Fak. 5 Verkehrs- und Maschinensysteme

1159 Items

Recent Submissions
The physics of traffic and regional development

Helbing, Dirk ; Nagel, Kai (2004)

This contribution summarizes and explains various principles from physics which are used for the simulation of traffic flows in large street networks, the modelling of destination, transport mode, and route choice, or the simulation of urban growth and regional development. The methods stem from many-particle physics, from kinetic gas theory, or fluid dynamics. They involve energy and entropy c...

Incorporating within link dynamics in an agent-based computationally faster and scalable queue model

Agarwal, Amit ; Lämmel, Gregor ; Nagel, Kai (2017)

The growing pace of urbanization increases the need of simulation models to handle large-scale scenarios in reasonable time. The present study proposes a fast spatial queue model, which is anchored to an agent-based travel demand simulation framework. The existing queue model is extended to produce more realistic flow dynamics by introducing backward travelling holes to mixed traffic conditions...

Mind the price gap: How optimal emission pricing relates to the EU CO2 reduction targets

Kickhöfer, Benjamin ; Agarwal, Amit ; Nagel, Kai (2018)

From the transport economic literature, it is known that optimal pricing of (environmental) externalities improves the urban system. In contrast to theory-based optimal pricing strategies, real-world policy setting often follows so-called “backcasting” approaches where certain targets are set, and policy measures are implemented in order to reach those targets. An example for the latter approac...

Adaptive traffic signal control for real-world scenarios in agent-based transport simulations

Thunig, Theresa ; Kühnel, Nico ; Nagel, Kai (2019)

This study provides an open-source implementation of a decentralized, adaptive signal control algorithm in the agent-based transport simulation MATSim, which is applicable for large-scale real-world scenarios. The implementation is based on the algorithm proposed by Lämmer and Helbing (2008), which had promising results, but was not applicable to real-world scenarios in its published form. The ...

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...