuator imitates spinal muscles, respectively. Analy...

Statistics of fully turbulent impinging jets

Wilke, Robert ; Sesterhenn, Jörn (2017)

Direct numerical simulations (DNS) of subsonic and supersonic impinging jets with Reynolds numbers of 3300 and 8000 are carried out to analyse their statistical properties with respect to heat transfer. The Reynolds number range is at low or moderate values in terms of practical applications, but very high regarding the technical possibilities of DNS. A Reynolds number of 8000 is technically re...

[Book review:] Jozef Wilczynski (1983): Comparative Industrial Relations. London: Macmillan

Wilpert, Bernhard (1986)

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[Book review:] Kenyon B. De Greene, The Adaptive Organization: Anticipation and Management of Crisis, New York: Wiley, 1982

Wilpert, Bernhard (1984)

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Inside Story: Inside IDE

Wilpert, Bernhard (1981)

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A Comparative Study of Accident and near Miss Reporting Systems in the German Nuclear Industry and the Norwgian Offshore Industry

Ringstad, Arne Jarl ; Szameitat, Steffen (2000)

A basic assumption in modern safety management is that accidents are preventable through effective feedback control; i. e. through mechanisms by which information about accidents and near misses is utilised as a basis to increase the level of safety. In spite of their popularity, however, previous research has shown that it is frequently difficult to make Accident and Near Miss Analysis Systems...

Die akustischen Randbedingungen perforierter Wandauskleidungen in Strömungskanälen

Schulz, Anita (2019)

Perforierte, schallabsorbierende Wandauskleidungen werden vielfach in Strömungskanälen, z. B. Flugzeugtriebwerken, zur passiven Lärmminderung eingesetzt. Die komplizierte Wechselwirkung zwischen Schall und Strömung an der strukturierten schalldurchlässigen Wand findet in einer relativ dünnen Grenzschicht statt, so dass der Einfluss auf die Schallausbreitung in guter Näherung durch akustische Ra...

The interaction between a spatially oscillating jet emitted by a fluidic oscillator and a cross-flow

Ostermann, Florian ; Woszidlo, Rene ; Nayeri, Christian Navid ; Paschereit, Christian Oliver (2019)

This experimental study investigates the fundamental flow field of a spatially oscillating jet emitted by a fluidic oscillator into an attached cross-flow. Dominant flow structures, such as the jet trajectory and dynamics of streamwise vortices, are discussed in detail with the aim of understanding the interaction between the spatially oscillating jet and the cross-flow. The oscillating jet is ...

Aufmerksamkeitsfokus beim Bewegungslernen

Wähnert, Svetlana (2019)

Bei Bewegungsaufgaben mit Lernbedarf, scheint der Fokus auf den Umwelteffekt (externer Aufmerksamkeitsfokus) zu anderen Lernergebnissen zu führen als der Fokus auf den eigenen Körper (interner Aufmerksamkeitsfokus). Viele Studien konnten dabei eine Überlegenheit des externen Aufmerksamkeitsfokus aufzeigen. Die vorliegende Forschungsarbeit beinhaltet sowohl einen Grundlagen- als auch einen Anwen...

Properties of a sweeping jet emitted from a fluidic oscillator

Ostermann, Florian ; Woszidlo, Rene ; Nayeri, Christian Navid ; Paschereit, Christian Oliver (2018)

This experimental study investigates the flow field and properties of a sweeping jet emitted from a fluidic oscillator into a quiescent environment. The aspect ratio of the outlet throat is 1. Stereoscopic particle image velocimetry is employed to measure the velocity field plane-by-plane. Simultaneously acquired pressure measurements provide a reference for phase correlating the individual pla...

The time-resolved natural flow field of a fluidic oscillator

Woszidlo, Rene ; Ostermann, Florian ; Nayeri, Christian Navid ; Paschereit, Christian Oliver (2015)

The internal and external flow field of a fluidic oscillator with two feedback channels are examined experimentally within the incompressible flow regime. A scaled-up device with a square outlet nozzle is supplied with pressurized air and emits a spatially oscillating jet into quiescent environment. Time-resolved information are obtained by phase-averaging pressure and PIV data based on an inte...

Phase-Averaging Methods for the Natural Flowfield of a Fluidic Oscillator

Ostermann, Florian ; Woszidlo, Rene ; Nayeri, Christian Navid ; Paschereit, Christian Oliver (2015)

The presented study examines various methods for phase averaging the naturally oscillating flowfield of a scaled-up fluidic oscillator. No external trigger is employed to control the oscillation of the flow. Mathematical and signal conditioning approaches for phase averaging the data are categorized and described. The results of these methods are evaluated for their accuracy in capturing the na...

Impact detection using a machine learning approach and experimental road roughness classification

Gorges, Christian ; Öztürk, Kemal ; Liebich, Robert (2018)

First, this publication presents the experimental validation of a road roughness classification method. Second, an impact detection strategy for two-wheeled vehicles is proposed including a classification of service loads, mild special events, and severe special events. The methods presented utilise the vehicle’s onboard signals to gather field data. The modular road roughness classification sy...

Road classification for two-wheeled vehicles

Gorges, Christian ; Öztürk, Kemal ; Liebich, Robert (2018)

This publication presents a three-part road classification system that utilises the vehicle's onboard signals of two-wheeled vehicles. First, a curve estimator was developed to identify and classify road curves. In addition, the curve estimator continuously classifies the road curviness. Second, the road slope was evaluated to determine the hilliness of a given road. Third, a modular road profi...

Customer loads of two-wheeled vehicles

Gorges, Christian ; Öztürk, Kemal ; Liebich, Robert (2017)

Customer usage profiles are the most unknown influences in vehicle design targets and they play an important role in durability analysis. This publication presents a customer load acquisition system for two-wheeled vehicles that utilises the vehicle's onboard signals. A road slope estimator was developed to reveal the unknown slope resistance force with the help of a linear Kalman filter. Furth...

Contact electrification in aerosolized micron-sized solid particles: dependence upon size, chemical composition and gas properties

Alois, Stefano (2018)

Contact electrification is ubiquitously present in our everyday life and acquires significant importance for micron scale particles, where it may be of considerable use in order to prevent/promote charging in a variety of practical applications. Despite being widely studied, a complete understanding of the charge transfer mechanisms is still lacking. In this work, contact electrification of ae...

Control of secondary flow structures on a highly loaded compressor cascade

Zander, Vincent ; Nitsche, W. (2013)

This paper presents detailed flow-field measurements for a compressor cascade equipped with synthetic jet actuators for active flow control. The synthetic jets are mounted on the cascade sidewall and the suction side surface of the blade to reduce the total pressure loss caused by strong secondary flow structures developing in the passage. There are certain articles reporting that synthetic jet...

Active flow control by means of synthetic jets on a highly loaded compressor cascade

Zander, Vincent ; Hecklau, Martin ; Nitsche, W. ; Huppertz, A. ; Swoboda, M. (2011)

This article presents the potential of active flow control to increase the aerodynamic performance of highly loaded turbomachinery compressor blades. Experimental investigations on a large-scale compressor cascade equipped with 30 synthetic jet actuators mounted to the sidewalls and the blades themselves have been carried out. Results for a variation of the inflow angle, the jet amplitude, and ...

On the Relation Between Reliance and Compliance in an Aided Visual Scanning Task

Wiczorek, Rebecca ; Meyer, Joachim ; Günzler, Torsten (2012)

Alarms, alerts, and other binary cues affect user behavior in complex ways. One relevant distinction is the suggestion that there are two different responses to alerts – compliance (the tendency to perform an action cued by the alert) and reliance (the tendency to refrain from actions as long as no alert is issued). An experiment tested the dependence of the two behaviors on the Positive and Ne...