Zoekresultaten

The City as Black Box: Navigating Through the Surplus of Information

Experimental analysis of radially resolved dynamic inflow effects due to pitch steps

The dynamic inflow effect denotes the unsteady aerodynamic response to fast changes in rotor loading due to a gradual adaption of the wake. This does lead to load overshoots. The objective of the paper was to increase the understanding of that effect based on pitch step experiments on a 1.8 m diameter model wind turbine, which are performed in the large open jet wind tunnel of ForWind – University of Oldenburg. The flow in the rotor plane is measured with a 2D laser Doppler anemometer, and the dynamic wake induction factor transients in axial and tangential direction are extracted. Further, integral load measurements with strain gauges and hot-wire measurements in the near and close far wake are performed. The results show a clear gradual decay of the axial induction factors after a pitch step, giving the first direct experimental evidence of dynamic inflow due to pitch steps. Two engineering models are fitted to the induction factor transients to further investigate the relevant time constants of the dynamic inflow process. The radial dependency of the axial induction time constants as well as the dependency on the pitch direction is discussed. It is confirmed that the nature of the dynamic inflow decay is better described by two rather than only one time constant. The dynamic changes in wake radius are connected to the radial dependency of the axial induction transients. In conclusion, the comparative discussion of inductions, wake deployment and loads facilitate an improved physical understanding of the dynamic inflow process for wind turbines. Furthermore, these measurements provide a new detailed validation case for dynamic inflow models and other types of simulations.

The Atmosphere in Open Public Spaces

Introduction:A space’s atmosphere is an important factor in how that space is experienced. In fact, festival visitors consider the atmosphere as the most important factor in how they experience a festival (Van Vliet 2012). Atmosphere is also what distinguishes physical shops from online web shops (Van Vliet, Moes & Schrandt 2015). Much research underlines the influence of atmosphere on cognitive and emotional processes. As early as 1956, research showed that an assessment of facial expressions in photographs depended on the atmosphere of the space in which the photos were viewed (Maslow & Mintz 1956). The importance of atmosphere inspired the search for ways to influence visitors and allowing them to react to, and even (co-)design, a space’s atmosphere – from museum spaces (Noordegraaf 2012) to urban spaces, from consciously-manipulated spaces to the now inevitable layer of digital information that has entered the public sphere (Mitchell 2005). Researchers have been studying the influence of atmosphere for decades, particularly through the lens of environmental psychology, which focuses on the interplay between humans and their environment (Mehrabian & Russell 1974; Steg, Van den Berg & De Groot 2012). A milestone in atmosphere research was the introduction of the concept of ‘atmospherics’ by Kotler (1973). From here, research into atmosphere mainly took place in the context of marketing research into consumer behaviour in shops and service environments such as restaurants, hotels, museums and festivals (Van Vliet 2014). The question here is whether these gathered insights contribute to understanding how atmosphere works in open public spaces.

Ethics in design Education, but completely different

An parametric investigation into the effect of low induction rotor (LIR) wind turbines on the levelised cost of electricity of a 1 GW offshore wind farm in a North Sea wind climate

In this report, the details of an investigation into the eect of the low induction wind turbines on the Levelised Cost of Electricity (LCoE) in a 1GW oshore wind farm is outlined. The 10 MW INNWIND.EU conventional wind turbine and its low induction variant, the 10 MW AVATAR wind turbine, are considered in a variety of 10x10 layout configurations. The Annual Energy Production (AEP) and cost of electrical infrastructure were determined using two in-house ECN software tools, namely FarmFlow and EEFarm II. Combining this information with a generalised cost model, the LCoE from these layouts were determined. The optimum LCoE for the AVATAR wind farm was determined to be 92.15 e/MWh while for the INNWIND.EU wind farm it was 93.85 e/MWh. Although the low induction wind farm oered a marginally lower LCoE, it should not be considered as definitive due to simple nature of the cost model used. The results do indicate that the AVATAR wind farms require less space to achieve this similar cost performace, with a higher optimal wind farm power density (WFPD) of 3.7 MW/km2 compared to 3 MW/km2 for the INNWIND.EU based wind farm.

Portrait of a scientist

This interview-based article about Hubert Hermans, founder of The Dialogical Self Theory (DST), was intended to determine the founder’s personal relationship to the construction and development of his theory and to provide a portrait of the engaged scientist and vulnerable researcher at work. DST lends itself to interdisciplinary research and practice, and is used in diverse fields and contexts (e.g. psychotherapy; bereavement scholarship; higher education). However, little has been written about the founder of the theory. I embarked on this project to illuminate the researcher and theorist as an individual who taps into personal material for practical and conceptual learning, and to honour Hermans’s contribution to the field of psychology, in the spirit of a Festschrift. Reinekke Lengelle (02 Apr 2021): Portrait of a scientist: in conversation with Hubert Hermans, founder of Dialogical Self Theory1, British Journal of Guidance & Counselling, DOI: 10.1080/03069885.2021.1900779