Conclusion

The current (and largely unforeseen) COVID-19 pandemic highlights the value of scenario analysis as a complementary exercise to standard, extrapolative prediction. In this chapter, we review our main findings for geopolitical scenario analysis in general, and for Antarctic geopolitical futures in particular. We conclude that the Antarctic Treaty promotes effective governance of a region described in the Madrid Protocol as ‘a natural reserve devoted to peace and science'. We hope to have shown that a classical geopolitical lens is important and relevant to the study of Antarctic futures. On the specific topic of militarisation, we identified some key driving forces for change and equilibrium. How well the ATS responds to these driving forces will turn on its resilience as a governance system. By this, we mean ‘a capacity to prepare for, to respond to, or bounce back from problems or perturbations and disturbances, which cannot necessarily be predicted or foreseen in advance' (Chandler and Coaffee 2017). As we have seen, scenarios are useful in this zone beyond standard prediction—provided they are plausible, rigorous, and robust. It is our hope that like-minded Parties and researchers might collaborate in scenario work, to contribute to the resilience of the ATS in the challenging years ahead. © 2022, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.

Experimental and numerical evaluation of a novel dual-channel windcatcher with a rotary scoop for energy-saving technology integration

With the increasing requirements for fresh air supply in buildings after the COVID-19 pandemic and the rising energy demand from buildings, there has been an increased emphasis on passive cooling techniques such as natural ventilation. While natural ventilation devices such as windcatchers can be a sustainable and low-cost solution to remove indoor pollutants and improve indoor air quality, it is not as reliable as mechanical systems. Integration with low-energy cooling, heating or heat recovery technologies is necessary for operation in unfavourable outdoor conditions. In this research, a novel dual-channel windcatcher design consisting of a rotary wind scoop and a chimney was proposed to provide a fresh air supply irrespective of the wind direction. The dual-channel design allows for passive cooling, dehumidification and heat recovery technology integration to enhance its thermal performance. In this design, the positions of the supply and return duct are "fixed” or would not change under changing wind directions. An open wind tunnel and test room were employed to experimentally evaluate the ventilation performance of the proposed windcatcher prototype. A Computational Fluid Dynamic (CFD) model was developed and validated to further evaluate the system's ventilation performance. The results confirmed that the system could supply sufficient fresh air and exhaust stale air under changing wind directions. The ventilation rate of the rotary scoop windcatcher was higher than that of a conventional 8-sided multidirectional windcatcher of the same size. © 2023 The Author(s)

PREDICTION OF THE MAXIMUM WIND SPEED IN INDOOR ENVIRONMENTS FOR EFFICIENT NATURAL VENTILATION

The efficient natural ventilation in indoor environments is extremely important especially this period with the appearance of new hazardous viruses such as COVID-19. It is well known that the maximum wind speed causes the lowest individual exposure to hazardous substances in an environment (either indoor or outdoor) and as a result its reliable prediction by a numerical model (either simple or complex) becomes of utmost importance. In this study a deterministic model, that was developed for the outdoor environment, is examined as a possible candidate to predict the maximum wind speed in indoor environments. For the needs of the study a wind tunnel experiment is simulated by the LES methodology in order to acquire the maximum wind speed at various locations in an indoor environment. Then the deterministic model, without any change in its parameters, is validated successfully with the LES maximum wind speeds. The present deterministic model can be incorporated in simple methodologies (e.g. RANS) provided that the latest are able to predict the mean speed, the turbulent intensity and a hydrodynamic time scale. © British Crown Copyright (2022)

Experimental and numerical evaluation of a novel dual-channel windcatcher with a rotary scoop for energy-saving technology integration

With the increasing requirements for fresh air supply in buildings after the COVID-19 pandemic and the rising cost of energy, there has been an increased emphasis on natural ventilation techniques. While natural ventilation devices such as windcatchers can be a low-cost solution to remove indoor pollutants and improve indoor air quality, it is not as reliable as mechanical systems. Integration with low-energy cooling, heating or heat recovery technologies is necessary for operation in unfavourable outdoor conditions. In this research, a novel dual-channel windcatcher design consisting of a rotary wind scoop and a chimney was proposed to provide a fresh air supply irrespective of the wind direction. The dual-channel design allows for passive cooling, dehumidification and heat recovery technology integration to enhance its thermal performance. In this design, the positions of the supply and return duct are "fixed” or would not change under changing wind directions. An open wind tunnel and test room were employed to experimentally evaluate the ventilation performance of the proposed windcatcher prototype. A validated Computational Fluid Dynamic (CFD) model was developed to further evaluate the system's performance. The results confirmed that the system could supply sufficient fresh air and exhaust stale air under changing wind directions. The ventilation rate of the rotary scoop windcatcher was higher than that of a conventional 8-sided multidirectional windcatcher of the same size.

Numerical Method to Generate and Evaluate Environmental Wind Over Hills: Comparison of Pedestrian Winds Over Hills and Plains

It is well known that the wind profile at altitudes below 10m from mean sea level (MSL) depends on the geometry of terrain, due to the boundary layer phenomenon. Hence, the profile of wind changes for hilly terrains and mountainous regions when compared with the plain regions. This phenomenon has become important to study due to the large-scale urbanisation taking place over hilly regions. The changing wind profile presents a challenge to evaluate the pedestrian winds, as depending on the aspect of the terrain an additional vertical velocity component is experienced due to the upwind climb of the winds. This creates a wind profile that is twisted in form. While wind tunnel studies have attempted to recreate this twisted wind profile (TWP), due to the inherent deficiency of wind tunnels to simultaneously map velocity and flow conditions, a lack of three-dimensional flow profile hinders pedestrian comfort evaluation. In the wind tunnel studies, it was also observed that small vertical eddies and wakes behind the interfering building were not identified which are an important factor to determine the pollution load dispersion. The authors have developed a numerical model to generate the twisted wind profile. The specialty of the numerical model lies in it’s unique boundary conditions that enable the visualization and quantification of the complete 3D wind profile, when the wind over a hilly terrain interacts with urban infrastructures. The developed model was validated with the wind tunnel experiments done previously by Tse and colleagues. The specialty of the model is that it ensures horizontal homogeneity while creating vertical heterogeneity. From the 3D flow profile hence generated the authors were able to deduce that the impact of twisted wind profile depends on the yaw angle of wind interacting with the structure and not on the wind attack angle. Also, the more the twist of the wind, more is the clockwise shifting of the far wakes behind the building. It was also seen that there are more low velocity zones in the pedestrian winds over a hill in comparison to that over the plains. The vertical eddies that aid in convective removal of pollutants were also missing in case of pedestrian winds over hilly terrains, which raises the risk of pollutant accumulation. The same was also observed in Hong-Kong during COVID 19, where due to the twisted nature of wind flow, the virus load increased and natural ventilation was inadequate in the removal of the viral load in the air near urban areas. © 2022, Penerbit Akademia Baru. All rights reserved.

Air Plasma Sterilizer Using a Parallel Dielectric Barrier Discharge

Air sterilizer is one of the essential components in combating the Covid-19. A wind tunnel model of the air sterilizer using a dielectric barrier discharge plasma is proposed to destroy the virus by direct contact with the plasma. Dangerous ozone production in the plasma reactor should be controlled to a safe level. Two parameters affecting the ozone concentration, i.e., electrical power and airflow, were investigated. The DBD reactor was a cell constructed from an array of alternate electrodes. The plasma was generated by an AC high voltage generator with a range of 2kV -3kV. The power and the high voltage were varied by controlling the DC input voltage of the generator. The airflow was varied by controlling the speed of an exhaust fan from 0.5 m/s to 3.0 m/s. The state was characterized using optical emission spectroscopy in the range of 200 nm – 1000 nm. The results showed that both parameters played a significant role in ozone concentration. The trend of the ozone is strongly correlated with the OH species, which reacts with oxygen. The highest ozone concentration of 4.51 ppm was observed at the DC voltage around 19 volts or the power of 34.2 watts. However, a decrease of the ozone concentration at a voltage higher than 19 volts related to 2.9 kV was observed. In general, the data showed that faster airflow decreases ozone concentration. A drastic decrease of the nitrogen species sustaining the plasma occurred at the airflow higher than 2 m/s.

Development of Hybrid Laboratory Sessions During the COVID-19 Pandemic

This paper presents the hybrid delivery method of a laboratory experiment at the Stability Wind Tunnel of Virginia Tech to some 170 students during April 2020, which can be considered the early stages of the COVID-19 induced lockdown. The steps of converting the hands-on labs to hybrid labs are presented in detail. Namely, a videoconferencing tool was used to (i) stream the instrumentation used, (ii) provide live video feed, and (iii) to interact with the students. Labs began with a remote tour of the facility, whilst the presence of an expert-at-a-distance added key value to the labs as it enhanced students conceptual understanding via verbal interaction. The experiments were then performed by laboratory personnel while student’s engagement was kept high via the teleconferencing session. At the end of the two-week laboratory campaign, the students provided feedback of the laboratory sessions via an open-ended and closed-ended survey. They highlighted the added value of expert-at-distance, the live video feed, and the ability of working with instructors. While their feedback was rather positive, students showed a strong preference toward hands-on laboratories. Overall, the methodologies presented here can be considered a relatively low-cost method to upgrade hands-on laboratories to hybrid or remote labs. © 2022, Advances in Engineering Education. All Rights Reserved.

In Situ Observations of Wind Turbines Wakes with Unmanned Aerial Vehicle BOREAL within the MOMEMTA Project

The MOMENTA project combines in situ and remote sensing observations, wind tunnel experiments, and numerical modeling to improve the knowledge of wake structure in wind farms in order to model its impact on the wind turbines and to optimize wind farm layout. In this context, we present the results of a first campaign conducted with a BOREAL unmanned aerial vehicle (UAV) designed to measure the three wind components with a horizontal resolution as fine as 3 m. The observations were performed at a wind farm where six turbines were installed. Despite the strong restrictions imposed by air traffic control authorities, we were able to document the wake area of two turbines during two flights in April 2021. The flight patterns consisted of horizontal racetracks with various orientations performed at different distances from the wind turbines;thus, horizontal wind speed fields were built in which the wind reduction area in the wake is clearly displayed. On a specific day, we observed an overspeed area between the individual wakes of two wind turbines, likely resulting from the cumulative effect of the wakes generated behind two successive rows of turbines. This study demonstrates the potential of BOREAL to document turbine wakes.

Swept Tip Blades for Mach-Scaled High Speed Tiltrotor Tests

The objective of this proposal was to design, fabricate, and characterize, highly twisted (-30 degrees to -45 degrees) and swept (20 degrees back) composite tilt rotor blades. The swept tip is the novel and new basic research component. Comprehensive analysis performed by the US Government and Academia in the last decade have shown the potential of swept tip blades in extending whirl flutter boundary. Swept tip blades can be also contribute positively to DoDs vision of 2X speed of Future Vertical Lift (FVL). The intent is to follow-up this seed program with wind-tunnel testing of the blades at Maryland Tiltrotor Rig (MTR) at the Glenn L Martin wind tunnel. The project tracked all its milestones and completed all deliverables. The blades were designed, fabricated, characterized, integrated on the MTR, and spun-up for loads check-out on Sep-Oct 2019 a few months before the campus and the facilities shut down due to covid-19.

Wind tunnel-based testing of a photoelectrochemical oxidative filter-based air purification unit in coronavirus and influenza aerosol removal and inactivation.

Recirculating air purification technologies are employed as potential means of reducing exposure to aerosol particles and airborne viruses. Toward improved testing of recirculating air purification units, we developed and applied a medium-scale single-pass wind tunnel test to examine the size-dependent collection of particles and the collection and inactivation of viable bovine coronavirus (BCoV, a betacoronavirus), porcine respiratory coronavirus (PRCV, an alphacoronavirus), and influenza A virus (IAV), by a commercial air purification unit. The tested unit, the Molekule Air Mini, incorporates a MERV 16 filter as well as a photoelectrochemical oxidating layer. It was found to have a collection efficiency above 95.8% for all tested particle diameters and flow rates, with collection efficiencies above 99% for supermicrometer particles with the minimum collection efficiency for particles smaller than 100 nm. For all three tested viruses, the physical tracer-based log reduction was near 2.0 (99% removal). Conversely, the viable virus log reductions were found to be near 4.0 for IAV, 3.0 for BCoV, and 2.5 for PRCV, suggesting additional inactivation in a virus family- and genus-specific manner. In total, this work describes a suite of test methods which can be used to rigorously evaluate the efficacy of recirculating air purification technologies.