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Concept# Vent

Résumé

Le vent est le mouvement d'une partie du gaz constituant une atmosphère planétaire située à la surface d'une planète. Les vents sont globalement provoqués par un réchauffement inégalement réparti à la surface de la planète provenant du rayonnement stellaire (énergie solaire) et par la rotation de la planète. Sur Terre, ce déplacement est essentiel à l'explication de tous les phénomènes météorologiques. Le vent est mécaniquement décrit par les lois de la dynamique des fluides, comme les courants marins. Il existe une interdépendance entre ces deux circulations de fluides.
Les vents sont généralement classifiés selon leur ampleur spatiale, leur vitesse (ex. : échelle de Beaufort), leur localisation géographique, le type de force qui les produit et leurs effets. La vitesse du vent est mesurée avec un anémomètre mais peut être estimée par une manche à air, un drapeau, etc. Les vents les plus violents actuellement connus ont lieu sur Neptune et sur Saturne.
Le vent est l'acteur principal

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CIVIL-441: Water ressources management

L'ensemble des problématiques liées à l'eau est présenté afin d'avoir une vue globale de la gestion et de l'économie de cet élément essentiel à toute vie et toute activité. L'analyse des ressources et des besoins est présentée ainsi que les outils d'optimisation et d'évaluation économique.

ENV-525: Physics and hydrology of snow

This course covers principles of snow physics, snow hydrology, snow-atmosphere interaction and snow modeling. It transmits sound understanding of physical processes within the snow and at its interfaces with the atmosphere and the ground, including field, laboratory, and modeling techniques.

ENV-400: Air pollution and climate change

A survey course describing the origins of air pollution and climate change

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Cyclone tropical

Un cyclone tropical est un type de cyclone (dépression) qui prend forme dans les océans de la zone intertropicale à partir d'une perturbation atmosphérique qui s'organise en dépression tropicale pu

Météorologie

La météorologie est une science qui a pour objet l'étude des phénomènes atmosphériques tels que les nuages, les précipitations ou le vent dans le but de comprendre comment ils se forment et évoluent

Cisaillement (météorologie)

vignette|upright=1.5|alt=Ciel bleu comportant quelques nuages épars|Nuages de type cirrus avec des signes de vents cisaillants en haute altitude
Le cisaillement du vent est une différence de la vitess

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The main objective of this thesis is to model a regatta in the America’s Cup, and more precisely the first leg of the race, where the two competing sailboats have to move upwind. During the race, each crew attempts to be the first to reach the end of this leg, and is allowed to hinder its opponent as long as certain rules are respected. A boat which finishes this leg first is often able to manage its lead until the end of the regatta. An essential ingredient of the problem is the study of different maneuvers that the boats can execute during the race, as well as the effect generated by the presence of a boat on the wind around it. Indeed, a boat located just behind its opponent will receive less wind in its sails, and its speed will consequently be reduced. The boats considered in our model are of the type Class America, which were in used in the America’s Cup between 1982 and 2007. The race can hence be viewed as a game between two players which are assumed to be identical, in which each of them can make decisions sequentially. The goal of each player is to finish the first upwind leg with the largest lead possible over the opponent. The boats progress in an environment in which the wind fluctuates unpredictably. Thus, the game is a sequential stochastic game, in which each player will try to determine a sequence of actions which is the most favorable on average. A mathematical study of this kind of game will be done, and a strategy will be built by using tools of dynamic programming. A theorem will prove that this strategy is optimal, in the sense that no player has interest to deviate from this strategy. The last part of this thesis consists of applying the mathematical study of sequential stochastic games in the context of a sailing regatta. Given the current positions of the boats as well as the current state of the wind, a set of available actions and reactions for the boats can be defined. Each choice will bring the boats up to some new positions, where a new decision process will begin in a new state of the wind. Once the rules of the game are established, the objective is to define an algorithm which allows to build a strategy which will be an approximation of the optimal strategy. The implementation of this algorithm could produce a tool for decision support, that the crew could use on board during the regatta.

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The goal of this Master thesis project was to design a methodology that helps to analyze a set of indicators that can support the decision-making process, by identifying energy strategies with a temporal horizon 2030-2050 in Cuba. Several sources of data and methodologies were used to fulfill the objective. The energy planning model created by Madrazo during her Ph.D. thesis was used as the main tool in this project. The hourly demand and the wind and solar capacity factors have been used as input data for this model. A post-processing module was created in R code, with the objective of analyzing the behavior of the six technical indicators that the model offers as output. The Principal Component Analysis (PCA) method was used as an exploratory method to identify cluster that later allowed studying in detail the particular characteristics of these indicators. Different graphics were used to visualize the performance of the technical indicators under different conditions, which allows us to propose the best energy strategies to ensure a secure and sustainable energy transition. The methods of “Levelized cost of energy” (LCOE) and the costs associated with the "engineering process design" allowed to assess the economic feasibility of some scenarios of energy transition identified as interesting for decision making. The current cost of the Cuban electro-energetic system was estimated and compared with the costs obtained for future scenarios simulated. After analyzing the behavior of the indicators in detail, it was identified as the most suitable transition scenario for Cuba, where 150% demand is covered by 90% intermittent energy and 10% wind energy. Also, no backup will be required under these conditions, which represents a considerable saving from the current costs required by an electric generation with fossil resources. The energy storage needs will be 0.05 TWh, and the “concrete towers” and “VOSS” technologies can be used in order to minimize installation and operation costs of these facilities.

2020When assessing the economic viability of a wind farm, the estimation of the on-site wind power potential is perhaps the most important step. The most common way of evaluating the wind power potential of an area of interest consists of making on-site measurements for a period of one year. In order to take account of the inter-annual variation of wind speed, the one year of data are normally correlated with data recorded at a reference site where long-term data (typically > 10 years) are available. A correlation analysis is formulated for the concurrent data sets at the reference and prediction sites. This correlation is then used to transform the long-term wind speed at the reference site to the long-term wind speed that would have been expected at the prediction site had long-term measurements been made at this site. An alternative approach is also used, which consists of establishing site-to-site relationships using a numerical model to simulate meteorological situations which are typical for the area of interest. These relationships are then used to transpose the known long-term wind statistics of the reference site to the prediction site. Such an approach is applied in this work to the region of Chasseral & Mt-Crosin. The wind data available for a period of 16 years at Chasseral are transposed to the Mt-Crosin site where they are then compared to the data measured at the location of the installed wind farm. Over complex terrain, the linearised models traditionally used for wind power potential assessment fail to reproduce accurate wind fields. Therefore, to be applied to mountainous terrain such as that found in Switzerland, the approach relying on numerical simulation requires the development and validation of a numerical tool capable of simulating wind fields over complex topography. As the numerical model would have to deal with relatively steep slopes requiring a fine horizontal (50-100 m) and vertical resolution (∼5-10 m in the lowest levels), a fluid dynamics model was used which solves the complete set of Navier-Stokes equations with κ-ε turbulence closure. The standard version of the model used (CFX4) is modified in a novel way to extend its field of application so that atmospheric phenomena could be simulated which are typical of the meso-scale. The modified version solves the flow equations with the anelastic approximation (deep Boussinesq) and assuming a background rotation of the wind field (with the high altitude wind field following the geostrophic approximation). In the first part of this work, the numerical model is validated. The results obtained in this phase show that for meteorological situations for which the wind at the ground is coupled to the high altitude wind, the numerical model is able to satisfactorily reproduce: the flow in the surface layer, reproducing the effects associated with the ground roughness, roughness change, or heat flux through the ground; the flow in the Ekman layer together with the interaction between the free flow thermal stability conditions and the boundary layer; the linear and non-linear effects associated with the perturbation induced by a mountain in a stably stratified flow. In the second stage of this work, an extension of the standard Measure-Correlate-Predict method is presented to calculate the wind speed distribution at the prediction site, from transposition relationships and from the wind statistics at the reference site. The validity of the underlying assumptions is confirmed using concurrent data sets that were collected at both the reference and prediction sites. To evaluate the accuracy that can be achieved with the transposition assumptions, a back-prediction is performed using the transposition relationships obtained using the observations. Different types of transposition relationships have been investigated. Finally, the transposition methodology is applied to calculate the wind speed conditions at Mt-Crosin from the Chassera1 data, using the transposition relationships calculated by the numerical model for a range of meteorological situations typical for the area considered. The Mt-Crosin to Chassera1 sector wind speed ratios calculated by the numerical model tend to slightly underestimate those observed. The mean wind speeds obtained from the transposition are underestimated by 7% to 18% at the three measuring mast locations on Mt-Crosin. The yearly energy output that can be produced by a wind turbine in these conditions is underestimated by 8% to 36%. For a further period, the actual energy production of the three installed wind turbines has been compared with the model prediction at hub height, which showed that the transposition results underestimate the actual yearly production by 22% to 24%. From the transposition of the long-term data at Chassera1 (16 years), with the relationships obtained by the numerical model, a wind power potential of between 470 MWh/year (Côte Est) and 596 MWh/year (Côte Nord) is predicted using the characteristics of a Vestas-V44 wind turbine. From the work presented here, it appears that for well-exposed sites such as those located along the Jura Crest, the methods developed are able to give a wind power potential prediction with a similar accuracy as a one year measurement campaign performed on site.