Abstract

This study presents the results from detailed experiments of the two-phase pressurized flow behavior during the rapid filling of a large-scale pipeline. The physical scale of this experiment is close to the practical situation in many industrial plants. Pressure transducers, water-level meters, thermometers, void fraction meters, and flow meters were used to measure the two-phase unsteady flow dynamics. The main focus is on the water–air interface evolution during filling and the overall behavior of the lengthening water column. It is observed that the leading liquid front does not entirely fill the pipe cross section; flow stratification and mixing occurs. Although flow regime transition is a rather complex phenomenon, certain features of the observed transition pattern are explained qualitatively and quantitatively. The water flow during the entire filling behaves as a rigid column as the open empty pipe in front of the water column provides sufficient room for the water column to occupy without invoking air compressibility effects. As a preliminary evaluation of how these large-scale experiments can feed into improving mathematical modeling of rapid pipe filling, a comparison with a typical one-dimensional rigid-column model is made. Keywords: Experimentation, Large-scale pipeline, Unsteady flow, Two-phase flow, Air–water interface, Flow-regime transition

Abstract

Rockwell Collins France (RCF) radar department is currently developing, in close collaboration with TNO in The Hague, The Netherlands, a Frequency Modulated Continuous Wave (FMCW) radar sensor dedicated to Obstacle Warning function and potentially to air traffic detection. The sensor combines flood light illumination and digital beam forming to accommodate demanding detection and coverage requirements. Performances have been evaluated in flight tests and results prove that such a radar sensor is a good candidate for the Sense Function of Sense and Avoid Systems onboard UAV. © 2013 SPIE.

Abstract

dvanced Driver Assistance Systems (ADAS) are becoming ubiquitous, and gradually take over the role of human drivers in the vision of the automotive sector. Humans are different from most systems: while in general humans exhibit a much higher error rate when performing specific functions, they are also unmatched in their adaptability, and their ability to recognize patterns and anticipate on these. In this paper we derive temporal requirements on future ADAS operation, needed to at least match human driving behavior in dense traffic. We examine Adaptive Cruise Control and Automated Emergency Braking systems at highway speeds, derive temporal requirements, and show that in dense traffic situations intent communication has a significant benefit to improve systems operation. The resulting requirements will challenge ADAS developments in the coming years. cop. 2015 IEEE.

Abstract

The development of advanced driver assistance technology continues to proceed rapidly. Cooperative systems based on wireless communication are a specific form of advanced driver assistance that is currently evolving rapidly. A drawback in the development of such systems is that options for large scale field-testing and -development of these automated systems are limited. Traffic simulation however offers widespread options for testing. In this paper the effects of cooperative driving using cooperative adaptive cruise control (CACC) to influence congestion shockwaves are evaluated on a part of the Amsterdam freeway network. The effects of congestion shockwaves on a network scale can be different to uniform freeway sections due to interaction between varying traffic flows. The application of CACC to mitigate the negative effects of shockwaves on a network level are simulated and analysed in this research for varying levels of CACC penetration. The results are analysed on both a quantitative as well as qualitative level and give a deeper understanding into the possibilities of the mass application of CACC systems. © 2011 IEEE.

Abstract

CityMobil was an integrated project in the Sixth Framework Program of the European Union. The objective of the project was to achieve more effective organization of urban transport for more rational use of motorized traffic with less congestion and pollution, safer driving, a higher quality of living, and enhanced integration with spatial development. This objective was reached by developing integrated traffic solutions: advanced concepts for innovative autonomous and automated road vehicles for passengers and goods embedded in an advanced spatial setting. The project was split into two parts: (a) research and development and (b) demonstration. The primary aim of the research and development part was to identify, address, and, where possible, eliminate barriers that still blocked the large-scale implementation of automated transport systems in urban traffic. The heart of the demonstration part consisted of three large-scale implementations of automated transport systems in urban areas and a number of smaller showcases and demonstrations. CityMobil was a 5-year project that started in May 2006 and ended in December 2011. The project results were presented at a final conference in Brussels, Belgium. This paper provides an update of a paper presented in 2009 and includes an overview of the final CityMobil results. The detailed results are available on the CityMobil website: www.citymobil-project.eu.

Abstract

In this paper, the design and results of two cooperative driving applications are presented that both increase traffic flow on highways by reducing shockwave traffic jams and decrease the risk of head-on collisions. The first application is an advisory system based on vehicle-vehicle communication that showed positive results with a penetration level of 100% of equipped vehicles. The second application is both an advisory and automated system based on infrastructure-vehicle communication that showed positive results with a penetration level of 10%-30%.

Abstract

This paper presents an integrated vehicle model to simulate simultaneously the driver, powertrains, chassis, body, road condition, vehicle dynamics and the Active Suspension (AS) system with/without an energy harvesting module. The developed model is used to investigate the ride comfort and influences of energy harvesting AS system on the total energy consumption of battery Electric Vehicles (EVs) relative to EVs with a passive suspension system. Preliminary simulation results show that compared to EVs with a passive suspension system, the ones with AS system improve ride comfort, up to 31% reduction of the vehicle body acceleration RMS value, with an expense of higher energy consumption. This expense can be reduced to about 2.8% when using an energy harvesting AS system. Simulation results also demonstrate that the available energy for recuperation during the AS system operation is significant in relation to the regenerative braking energy of the propulsion system, up to approx. 70% on bumpy road surfaces.

Abstract

Road throughput can be increased by driving at small inter-vehicle time gaps. The amplification of velocity disturbances in upstream direction, however, poses limitations to the minimum feasible time gap. This effect is covered by the notion of string stability. String-stable behavior is thus considered an essential requirement for the design of automatic distance control systems, which are needed to allow for safe driving at time gaps well below 1 s. Using wireless inter-vehicle communications to provide real-time information of the preceding vehicle, in addition to the information obtained by common Adaptive Cruise Control (ACC) sensors, appears to significantly decrease the feasible time gap, which is shown by practical experiments with a test fleet consisting of six passenger vehicles. The large-scale deployment of this system, known as Cooperative ACC (CACC), however, poses challenges with respect to the reliability of the wireless communication system. A solution for this scalability problem can be found in decreasing the transmission power and/or beaconing rate, or adapting the communications protocol. Although the main CACC objective is to increase road throughput, the first commercial application of CACC is foreseen to be in truck platooning, since short distance following is expected to yield significant fuel savings in this case.

Abstract

This paper presents a reference architecture for interoperability testing of electric vehicles as well as their support equipment with the smart grid and the e-Mobility environment. Pan-European Electric Vehicle (EV)-charging is currently problematic as there are compliance and interoperability issues on different communication levels and among the different domains comprising the eMobility system. The discussed reference architecture is composed out of three layers that enable addressing a direct mapping of interfaces, functions and services, as well as real world actors and/or laboratory equipment. Utilizing this architecture enables cross-domain co-simulation for interoperability within the electric mobility and the smart grid environment. Given the future challenges that rise to interoperability testing and the fact that certain aspects are yet unknown or rarely defined, the discussed architecture presents a very modular and extendable approach. © 2015 IEEE.

Abstract

For conventional buses, based on the decades of their operational knowledge, public transport companies are able to optimize their cost of operation. However, with recent trend in the usage of electric buses, cost optimal operation can become challenging. In this paper an offline optimal charging strategy is developed to minimize the energy cost. This is done by exploiting the periodicity and predictable operation of the city buses. For effective usage of the developed offline strategy, the actual energy demand of the electric bus must be known a-priori, which can be demanding. In order to address this issue, a predictor is designed. The neural network based predictor is able to estimate the energy demand for the next day. Using this, three different optimal charging strategies are implemented. Initially, only the operational constraints are considered to ensure the completion of a trip, later, a more involved problems consisting of battery state of charge (SoC) constraints and temperature constraints are included for the second and third optimization problems, respectively. All the three approaches result in significant energy cost minimization when compared to the non-optimal strategy of charging the electric bus to the full capacity at every available opportunity. Additionally, for the second and third formulations, namely, SoC and temperature constraints, by using a qualitative aging approach, some enhancements in the battery health is observed when compared to the non-optimal charging strategy.