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2023/2024, 1r quadrimestre

2023/2024, 2n quadrimestre

This article explores the potential impact of short-haul flight bans in Spain. We build the rail and flight network for the Spanish peninsula, merging openly available ADS-B-based data, for the reconstruction of air schedules and aircraft rotations, and rail operator data, for the modelling of the rail network. We then simulate a ban that would remove flights having a suitable train replacement, \ie representing a trip shorter than a threshold that we vary continuously up to 15-h. We study the impact in terms of 1) air route reduction, 2) aircraft utilisation and fleet downsizing for airlines, 3) airport infrastructure relief and rail network requirements, 4) CO2 emissions, and 5) possible itineraries and travel times for passengers. We find that a threshold of 3 hours (banning all flights with a direct rail alternative faster than three hours) presents some notable advantages in emissions while keeping the aircraft utilisation rate at an adequate level. Interestingly, the passengers would then experience an increase in their itinerary options, with only a moderate increase in their total travelling times., This work is part of the MultiModX project which is funded by the European Union’s Horizon Europe – SESAR 3 programme (Grant Agreement 101114815)., Peer Reviewed, Postprint (published version)

Resolved, 2023/2024, 2n quadrimestre

With increasing environmental concerns and the significant impact of aviation, improving efficiency and reducing the ecological footprints of flights have become urgent needs. Although studies in this field have grown, air traffic research still faces challenges due to the limited availability of comprehensive open data. The urgency to decrease emissions is evident, especially since sustainable aviation fuels (SAF) have yet to achieve widespread adoption. Efforts are focused on advancing aircraft performance and implementing efficient practices such as continuous descent operations (CDO). The mandatory implementation of ADS-B technology has notably improved safety and air traffic management by providing real-time aircraft information. OpenSky, which consists of a network of sensors from volunteers around the world, plays a crucial role by offering free access to air traffic data collected using ADS-B, thereby creating a large database to improve airspace efficiency and safety. Additionally, tools like OpenAP, a model for obtaining aircraft performance and emissions, can use this open data to conduct detailed studies on fuel consumption, emissions, and optimization of flight trajectories. Aviation operations entail substantial costs, including operational and en-route service fees managed by EUROCONTROL, which significantly influence cost optimization strategies. This project utilizes OpenSky and OpenAP to analyze real flight data, assessing economic, environmental, and efficiency impacts across specific European routes and airports. Aviation operations entail substantial costs, including operational and en-route service fees managed by EUROCONTROL, which significantly influence cost optimization strategies. One of the objectives of this project is to investigate the relationship between fuel consumption and en-route charges, aiming to identify cost-effective strategies, factors influencing fuel consumption, and the balance between costs and emissions to determine if, Objectius de Desenvolupament Sostenible::9 - Indústria, Innovació i Infraestructura, Objectius de Desenvolupament Sostenible::13 - Acció per al Clima

2023/2024, 2n quadrimestre

Fuel consumption is a crucial consideration in the aviation industry. This last one, integral to global connectivity, faces significant environmental concerns due to the escalating demand for air travel and its substantial contribution to greenhouse gas emissions. In this thesis, we present predictive models calculating gate-to-gate fuel consumption, using simple variables such as flight distance, and taking into account the available number seats for each aircraft, in contrast with other flight consumption calculators. The main goal of this work is to construct an indicator that can be used to compare emissions with other travel alternatives. Specifically, we develop the theoretical framework for the presented models and showcase their results. Using the model with best accuracy, a LightGBM model, we demonstrate a real-world application by conducting a CO2 emission comparison between flight and rail routes.

Regional and local thermally driven winds are planetary boundary layer phenomena frequently observed on Mars over sloping and flat regions, when diurnal surface temperature variations are significant and large-scale winds are sufficiently weak. In particular, slope flows are prevalent in many areas on Mars, where they can reach high speeds and have a substantial impact on the near-surface wind patterns, pressure diurnal cycle, aeolian activity, etc. This work first reviews literature on Martian winds, listing wind speeds obtained either numerically or from in situ measurements, with special emphasis on slope flows. Second, a methodology is presented to perform numerical simulations of slope flows on Mars using the open-source computational fluid dynamics code OpenFOAM. Slope winds are then studied in a simplified Martian mountain-valley configuration, using realistic values for various parameters, such as the slope angle and temperature variation. The incompressible Navier-Stokes equations with Boussinesq approximation are used, along with the Reynolds-averaged Navier-Stokes turbulence model. Radiant heat transfer is included and proven to be paramount for a correct description of Martian slope winds. Results of velocity and temperature profiles are obtained for various slope angles. These simulations aim to provide further insight on the behavior of slope winds on Mars, to simplify the process of assessing numerous potential landing sites for upcoming missions, since these highly regular winds could be useful, for instance, for dust removal applications., This research was funded by AGAUR, with Grant 2021 SGR 01049, and by the Spanish Science and Innovation Ministry (MCIN) within the project TABL4CW, funded by MCIN/AEI/10.13039/50110001133, with Grant PID2019‐105162RB‐I00., Peer Reviewed, Objectius de Desenvolupament Sostenible::7 - Energia Assequible i No Contaminant, Postprint (published version)

An OpenFOAM computational fluid dynamics model setup is proposed for simulating thermally driven winds in mountain–valley systems. As a first step, the choice of Reynolds Averaged Navier–Stokes k-e turbulence model is validated on a 3D geometry by comparing its results vs. large-eddy simulations reported in the literature. Then, a numerical model of an idealised 2D mountain–valley system with mountain slope angle of 20° is developed to simulate thermally driven winds. A couple of top surface boundary conditions (BC) and various combinations of temperature initial conditions (IC) are tested. A transient solver for buoyant, turbulent flow of incompressible fluids is used. Contrary to classical approaches where buoyancy is set as a variable of the problem, here temperature linearly dependent with altitude is imposed as BC on the slope and successfully leads to thermally driven wind generation. The minimum fluid domain height needed to properly simulate the thermally driven winds and the effects of the different setups on the results are discussed. Slip wall BC on the top surface of the fluid domain and uniform temperature IC are found to be the most adequate choices. Finally, valleys with different widths are simulated to see how the mountain–valley geometry affects the flow behaviour, both for anabatic (daytime, up-slope) and katabatic (nighttime, down-slope) winds. The simulations correctly reproduce the acceleration and deceleration of the flow along the slope. Increasing the valley width does not significantly affect the magnitude of the thermally driven wind but does produce a displacement of the generated convective cell., This research was funded by AGAUR/Generalitat de Catalunya, with grant number 2017 SGR 1278, and by the Spanish Science and Innovation Ministry (MCIN) within the project TABL4CW, with grant number PID2019-105162RB-I00, funded by MCIN/AEI/10.13039/501100011033., Objectius de Desenvolupament Sostenible::7 - Energia Assequible i No Contaminant, Objectius de Desenvolupament Sostenible::7 - Energia Assequible i No Contaminant::7.2 - Per a 2030, augmentar substancialment el percentatge d’energia renovable en el con­junt de fonts d’energia, Postprint (published version)

Resolved, 2022/2023, 1r quadrimestre

2022/2023

The main aim of this project is to analyze the capacity and demand of the passenger terminal of an airport. In the future, a considerable growth in the flow of passengers is expected, since the base of operations of an airline will be installed. In order to realize the demand study, a current and horizon year flight plan are used. Once the demand is known, the capacity is calculated through a static analysis, which means that the different subsystems of the airport are sized. This capacity study is carried out using the 10th edition of the IATA Airport Development Reference Manual (ADRM). When the capacity of the different areas is obtained, the results obtained are compared with the dimensions and equipment of the existing terminal. Therefore, it is known if the existing facilities are optimal for the current and future situation. In the case of security control, an expansion of the equipment would be needed to provide an optimal level of service. In addition, a dynamic analysis is performed through AirTOP simulation software. The terminal is modelled, specifically, the Check-In, Bag Drop and security control areas. Next, the terminal is simulated with future demand and the level of service (waiting time and space per passenger in waiting areas) is evaluated. Finally, based on the level of service obtained in the simulation, different improvements are proposed in order to optimize the dimensions and equipment of the terminal.

During the flight, the crew might consider modifying their planned trajectory, taking into account currently available information, such as an updated weather forecast report or the already accrued amount of delay. This modified planned trajectory translates into changes on expected fuel and flying time, which will impact the airline’s relevant performance indicators leading to a complex multiple-criteria decision-making problem. Pilot3, a project from the Clean Sky Joint Undertaking 2 under European Union’s Horizon 2020 research and innovation programme, aims to develop an objective optimisation engine to assist the crew on this process. This article presents a domain-driven approach for the selection of the most suitable multiple-criteria decision-making methods to be used for this optimisation framework. The most relevant performance indicators, based on airline’s objectives and policies, are identified as: meeting on-time performance, leading to a binary value in a deterministic scenario; and total cost, which can be disaggregated into sub-cost components. The optimisation process consists of two phases: first, Pareto optimal solutions are generated with a multi-objective optimisation method (lexicographic ordering); second, alternative trajectories are filtered and ranked using a combination of multi-criteria decision analysis methods (analytic hierarchy process and VIKOR). A realistic example of use shows the applicability of the process and studies the sensibility of the optimisation framework., This work has been performed as part of Pilot3 project which has received funding from the Clean Sky 2 Joint Undertaking (JU) under grant agreement No 863802. The JU receives support from the European Union’s Horizon 2020 research and innovation programme and the Clean Sky 2 JU members other than the Union. The opinions ex- pressed herein reflect the authors’ views only. Under no circumstances shall the Clean Sky 2 Joint Undertaking be responsible for any use that may be made of the information contained herein., Peer Reviewed, Objectius de Desenvolupament Sostenible::9 - Indústria, Innovació i Infraestructura, Postprint (published version)

The study of Martian winds holds significant scientific interest and potential practical applications. For instance, understanding the dynamics and behaviour of Martian winds is crucial in order to properly evaluate and select landing sites for missions to Mars [1]. The study of wind patterns is also critical in determining the capacity of Martian winds to remove dust from solar panels, thereby improving their performance and longevity [2]. Furthermore, Martian winds' effects on dust are fundamental to comprehending the planet's weather and climate [3], and finally, studying regional-scale sand transport and dune formation can contribute to gain a deeper understanding of Martian geological processes [4]. Therefore, the investigation of Martian winds represents a multidisciplinary approach with meaningful repercussions for planetary science and space exploration. This work focuses on analysing the formation of thermally-driven winds, which are typically observed in inclined regions, examining their implications for the production of renewable wind energy. While wind energy may not be ideal for initial stages of human settlement on Mars, due mainly to the low density of the Martian atmosphere, it has the potential to serve as a renewable energy source in the long term and as a backup for solar energy [5]. Thermally-driven winds can attain considerably high velocities for steep slopes (values of up to 17 m/s [6]), exerting a dominant influence on the near-surface wind. The study of maximum velocities (Fig. 1) and the heights at which these velocities typically occur could be of particular interest for determining the optimal placement of wind energy resources (such as wind turbines) for future energy production on planet Mars. Within the scope of this study, 2D simulations of slope winds on Mars are achieved using the open source computational fluid dynamics (CFD) code OpenFOAM. Several slope angles (ranging from 5º up to 20º) are considered. Following [7], the incompr, Peer Reviewed, Objectius de Desenvolupament Sostenible::13 - Acció per al Clima, Objectius de Desenvolupament Sostenible::7 - Energia Assequible i No Contaminant, Postprint (published version)

Resolved, 2023/2024, 1r quadrimestre

No corregit: per practicar, correcció disponible en un altre fitxer, 2022/2023, 2n quadrimestre

Given the projected growth in future demand for the airport under study, this project aims to evaluate the capacity of the movement area (runway, taxiways, and apron). To achieve this objective, a static analysis is conducted based on the standards of the Federal Aviation Administration (FAA), along with a dynamic analysis using the fast-time simulation software, AirTOP. A study of the current and future design day flight schedule is carried out, identifying peak hours for departures and arrivals at the airport, as well as the number of aircraft simultaneously occupying parking stand at the airport. Additionally, the capacity of the subsystems of the movement area is statically calculated, establishing the airport's capacity based on the lowest value among the subsystem capacities. The obtained capacity is then compared with the demand on the Horizon Year design day (future situation), which is expected to increase based on historical airport statistics and the establishment of a new airline's operational base at the airport. After the capacity - demand study, it is concluded that the apron capacity needs to be increased to accommodate future demand. A sizing proposal (expansion of the apron) is developed, and a static analysis is conducted similarly to the initial situation. In this case, a dynamic analysis is also performed using AirTOP. The scenario under study is modelled, the simulation is run, and the model is validated/calibrated to evaluate the airport's capacity in the future. The dynamic analysis considers time and the interaction among subsystems, thus allowing for the evaluation of delays, performance indicators, and the detection of possible operational inefficiencies or bottlenecks. Finally, the two analyses are compared to highlight the advantages of the dynamic analysis over the static and to draw conclusions regarding the capacity of the airport's movement area in the future., Objectius de Desenvolupament Sostenible::9 - Indústria, Innovació i Infraestructura

Resolved, 2022/2023, 2n quadrimestre

The network is a key asset for airlines because it defines their market power and constrains resource 12 allocation. In a hub and spoke network, short flights feed the airlines’ hubs to distribute passengers. 13 This network configuration is widely used by the industry as it increases their potential global con- 14 nectivity. Therefore, the analysis of the hub connectivity is paramount when assessing the efficiency 15 of long-haul airline’s schedules., This work is part of thee MultiModX project which is funded by the European Union’s Horizon Europe – SESAR 3 programme (Grant Agreement 101114815)., Peer Reviewed, Objectius de Desenvolupament Sostenible::11 - Ciutats i Comunitats Sostenibles, Objectius de Desenvolupament Sostenible::11 - Ciutats i Comunitats Sostenibles::11.2 - Per a 2030, proporcionar accés a sistemes de transport segurs, assequibles, accessi­bles i sostenibles per a totes les persones, i millorar la seguretat viària, en particular mitjan­çant l’ampliació del transport públic, amb especial atenció a les necessitats de les persones en situació vulnerable, dones, nenes, nens, persones amb discapacitat i persones grans, Postprint (published version)

The deliverable provides the outcomes from the verification and validation activities carried during the course of work package 5 of the Pilot3 project, and according to the verification and validation plan defined in deliverable D5.1 (Pilot3 Consortium, 2020c). Firstly, it presents the main results of the verification activities performed during the development and testing of the different software versions. Then, this deliverable reports on the results of internal and external validation activities, which aimed to demonstrate the operational benefit of the Pilot3 tool, assessing the research questions and hypothesis that were defined at the beginning of the project. The Agile principle adopted in the project accompanying with the five five-level hierarchy approach on the definition of scenarios and case studies enabled the flexibility and tractability in the selection of experiments through different versions of prototype development. As a result of this iterative development of the tool, some of the research questions initially defined have been revisited to better reflect the validation results. The deliverable also reports the feedback received from the experts during the internal and external meetings, workshops and dedicated (on-line) site visits. During the validation campaign, both subjective qualitative information and objective quantitative data were collected and analysed to assess the Pilot3 tool. The document also summarises the results of the survey that were distributed to the external experts to assess the human-machine interface (HMI) mock-up developed in the project., This deliverable is part of a project that has received funding from the Clean Sky Joint Undertaking under grant agreement No 863802 under European Union’s Horizon 2020 research and innovation programme., Peer Reviewed, Postprint (published version)

Planetary boundary layer phenomena, such as slope winds and nocturnal low-level jets, are frequent on Mars, e.g., whenever diurnal surface temperature variations are significant, and large-scale winds are weak. In particular, thermally-driven winds are very common over sloping regions; they can reach significantly high speeds for steep slopes, and govern near-surface winds in many sites. Simulations of this type of flows on Earth have usually been conducted using commercial computational fluid dynamics software (CFD). In this work, a set-up is described for numerically simulating slope flows on Mars within the framework of the open-source code OpenFOAM CFD. For this purpose, thermally-driven winds are analysed in an idealised 2D Martian mountain-valley system with realistic values of parameters such as the slope angle, temperature difference between the atmosphere and slope, etc. The fluid domain dimensions, and the temperature and pressure initial and boundary conditions used in this work were tested and proven suitable in previous similar investigations for Earth applications. Large-eddy simulations (LES) turbulent model is used here. The results obtained for velocity and temperature profiles are shown both for anabatic (up-slope) and katabatic (down-slope) winds. This study shows the potential of the proposed methodology and the performance of OpenFOAM. Future work aims at facilitating the screening of large numbers of candidate landing sites for future Mars missions, and at estimating the thermally-driven wind speeds for wind resource assessment., This work has been supported by the project PID2019-105162RB-I00 funded by MCIN/AEI/10.13039/501100011033 and by the project 2017 SGR 1278 from the AGAUR from Generalitat de Catalunya, Peer Reviewed, Objectius de Desenvolupament Sostenible::7 - Energia Assequible i No Contaminant::7.2 - Per a 2030, augmentar substancialment el percentatge d’energia renovable en el con­junt de fonts d’energia, Objectius de Desenvolupament Sostenible::7 - Energia Assequible i No Contaminant, Objectius de Desenvolupament Sostenible::7 - Energia Assequible i No Contaminant::7.1 - Per a 2030, garantir l’accés universal a serveis d’energia assequibles, confiables i moderns, Postprint (published version)

Commercial computational fluid dynamics (CFD) codes have often been used for simulation of atmospheric boundary layer (ABL) flows. The present work explores the potential of the open-source CFD software OpenFOAM for simulating thermally-driven winds, by comparing several turbulence models. Indeed, in ABL and other large-scale flows, turbulence is critical to the mixing process of momentum and buoyancy, and simulations with commercial CFD codes have usually been done with Reynolds-Averaged Navier-Stokes (RANS) turbulence modelling. In this work, the formation of thermally-driven winds is studied in an idealised mountain-valley system, with realistic values of parameters such as the slope angle, the diurnal temperature cycle, etc. Performances of various OpenFOAM RANS turbulence models (k–e, re-normalisation group (RNG) k–e, k–¿ shear stress transport (SST)) are compared. A preliminary study of LES using Smagorinsky closure is also contemplated. Velocity contours, velocity and temperature profiles, the shapes of vortexes/convective cells, and the computational times are presented for all the studied turbulence models, to help identify the most suitable one for simulation of thermally-driven winds., This work is supported by the project PID2019-105162RB-I00 funded by MCIN/AEI/10.13039/501100011033 and by the project 2017 SGR 1278 from the AGAUR Generalitat de Catalunya., Peer Reviewed, Objectius de Desenvolupament Sostenible::7 - Energia Assequible i No Contaminant::7.1 - Per a 2030, garantir l’accés universal a serveis d’energia assequibles, confiables i moderns, Objectius de Desenvolupament Sostenible::7 - Energia Assequible i No Contaminant, Objectius de Desenvolupament Sostenible::7 - Energia Assequible i No Contaminant::7.2 - Per a 2030, augmentar substancialment el percentatge d’energia renovable en el con­junt de fonts d’energia, Postprint (published version)

Resolved, 2022/2023, 1r quadrimestre

Aerodynamic design of a Formula Student racing car using Solidworks Flow Simulation. The devices designed are compatible with the Vilanova Formula Team 2022 racing car. The project also contains the development of a deep learning tool to test the track efficiency of the car. This tool compares different aerodynamic configurations in a determined track before building the car.

Permutation 1, Resolved

Permutation 1, Resolved

Resolved, 2021/2022, 2n quadrimestre

Due to the importance of developing strategies and technologies that reduce greenhouse gas emissions, this study has the objective of finding models that explain the evolution of CO2 (carbon dioxide) emissions as a function of flight level and the mass on board of an aircraft. The flights that will be studied are those of short and medium distance and a medium-range narrow-body twin-engine aircraft will be used. Models have been generated thanks to Eurocontrol's IMPACT platform, which allows the simulation of complete aircraft trajectories by calculating their thrust and fuel flow throughout the flight thanks to the Base of Aircraft Data (BADA). Under the same atmospheric conditions, it will be studied, on the one hand, how the distance of a flight influences CO2 emissions per km; and, on the other hand, the influence on CO2 emissions of the cruise altitude of a flight as a function of the distance traveled, considering the influence of mass; so, the optimal altitude of flights will be search based on the distance flown. In addition, a comparison of the CO2 emissions of a 900 km round trip flight will be made to see how they increase if the aircraft brings the necessary fuel for both legs. This value will be compared with the time it takes to fill the tanks of fuel with the necessary fuel to see if it is worth refueling before each flight. Finally, two aircraft models that cover the same air transport sector will be compared to study what factors make one aircraft more efficient than another taking into account the importance of minimizing emissions per passenger wherever it is possible., Objectius de Desenvolupament Sostenible::7 - Energia Assequible i No Contaminant

The main objective of this project is to create models and study the real flight distance, horizontal and vertical flight efficiency, fuel consumption, and emissions, for short and medium-haul flights in Europe, based on real flight data obtained from ADS-B readings, using the online application Flightradar24. With most studies on consumption and emissions relying on the great circle distance (GCD) to measure the flight distance in air operations, the need to better adjust the flight time and flight distance to reality arose. To do so, all the input data on which this project is based on corresponds to real commercial flights that took place in Europe, between October 2021 and May 2022. After collecting and processing the data using software tools such as Matlab and Excel, a model was created to better understand which factors affect the flight distance. These models can be useful to, for example, study the possibility of intermodality, a solution that proposes that some flights are replaced by more sustainable transport models, such as the train. Then, the real flight distance and maximum flight level are compared to the GCD and the reference altitude respectively, to find the Horizontal Flight Efficiency (HFE) and Vertical Flight Efficiency (VFE). Finally, a fuel consumption, and consequently, an emission study, is carried out not to only find out the relationship between emissions and flight efficiency, but also to assess how different air traffic management (ATM) solutions, such as free route airspace or continuous descent operations affect the consumption and emissions. The results obtained allow the user to, knowing the GCD between two airport pairs, find an estimation of the real flight distance and greenhouse gas emissions. Additionally, after assessing the current situation in European airspace regarding flight efficiency, it is studied if the defined ATM solutions indeed reduce, and how much, the fuel burnt and emissions., Objectius de Desenvolupament Sostenible::13 - Acció per al Clima

Objectius de Desenvolupament Sostenible::13 - Acció per al Clima

Flights negatively impact the environment and the aviation industry faces significant challenges to decarbonise. This is particularly relevant for short- and medium-haul flights, as operations in these ranges can be less fuel efficient per passenger transported and other transport alternatives could be considered, e.g. rail. The quantification of this environmental impact is usually reliant on estimations of CO2 emissions. Currently available models tend to focus on simple linear relationships between distance and/or time and emissions, which do not differentiate by operation type, or tend to be based on fuel consumption models, which require detailed flight and aircraft parameters on a flight by flight basis, limiting the possibility of network level analysis. We present analytical models calculating gate-to-gate CO2 emissions and travel time based on flight distance and on the number of available seats. These models enable the comparison of the environmental impact of aviation with other means of transport, as operations are translated into passenger transported and time required. Emissions estimated by these models are in line with other CO2 calculators. The models present the advantage of being sensitive to the number of available seats, a parameter generally not explicitly considered. Their applicability is shown in practical examples: analysis of emissions and time of routes, which could potentially be complemented by high-speed rail and night trains., Objectius de Desenvolupament Sostenible::9 - Indústria, Innovació i Infraestructura, Objectius de Desenvolupament Sostenible::12 - Producció i Consum Responsables, Objectius de Desenvolupament Sostenible::13 - Acció per al Clima, Objectius de Desenvolupament Sostenible::13 - Acció per al Clima::13.2 - Incorporar mesures relatives al canvi climàtic en les polítiques, les estratègies i els plans nacionals, Postprint (published version)

Recently, there has been much interest in measuring the environmental impact of short-to-medium-haul flights. Emissions of CO2 are usually measured to consider the environmental footprint, and CO2 calculators are available using different types of approximations. We propose analytical models calculating gate-to-gate CO2 emissions and travel time based on the flight distance and on the number of available seats. The accuracy of the numerical results were in line with other CO2 calculators, and when applying an analytical fitting, the error of interpolation was low. The models presented the advantage with respect to other calculators of being sensitive to the number of available seats, a parameter generally not explicitly considered. Its applicability was shown in two practical examples where emissions and travel time per kilometre were calculated for several European routes in a simple and efficient manner. The model enabled the identification of routes where rail would be a viable alternative both from the emissions and total travel time perspectives., Objectius de Desenvolupament Sostenible::9 - Indústria, Innovació i Infraestructura::9.4 - Per a 2030, modernitzar les infraestructures i reconvertir les indústries perquè siguin sostenibles, usant els recursos amb més eficàcia i promovent l’adopció de tecnologies i processos industrials nets i racionals ambiental­ment, i aconseguint que tots els països adoptin mesures d’acord amb les capacitats respectives, Objectius de Desenvolupament Sostenible::11 - Ciutats i Comunitats Sostenibles, Objectius de Desenvolupament Sostenible::9 - Indústria, Innovació i Infraestructura, Objectius de Desenvolupament Sostenible::17 - Aliança per a Aconseguir els Objetius::17.14 - Millorar la coherència de polítiques per al desenvolupament sostenible, Objectius de Desenvolupament Sostenible::11 - Ciutats i Comunitats Sostenibles::11.2 - Per a 2030, proporcionar accés a sistemes de transport segurs, assequibles, accessi­bles i sostenibles per a totes les persones, i millorar la seguretat viària, en particular mitjan­çant l’ampliació del transport públic, amb especial atenció a les necessitats de les persones en situació vulnerable, dones, nenes, nens, persones amb discapacitat i persones grans, Objectius de Desenvolupament Sostenible::12 - Producció i Consum Responsables, Objectius de Desenvolupament Sostenible::12 - Producció i Consum Responsables::12.b - Elaborar i aplicar instruments que permetin vigilar els efectes en el desenvolupament sostenible a fi d’acon­seguir un turisme sostenible que creï llocs de treball i promogui la cultura i els productes locals, Objectius de Desenvolupament Sostenible::13 - Acció per al Clima, Objectius de Desenvolupament Sostenible::13 - Acció per al Clima::13.2 - Incorporar mesures relatives al canvi climàtic en les polítiques, les estratègies i els plans nacionals, Objectius de Desenvolupament Sostenible::17 - Aliança per a Aconseguir els Objetius, Postprint (published version)

Thermal winds appear in mountainous areas and valleys due to temperature gradients caused by the buoyancy effects associated with the diurnal heating-cooling cycle of the lower atmosphere. These winds develop over complex topographies of multiple scales, and reverse their direction twice a day, driven by formation and dissipation of temperature inversions. Winds may flow up-slope (anabatic winds), up-valley, or from the plain to the mountain massif during day-time. Conversely, during night-time, winds may flow down-slope (katabatic winds), down-valley, or from the mountain massif to the plain. Previous investigations have shown that such winds can reach relatively high speeds [1], which can be interesting for wind energy applications. Moreover, thermal winds showing higher regularity and periodicity than synoptic winds [1], can thus be more predictable, which is of special interest to the current energy market, aiming to match the energy demand with the renewable energy production, given the fact that wind energy and solar energy production cannot be controlled at will. In this work, thermal wind generation is analysed using OpenFOAM, which is an open source computational fluid dynamics software. For this analysis, an idealized numerical model of a mountain-valley system with a mountain slope angle of 20º is used. Anabatic and katabatic winds are generated imposing altitude-dependent temperature boundary conditions on the slope. OpenFOAM’s solver buoyantBoussinesqPimpleFoam is used, and validation of different turbulence models and initial conditions is done by comparing OpenFOAM simulations with results from the literature. The effects of the fluid domain height and of the valley width on the flow behaviour are also discussed. Conclusion on anabatic and katabatic wind formation and on their possible application to wind energy generation is finally drawn., Peer Reviewed, Objectius de Desenvolupament Sostenible::7 - Energia Assequible i No Contaminant, Objectius de Desenvolupament Sostenible::7 - Energia Assequible i No Contaminant::7.2 - Per a 2030, augmentar substancialment el percentatge d’energia renovable en el con­junt de fonts d’energia, Objectius de Desenvolupament Sostenible::7 - Energia Assequible i No Contaminant::7.a - Per a 2030, augmentar la cooperació internacional per tal de facilitar l’accés a la investigació i a les tecnolo­gies energètiques no contaminants, incloses les fonts d’energia renovables, l’eficiència energètica i les tecnologies de combustibles fòssils avançades i menys contaminants, i promoure la inversió en infraestructures energètiques i tecnologies d’energia no contaminant, Postprint (author's final draft)

Current route planners help people to organize their journeys by themselves. However, the most common websites offering such a service lack in integrating several features that may be useful for the user to make his/her decision, such as connection time to the airport/station, environmental criteria, etc. Moreover, the user has to spend his precious time selecting the best among the available options. The focus of this project is to provide a door-to-door solution, which may require multiple modes of transportation. Especially in cases where more than one possible route is available. Therefore, the goal is to provide the user with the best solution in terms of the user¿s preferences regarding the characteristics of the different routes. For this purpose, a multi-criteria decision-making (MCDM) algorithm was selected and implemented that satisfied a set of requirements of route planning. Three principal transport modes were studied for emissions models. Routes¿ information for cost and time are obtained from exterior online services or derived from our models. A website is built to let users select the origin and the destination in addition to expressing his/her preferences over cost, emissions and time. Also, to show the optimal route for him/her. The main objectives to fulfill are 1) Elaborate models for the calculation of the emissions for each transport mode and obtain information about the travel time and cost 2) Select and implement an MCDM algorithm 3) Design a user-friendly website for the interaction with the user and integrate the first two objectives. At the end of the project, we successfully created emissions models for three transport modes and implemented processes to obtain time and cost of a route. Our algorithm was selected as it best suited the needs of a route planner. And, a simple user-friendly website was built to provide route planning services considering user¿s preferences that implements an architecture using own models, algorithm and free, Objectius de Desenvolupament Sostenible::13 - Acció per al Clima

Peer Reviewed, Objectius de Desenvolupament Sostenible::7 - Energia Assequible i No Contaminant, Postprint (published version)

In this project, the methodology used to develop a software capable of predicting the optimal means of transport for a door-to-door route is exposed. The criteria used to compare the different means of transport are: the price of the trip, the total time of the route, the feeling of comfort that each transport system transmits and the ecological footprint that the trip causes. When choosing the best alternative, the software takes into account the weights that are assigned to each criterion, and in turn, these weights can be distributed according to the user's preferences. In this way, the optimal solution changes according to the importance that each criterion may have for one type of user or another. Once operational, the software is used to find out the best means of transportation for specific routes. It is also employed to understand what effect a scenario where only the cost and price of the trip has on the solutions, compared to a scenario in which environmental criteria are introduced. Finally, the operation of the software is also exploited to discover how the best transportation solutions vary according to users with different profiles., Objectius de Desenvolupament Sostenible::11 - Ciutats i Comunitats Sostenibles

In this work, we study the transition from squeezing to dripping during the formation of bubbles in a capillary T-junction in conditions relevant to microgravity. The junction is formed by two perpendicular cylinders of equal section (1 mm of internal diameter). The capillary number Ca (based on the continuous phase) is used as the key parameter of the study. For the range of Ca covered in this paper, the same two common bubble formation mechanisms as the ones described in the related literature have been observed: squeezing regime at low Ca and dripping regime for higher Ca. This paper provides a new value of the critical Ca for the transition from squeezing to dripping. This value has been obtained with two independent approaches, experimentally and numerically. Experimental photographs have been used to determine the value of Ca at which a gap appears between the forming bubble and the capillary’s wall, as an evidence of the activation of the shearing mechanism related to the dripping regime. Additionally, the dependence of the bubble volume on the capillary number and the gas/liquid flow rate ratio has been analysed. In this work, we also propose a new numerical approach, complementary to the experimental one, carried out with the Computational Fluid Dynamics solver ANSYS Fluent v15.0.7. Numerical simulations have been performed to study the geometry and the behaviour of the gas-liquid interface during the cycle of bubble formation. Upstream the T-junction, as the fluctuation in pressure decreases, the vertical movement of the rear meniscus (gas-liquid interface in contact with the solid vertical capillary) also decreases, and the shear stresses begins to play an active role until overcoming the squeezing mechanism. Numerical simulations presented in this paper support the experimental observations, confirming that Computational Fluid Dynamics studies can be a useful tool to improve the experimental knowledge., Peer Reviewed, Postprint (author's final draft)

This paper studies trade-offs between efficiency (performance) and fairness (equity), when assigning ATFM delay pre-tactically (on-ground at origin airport) due to reduced airport capacity at destination. Delay is assigned as the result of the optimisation of a deterministic multi-objective problem considering flight and passenger perspectives when defining objectives of performance and fairness. Two optimisation cases are presented: one where objectives are based on flight metrics, and another one where they are based on passenger metrics. The paper defines and analyses efficiency-fairness trade-offs: the concepts of price of fairness for flights and passengers are defined as the percentage of efficiency loss due to the consideration in the optimisation of fairness; whereas the price of efficiency is considered as the fairness loss relative to the maximum value of the fairness metric, when considering flight or passenger delay in the optimisation. The optimisation model is based on the ground holding problem and uses various objective functions. For performance, total delay for flights (considering reactionary delay), and total delay for passengers (considering outbound connections) are defined. For fairness, the deviation of flight arrivals from a Ration By Schedule solution, and the deviation of delay experienced by passengers with respect to the one obtained in an RBS situation are used. An illustrative application on traffic at Paris Charles de Gaulle airport, a busy European hub airport, and including realistic values of traffic is modelled. A comprehensive trade-off analysis is presented. Results show, how in some cases, gains on one stakeholder can be achieved without implying any detriment on the other one. Passengers are more sensitive to the optimisation and hence, their consideration when assigning delay is recommended. Further research should explore how to combine flight and passenger indicators in the optimisation and consider how the lack of data ava, Peer Reviewed, Postprint (author's final draft)

This deliverable starts with the proposal of Pilot3 but incorporates the development produced during the first four months of the project: activities on different workpackages, interaction with Topic Manager and Project Officer, and input received during the first Advisory Board meeting. This deliverable presents the definition of Pilot3 concept and methodology. It includes the high level the requirements of the prototype, preliminary data requirements, preliminary indicators that will be considered and a preliminary definition of case studies. The deliverable aims at defining the view of the consortium on the project at these early stages, while highlighting the feedback obtained from the Advisory Board and the further activities required to define some of the aspects of the project., This deliverable starts with the proposal of Pilot3 but incorporates the development produced during the first four months of the project: activities on different workpackages, interaction with Topic Manager and Project Officer, and input received during the first Advisory Board meeting. This deliverable presents the definition of Pilot3 concept and methodology. It includes the high level the requirements of the prototype, preliminary data requirements, preliminary indicators that will be considered and a preliminary definition of case studies. The deliverable aims at defining the view of the consortium on the project at these early stages, while highlighting the feedback obtained from the Advisory Board and the further activities required to define some of the aspects of the project., Postprint (published version)

This paper proposes a collaborative air traffic flow management (ATFM) framework, in the scope of trajectory based operations, aiming to improve the cost-efficiency for airspace users (AUs) when facing ATFM regulations. The framework consists of four modules. The first one involves the AUs initially scheduling their preferred trajectories for all their flights. Based on this initial demand, the second module (assumed to be on the Network Manager -NM- side) detects time-varying hotspots (i.e. overloaded sectors along the day). In the third module, hotspot information is shared back to the AUs who plan alternative trajectory options to avoid crossing these congested airspace volumes (in the lateral and vertical domain); as well as providing to the NM different pre-tactical delay management preferences (including ground holding, linear holding, air holding and pre-tactical delay recovery); based on their internal cost breakdown structures. Incorporating all these potential combined options, the last module computes the best trajectory selections and the optimal distribution of delay assignments, such that the cost deviation from the initial status (all the user-preferred trajectories) is minimized. This model is formulated as mixed integer linear programming (MILP) and validated by a real-world case study focused on 24 h of traffic over the French airspace. Results using the proposed framework suggest a significant system delay reduction by nearly 97% over the existing method, whilst yielding an average of less than 100 kg extra fuel consumption and 50 Euro extra route charges for the 11% flights diverted to their alternative trajectories., Peer Reviewed, Postprint (author's final draft)

In the following work an aerodynamic study is explained, which consists in seeing the influence of the earth’s surface on the wind propagation. Specifically in plains, uphill and downhill slopes, basic geometries that represent terrestrial and mountainous areas. Once the wind passes through the mentioned domains, the resulting velocity profile is analysed. All in order to provide scientific evidence to the investigations of wind energy, showing the heights where a wind turbine takes advantage of the maximum kinetic energy of the wind. To make it possible, a free and commercial program in Computational Fluid Dynamics (CFD) called OpenFOAM is used. In it, the physical conditions of the boundaries of each geometry are specified. Like the inlet of the flow, the land through which it spreads, its outlet and the top limitation. The boundary conditions are examined and the most suitable ones for this work are concluded. The roughness is simulated by the ”wall functions”, which represent the obstacle of the terrain. The turbulence that appears in consequence, is analysed by the RANS model, specifically that of k-epsilon. And in order to reduce factors that may increase this turbulence, the inlet velocity that is imposed is reduced. Physical knowledge about the Atmospheric Boundary Layer is taken into account in the work. In addition to having as reference the studies carried out by Richard and Hoxey in 1993, which modelled a theoretical velocity profile adapted to the conditions of the Atmospheric Boundary Layer. Model that is used as the theoretical velocity of each simulation, so the results will be compared with it. Finally, the results obtained are discussed, as well as other factors that are taken into account throughout the work. The study ends with some conclusions about the results and the objective of the proposed research., En el siguiente trabajo se explica un estudio aerodinamico, que consiste en ver la ínfluencia que tiene la superficie terrestre sobre la propagacion del viento. Concre- ´ tamente en llanuras, pendientes de subida y de bajada, geometrías basicas que ´ representan desniveles terrenales de zonas montanosas. Una vez el viento atraviesa ˜ los dominios mencionados, se analiza el perfil de velocidad resultante. Todo con tal de proporcionar evidencia científica a las investigaciones de la energía eolica, ´ mostrando las alturas en donde un aerogenerador aprovecha la maxima energ ´ ía cinetica del viento. Para hacerlo posible, se utiliza un programa libre y comercial én Dinamica de Fluidos Computacional (CFD) denominado OpenFOAM. En ´ el, se éspecifican las condiciones físicas de los contornos de cada geometría. Como la entrada del flujo, el terreno por donde se propaga, su salida y la limitacion superior. ´ Se examinan las condiciones de contorno y se concluyen cuales son las m ´ asádecuadas para la tesis. La rugosidad se simula mediante las “funciones de pared”, las cuales representan la obstaculizacion del terreno. La turbulencia que aparece en ´ consecuencia, se analiza mediante el modelo RANS, concretamente el de k-epsilon. ´ Y con tal de reducir factores que puedan aumentar dicha turbulencia, la velocidad de entrada que se impone es reducida. Conocimientos físicos sobre la Capa Límite Atmosferica se tienen en cuenta en él trabajo. Ademas de tener como referencia los estudios realizados por Richard ´ y Hoxey en el 1993, los cuales modelaron un perfil de velocidad teorico adaptado á las condiciones de la Capa Límite Atmosferica. Modelo que se usa como ve- ´ locidad teorica de cada simulaci ´ on, por lo que los resultados se comparar ´ an con ´ este. ´ Finalmente se discuten los resultados obtenidos, así como otros factores que se tienen en cuenta a lo largo del trabajo. El estudio termina con unas conclusiones sobre los resultados y el objetivo de la investigacion plante

To increase renewable energy generation in some hydroelectric dams, a solution consisting in installing wind turbines close to dams is proposed. Indeed, dam surroundings are prone to benefit from wind speed-up effect, extra wind generation associated with thermal winds, and existing electrical infrastructure. Identifying the most suitable locations for turbines, that is, areas of relatively high-speed and low-turbulence wind, is fundamental to maximize this complementary power. Easy accessibility to turbines and minimum distance to dam electrical infrastructure are also essential to reduce the costs. Thus, a methodology is proposed to improve wind resource assessment in complex mountainous areas. First, potentially interesting dams are chosen using statistical local wind data. Second, weighted results of wind speed and turbulence intensity, considering all wind directions are presented based on CFD simulations. Finally, wind power density and annual energy production maps are generated, along with accessibility maps, to identify suitable sites. The Camarasa dam in the north-east of the Iberian Peninsula is chosen as case study to show and test the proposed methodology. Error estimations are provided, along with validation against Wind Atlas data and WAsP simulations., Peer Reviewed, Postprint (published version)