41 research outputs found
Ground effect aerodynamics of racing cars
No full textWe review the progress made during the last thirty years on ground effect aerodynamics associated with race cars, in particular open wheel race cars. Ground effect aerodynamics of race cars is concerned with generating downforce, principally via low pressure on the surfaces nearest to the ground. The “ground effected” parts of an open wheeled car's aerodynamics are the most aerodynamically efficient and contribute less drag than that associated with, for example, an upper rear wing. Whilst drag reduction is an important part of the research, downforce generation plays a greater role in lap time reduction. Aerodynamics plays a vital role in determining speed and acceleration (including longitudinal acceleration but principally cornering acceleration), thus performance. Attention is paid to wings and diffusers in ground effect and wheel aerodynamics. For the wings and diffusers in ground effect, major physical features are identified and force regimes classified, including the phenomena of downforce enhancement, maximum downforce and downforce reduction. In particular the role played by force enhancement edge vortices is demonstrated. Apart from model tests, advances and problems in numerical modeling of ground effect aerodynamics are also reviewed and discussed
Image dataset for testing search and detection models
No full textThe TNO Human Factors Searchû2 image dataset consists of: a set of 44 high-resolution digital color images of different complex natural scenes, the ground truth corresponding to each of these scenes, and the results of psychophysical experiments on each of these images. The images in the Searchû2 dataset are a subset of a larger set that has been used in a visual search and detection experiment. Each scene (image) contains a single military vehicle that serves as a search target. The image dataset, an Excel file with the ground truth and observer data, and an extensive report describing the dataset are available on CD-ROM (requests by email to the first author). The dataset can be used to develop and validate digital metrics that compute the visual distinctness (contrast, conspicuity, or saliency) of targets in complex scenes, and models of human visual search and detection. The dataset has already been used in more than ten different studies in the literature, ranging from studies evaluating target detectability metrics to eye movement studies and attempts to model the human visual system. In addition to this work, eight other articles in this special section address the Searchû2 dataset
Ground effect aerodynamics research of racing cars
No full textThe research work conducted at the University of Southampton to analyze the ground effect aerodynamics of racing cars, are discussed. The ground effect aerodynamics of a racing car is characterized by features such as unsteady flow caused by suspension motion, movement of laminar to turbulent transition on surfaces closest to the road caused by chipping, vortex breakdown caused by large pressure gradient, turbulent wake caused by separation and shear layer instability, and ground boundary layer caused by local pressure gradient. The downforce generated by inverted wings increases as the height reduces from freestream and the magnitude of downforce starts falling after attaining maximum value. When the wing is brought closer to the ground, flow is accelerated which causes higher peak suction and higher pressure recovery demand, resulting in separation of boundary layer at the trailing edge of the suction surface at a critical height.</p
Onboarding opportunities for digital transformation: A design that quickly generates and shapes initiatives, and creates insight into their potential value
No full textThe European Airline is a big company that focuses on efficiency, sustainability and customer experience. Its department DS strives to make the company smarter and more efficient. They create value by experimenting with technologies and methodologies, delivering products into people’s hands, and transforming the way of working. My project was conducted as part of the Portfolio Management team within DS. The Portfolio Management team enables decision-making on priorities and guides delivery of value. On assignment for DS, my intent for the project was to design a concept that quickly generates and shapes initiatives, and creates insight into their potential value. The project started with framing the problem. During the literature study, I concluded that three studies were leading for this assignment. Elements of successful portfolio management are described by Cooper et al. (2001) as strategically aligned, maximum portfolio value and portfolio balance. This can be achieved by having a portfolio mindset, being agile, and focusing whilst generating and shaping initiatives (Kester et al., 2011). The elements of portfolio orientation and structuring proved to be essential for the assignment as well (Meskendahl, 2010). I conducted external interviews, during which elements from literature gained meaning within the assignment. I discovered how the elements of Cooper et al. (2001), Kester et al. (2011) and Meskendahl (2010) could be applied within the context of the problem. I concluded that all insights obtained could be divided between strategically aligned, maximum portfolio value, portfolio balance and portfolio mindset. The underlying drivers of these elements led me to define design criteria. Different combinations of ideas resulted in four concepts, including the frame toolbox concept. The frame toolbox aims to transform the Frame Creation method (Dorst, 2015) into a tangible product, where initiative owners feel supported in the rapid generation and shaping of initiatives with maximum value as output. I subsequently developed the frame toolbox concept within DS’ context by testing its assumptions, hypotheses and challenges. This testing resulted in finding a connection between the frame toolbox and DS’ resources. This iterative design process led to my final design of Blink. Blink is a digital toolbox that transforms all types of innovations into valuable focus points for product teams. It quickly exposes problems, themes, solutions, and opportunities to their core and maximizes their potential value. By implementing a simple step-by-step plan, new opportunities are shaped that align with DS’ strategy. Blink helps participants to reframe their mindset by discovering the drivers of initiatives to define where the “real” value lies. This value is assessed by the value check tool. Focus points are evaluated on desirability and viability; this clearly shows its potential value. A portfolio mindset among employees is ensured through Blink’s structure and transparency. Blink can be performed in small and large groups, both online and offline. It enables participants to act flexibly due to the short turnaround time. It prioritizes speed, as it focuses on rapid screening of the initiative’s potential value. This thesis describes the process I followed in developing Blink and concludes with an implementation plan, a final reflection, Blink’s limitations, and recommendations for future designs.Strategic Product Desig
De impedantie-transparante versterker met logarithmische vertragingslijnen.
No full textBeschreven is de bouw van en de metingen aan de impedantie-transparante versterker met logarithmische vertragingslijnen als echo-onderdrukker. Gebleken is dat de vervorming van spraak te groot is om de echo-onderdrukker continu in een telefooncircuit te plaatsen. Een mogelijke voortzetting van dit onderzoek is de spraakgestuurde echo-onderdrukker.Electrical Engineering, Mathematics and Computer ScienceTransmissie van Informati
Integraal Waterbeheer Ketelmeer: Modellering van slibtransport in het Ketelmeer
No full textIn de waterbodem van het Ketelmeer is een grote hoeveelheid sterk verontreinigd slib aanwezig. Nu de kwaliteit van het aangevoerde IJsselslib verbetert ten opzichte van de kwaliteit in de jaren 60 en 70, is er sprake van het risico dat opwerveling van oud, verontreinigd slib nog jarenlang de kwaliteit van het water in het Ketelmeer, en via transport ook in het IJsselmeer, negatief beïnvloedt. Dit kan ertoe leiden dat na verloop van tijd de verontreinigde sliblagen afgedekt worden met schoner slib. Het is echter de vraag of dit overal in het Ketelmeer gebeurt, en of geplande ingrepen in het Ketelmeer invloed hebben op de mate van afdekking. De doelstelling van de studie was de operationalisering van het slibtransportmodel STRESS-2d voor het Ketelmeer en het uitvoeren van simulaties met dit model teneinde her slibtransport in de huidige situatie te beschrijven. Tevens dienden simulaties te worden uitgevoerd die de effecten vanverschillende inrichtings-en beheersvarianten op hetslibtransport latenzien. Tot slot worden de resultaten van deze studie gebruikt in simulatieberekeningen met het model IMPAQT, dat het transport van microverontreinigingen beschrijft. De sirnulatie voor de eerste variant, waarbij de huidige situatie in stand gehouden wordt, wijst uit dat het grootste deel van het Ketelrneer gekarakteriseerd wordt door netto sedirnentatie van slib. Voor het hele Ketelrneer geldt dat de gesirnuleerde slibretentie in de orde van 60% is. Dit betekent dat er in principe sprake is van een algehele afdekking van oudere sliblagen ("bodemslib") met recenter aangevoerd slib ("IJsselslib"). Met name in het centrale deel van het Ketelrneer is er echter sprake van een sterke afwisseling tussen perioden met netto sedirnentatie en perioden met netto erosie. Dit leidt in de sirnulatie tot een relatief grote hoeveelheid bodemslib in de toplaag van het sediment. Het slib dat in de huidige situatie naar het IJsselmeer getransporteerd wordt, bestaat volgens de sirnulatie voor ongeveer 30% uit bodernslib. Het naar het IJsselmeer getransporteerde slib bestaat vrijwel geheel uit de lichtste fractie. De conclusies kunnen als volgt worden sarnengevat: - De aanleg van twee scheepvaartzeulen (variant 2) heeft alleen het effect dat de erosie door scheepvaart wordt vervangen door een sterke sedimentatie in de uitgediepte geulen. De sedimentatiesnelheid in hat westeliike deel van het Ketelmeer neemt door het afvangen van veel IJsselslib in de geulen af. De hoeveelheid bodemslib neemt alleen rond de geul iets af. Het transport van slib naar het IJsselmeer verandert nauwelijks door deze ingreep; - De verwijdering van de gehele sliblaag (variant 3) heeft uiteraard tot gevolg dat het transport van bodemslib geheel verdwijnt. Door de algehele verdieping van het Ketelmeer verandert het sedimentatiepatroon enigszins, waarbij sedimentatie meer verschuift naar het centrale deel van het Ketelmeer. De retentie van slib wordt verhoogd tot 62%; - Aanleg van een zandwinput (variant 4) leidt tot een sterke slibvang in deze put. De slibretentie in het Ketelmeer neemt daardoor toe tot ongeveer 64%. In het gebied ten westen van de put neemt daardoor de netto sedimentatie af met ongeveer 40%. Omdat ook veel IJsselslib in de put sedimenteert, wordt de afdekking van oude sliblagen belangrijk gereduceerd; - De sanering van de randen van het Ketelmeer, waar dikke pakketten verontreinigd slib liggen (variant 5) heeft nauwelijks effect op de slibbalans van het Ketelmeer. Het transport van bodemslib naar het IJsselmeer neemt met ca. 25% af. Op de ontwikkeling van de waterbodemkwaliteit in niet gesaneerde gebieden heeft de ingreep nauwelijks effect. - De aanleg van een drietal recreatie-eilanden tussen Ketelhaven en Schokkerhaven (variant 6) leidt tot een verhoogde sedimentatie rond de eilanden. Dit heeft een beperkt effect op de slibbalansvan het Ketelmeeren heeft een geringe vermindering (10%) van het transport van bodemslib naar het IJsselmeer tot gevolg. Een ander gevolg is een reductie van de afdekking van bodemslib in westelijker delen van het meer. - De sanering van enkele voor de recreatie belangrijke lokaties, rond Ketelhaven en Schokkerhaven (variant 7)is lokaal van betekenis, omdat een nabij Ketelhaven gelegen gebied omslaat van een erosie- naar een sedimentatiegebied. Verder zijn de effecten klein. - De combinatie van drie varianten, waarbij zowel scheepvaartgeulen worden uitgediept, als eilanden aangelegd en havens gesaneerd (variant 8) leidt tot een grote sedimentatie in het midden-oostelijk deel van het Ketelmeer; daar waar de ingrepen gepland zijn. Op de slibbalans blijft het effect klein. Er is door deze combinatie van maatregelen enige vermindering van het transport van bodernslib naar het IJsselmeer te verwachten (20%). De afdekking van bodemslib in het midden-westen en westen van het meer wordt gereduceerd. Een belangrijke algemene conclusie die uit deze simulaties volgt, is dat uitdieping van specifieke gebieden in het Ketelmeer, er in alle gevallen toe leidt dat de afdekking van oude sliblagen in gebieden westelijk van de uitgediepte delen belangrijk gereduceerd kan worden. Hoe dichter de uitgediepte gebieden bij de IJsselmonding liggen, hoe meer IJsselslib afgevangen wordt. Dit kan de kwaliteit van het afdekkende slib in meer westelijk gelegen gebieden negatief beïnvloeden
A modality innovation approach: How can royal schiphol group identify and select future proof forms of mobility?
No full textRoyal Schiphol Group is the overarching organisation of multiple airports, among which Amsterdam Schiphol Airport. As the world around these airports is quickly changing with aviation under pressure, and a huge amount of new potential modalities, RSG is in need of an approach to deal with new kinds of modalities. This project was executed for the Innovation Hub, part of the department of Strategy & Airport Planning withing RSG. The initial assignment was to find a way in which RSG could identify and select modalities with potential. During the project, first the context was outlined by analysing the organisation of RSG and the environment in which they are operating. After this literature concerning open innovation has been compared to the way RSG handles external innovations at the moment, as this is how RSG can strengthen their MMH position further. It appeared that currently RSG misses a structured approach to handle new modalities. RSG therefore needs a strategy and a corresponding way to assess innovative modalities. An extra exploration was done, consisting of literature, interviews, observations and internal documents, which led to design principles for the strategy and the toolkit (wat waren deze).In the end a strategy is developed in which 4 steps (identifying, identified, assessing, choosing) were included. In this strategy RSG is encouraged to connect more to the world of mobility and its future with the use of an orchestrator, positioned in-between the innovation hub and a newly acquired scouting team. Executing these steps would lead to a decision on the fifth step: engaging. In the developped strategy, RSG shifts from reacting on modalities to proactively monitoring the world of mobility by providing structure in searching. In this way they can connect to this future world of mobility and by regularly assessing modalities, Schiphol can quickly change direction if necessary. Within the strategy, an orchestrator is present to lead the strategy. The orchestrator will be responsible for setting the exact strategy within the MMH direction, as he or she knows what happens in the market and within Schiphol. He or she will be building bridges between RSG and start-ups.For the assessment, a toolkit is developed in which the factors which influence the potential of a modality at Schiphol have been incorporated as well as the proposed way of working in the strategy. This is reflected in a card deck that should be used to assess modalities, and canvases that should be used to document the session and ensure follow up of the session is assured. Herein, the goal of the toolkit is to facilitate a structured discussion concerning new modalities which can be used to substantiate decision making by RSG. This report describes the entire process gone through to come to the final design. The final design is further elaborated on, an implementation plan is proposed and lastly a discussion and recommendations of the final design are provided, to provide directions in reaching its full potential.Strategic Product Desig
Study of the effect of vertical airfoil endplates on diffusers in vehicle aerodynamics
No full textDiffusers and the floor ahead of them create the majority of the downforce a vehicle creates. Outside motorsports, the diffuser is relatively unused, although its interaction with the ground is a consistent field of study owing to the aerodynamic benefits. The diffuser flow behavior is governed by three fluid-mechanical mechanisms: ground interaction, underbody upsweep, and diffuser upsweep. In addition, four different flow regimes appear when varying ride height, the vortices of which have great importance on downforce generation. The present study focuses on the diffuser’s fluid-dynamic characteristics undertaken within an academic framework with the objective of finding and understanding a high level of performance in these elements. Once the functioning of diffusers has been analyzed and understood, a new configuration is proposed: rear vertical airfoil endplates. The aim of the paper is to study the effect in performance of vertical airfoil endplates on diffusers in vehicle aerodynamics in a simplified geometry. The candidate to this geometry is the inversed Ahmed body, a geometry that is used as a model that simulates the flow behavior of car diffusers. Three different diffuser configurations are performed, namely 0¿ diffuser, 25¿ diffuser, and in the third case vertically installed rear vertical airfoil endplates are added to the 25¿ diffuser Ahmed body to change the flow field. These analyses are carried out by using open-source CFD simulation software OpenFOAM. An inlet velocity of 20 m/s is considered, as this is a typical velocity when cornering in motorsport. It is concluded that the 25¿ diffuser configuration generated more downforce than the 0¿ diffuser, which makes sense as the aim of adding a diffuser is to increase the amount of downforce produced. In addition, and as a result of the newly proposed configuration, the 25¿ diffuser Ahmed body with the vertical airfoil endplates emerges in a substantial increase of downforce thanks to the low-pressure zone generated at the back of the bodyPostprint (published version
Transforming Airport Hubs into Future-Proof Multimodal Transport Hubs
No full textDevelopments in sustainability and digitisation outline a future of mobility, with multimodal transport becoming the new normal. Travel modalities will no longer be the focal point of mobility, but passenger experiences and the services that provide these will. In a mobility landscape where the passenger experience is key, and multi-leg trips are the norm, Multimodal Transport Hubs are essential players as they can facilitate high-quality intermodal transfers. However, this advanced application of Multimodal Transport Hubs does not yet exist in practice.By employing a scoping review, this research aims to investigate the position of airport hubs as Multimodal Transport Hubs in the future of mobility, as airport hubs physically unite several transport infrastructures but only offer transfers with high-quality services within air traffic and not – to, from and between other modalities. To become future-proof, airport hubs should transform into truly Multimodal Transport Hubs that provide transfers with high-quality services from at least ultra-long to long and medium-range modalities.However, airport hubs have features such as a complex stakeholder landscape, long development times, reliance on transport operators and uncertainty about the added value of integrating new travel modalities that make modality innovation at airport hubs a systemic design challenge. This research identified a lack of theoretical knowledge regarding harnessing and integrating alternative and new modalities at airport hubs to transform them into fully integrated Multimodal Transport Hubs. In particular, how to assess and select new and alternative modalities, how to determine the appropriate level of engagement in different stages, and how to integrate new modalities at airport hubs should be investigated in future research.Marketing and Consumer ResearchApplied Ergonomics and Desig
