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Active gust load alleviation techniques exhibit a high potential in significantly reducing the transient gust loads on aircraft. In this work the aerodynamic potential of trailing-edge flaps and leading-edge flaps is numerically studied with the purpose to significantly reduce the structural gust loads. The utilized spanwise-segmented flaps represent slight modifications of existing devices for high-lift and maneuvering. The investigations based on unsteady Reynolds-averaged Navier–Stokes computations are conducted by employing a generic wing–fuselage aircraft configuration at transonic flow conditions. Idealized discrete “[Formula: see text]”-type vertical gusts that are relevant for the certification process are used as representative atmospheric disturbances. The focus of this paper is to introduce a practicable prediction method for required trailing- and leading-edge flap deflections for a significant mitigation of gust-induced wing loads. The three-dimensional flap deflections are determined by parametric two-dimensional simulations at representative wing sections. Different extensions of the estimation approach are investigated to assess the influence of the wing planform, the finite wing span, the aerodynamic phase lags, and the flap scheduling. It is shown that the trailing- and leading-edge flaps are promising in terms of alleviation of gust-induced wing bending and wing torsional moments, respectively. However, at high leading-edge flap deflections that are necessary for a full compensation of the wing torsional moment large-scale flow separation is identified. The introduced gust load alleviation approach indicates a good transferability between two-dimensional airfoil and three-dimensional wing aerodynamics for unsteady flap deflections.

Tropical storm Isaias (2020) moved quickly northeast after its landfall in North Carolina and caused extensive damage to the east coast of the United States, with electric power distribution disruptions, infrastructure losses and significant economic and societal impacts. Improving the real-time prediction of tropical storms like Isaias can enable accurate disaster preparedness and strategy. We have explored the configuration, initialization and physics options of the Weather Research and Forecasting (WRF) model to improve the deterministic forecast for Isaias. The model performance has been evaluated based on the forecast of the storm track, intensity, wind and precipitation, with the support from in situ measurements and stage IV remote sensing products. Our results indicate that the Global Forecasting System (GFS) provides overall better initial and boundary conditions compared to the North American Model (NAM) for wind, mean sea level pressure and precipitation. The combination of tropical suite physics options and GFS initialization provided the best forecast improvement, with error reduction of 36% and an increase of the correlation by 11%. The choices for model spin-up time and forecast cycle did not affect the forecast of the storm significantly. In order to check the consistency of the result found from the investigation related to TS Isaias, Irene (2011), Henri (2021) and Elsa (2021), three other tropical storms, were also investigated. Similar to Isaias, these storms are simulated with NAM and GFS initialization and different physics options. The overall results for Henri and Elsa indicate that the models with GFS initialization and tropical suite physics reduced error by 44% and 57%, respectively, which resonates with the findings from the TS Isaias investigation. For Irene, the initialization used an older GFS version and showed increases in error, but applying the tropical physics option decreased the error by 20%. Our recommendation is to consider GFS for the initialization of the WRF model and the tropical physics suite in a future tropical storm forecast for the NE US.

Vertical Axis Wind Turbines (VAWTs) have proven to be suitable for changing wind conditions, particularly in urban settings. In this paper, a 2D URANS (Unsteady Reynolds-Averaged Navier Stokes) numerical analysis is employed for an H-Darrieus VAWT. A turbulent domain is created through systemically randomising the inlet velocity to create macro-turbulence in front of the VAWT. The parameters for spatial and temporal randomisation of velocity and its effects on the turbine performance are studied for a mean free stream velocity, U∞ = 10 m/s, and a tip speed ratio (TSR) of 4.1. The mean Coefficient of power (Cp) for randomised fluctuation of 2 m/s and half-cycle randomisation update frequency is 0.411 and for uniform inlet velocity is 0.400. The Cp vs. Tip Speed ratio plot suggests that the optimal tip speed ratio for operation is around 4.1 for this particular wind turbine of diameter 1 m, chord 0.06 m, and NACA 0018 airfoils. The effect of randomisation for tip speed ratio λ = 2.5, 3.3, 4.1, and 5.3 on the performance of the turbine is studied. Turbine wake recovers at a faster rate for macro-turbulent conditions and is symmetric when compared to wake generated by uniform velocity inlet. The maximum velocity deficit for a distance behind the turbine, x/d = 8 at TSR (λ) = 4.1 is 46% for randomised inlet and 64% for uniform inlet. The effect of randomisation for λ = 2.5 to 5.3 on the performance of the turbine is analysed. A time-varying gust based on International Electrotechnical Commission (IEC) Extreme Operating Gust is used to study the effect of fluctuating wind conditions in a turbulent environment. Since real-time conditions often exceed gust factors mentioned by IEC, winds with large gust factors such as 1.50, 1.64, and 1.80 are analysed. With an increase in gust amplitude, Ugust = 6 m/s to Ugust = 12 m/s on a free stream velocity of U∞ = 10 m/s, the mean Cp decreases from 0.41 to 0.35 since the wind turbine operates under tip speed ratios outside optimal range due to large fluctuations in incoming velocity.

The study of unsteady aerodynamic phenomena in wind tunnels is supported by gust-generating devices capable of generating adjustable magnitude and periodicity velocity fluctuations in a flowfield. Gusts are typically generated actively by introducing moving vanes to direct the flow, or passively by tailoring the boundary layer growth and shape in the tunnel. The flow facility used here is a student-built closed-return low-speed wind tunnel, with a test section size of 750 mm × 750 mm and a maximum speed of 25 m/s. A two-vane gust generator utilizing NACA0018 airfoil sections of 150 mm chord length was designed and installed upstream of the test section. The flowfield was mapped with the installed vanes with and without gust actuation, utilizing a hot wire system. The tunnel with gust vanes exhibits a spatially uniform baseline turbulence intensity of 5%, with a steady state velocity deficit of 1 m/s in the vane–wake region. Upon introducing the gusting conditions at vane deflection angles of up to ±45°, velocity differences of up to 4 m/s were attained at 18 m/s freestream velocity at oscillation frequencies ranging between 1 Hz and 2 Hz.

There is a growing desire to operate Uncrewed Air Vehicles (UAVs) in urban environments for parcel delivery, and passenger-carrying air taxis for Advanced Air Mobility (AAM). The turbulent flows and gusts around buildings and other urban infrastructure can affect the steadiness and stability of such air vehicles by generating a highly transient relative flow field. Our aim is to review existing gust models, then consider gust encounters in the vicinity of buildings as experienced by flight trajectories over the roof of a nominally cuboid building in a suburban atmospheric boundary layer. Simplified models of fixed- and rotary-wing aircraft are used to illustrate the changes in lift and thrust experienced by flight around the building. The analysis showed that fixed-wing aircraft experienced a substantial increase in angle of attack over a relatively short period of time (

Sweet taste perception is a key factor in the establishment of the food pattern with nonstatic thresholds. Indeed, taste sensitivity can be influenced by physiological factors (age and sex), pathologies (obesity and type 2 diabetes mellitus), and acquired habits (tobacco and alcohol consumption). In order to elucidate how these variables influence the sucrose detection threshold (DT) and recognition threshold (RT), a systematic review and meta-analysis of the relevant literature were performed. After a comprehensive search in the PubMed and Scopus databases, a total of 48 studies were qualitatively considered, and 44 were meta-analyzed. The factors of aging (standard mean difference [SMD]: -0.46; 95% confidence interval (CI), -0.74 to -0.19; I2 : 73%; Tau2 : 0.18) and type 2 diabetes mellitus (SMD: 0.30; 95% CI, 0.06 to 0.55; I2 : 0%; Tau2 : 0.00) were found to significantly increase the sucrose RT, whereas the DT only increased in subjects with a higher body mass index (SMD: 0.58; 95% CI, 0.35 to 0.82; I2 : 0%; Tau2 : 0.00). No effects of sex and tobacco smoking were found, and associations with alcohol consumption could not be assessed, as it was included as a variable in only one study. Feasible mechanisms underlying changes in sucrose thresholds include the modulation of hormones involved in energy and body weight homeostasis, taste bud abundance, taste brain signaling, and the gut-brain axis. The present work provides insights into the variables that should be considered when assessing sweet taste sensitivity, discusses the mechanisms underlying differences in sweet taste, and highlights the need for further research in the field of personalized nutrition.

Aims: Taste dysfunction is a frequent complaint in head and neck cancer patients treated with Radiation Therapy (RT), which impairs nutritional support and affects quality of life. A prospective unicenter pilot study was conducted to assess taste dysfunction of the four basic tastes (sweet, salty, bitter, sour) and umami in four patients receiving RT for head and neck cancer. Methods: In four male patients (mean age 56 years) diagnosed with squamous cell carcinoma of the larynx (n= 2) and hypopharynx (n= 1) and undifferentiated carcinoma of the nasopharynx (n= 1), Volumetric Modulated Arc Therapy (VMAT) was administered with a total dose of 69,9 Gy on the tumor (2,12 Gy per fraction) and 54,12 Gy on risk lymph node areas at risk of suclinical disease (1,64 Gy per fraction), five times each week for 7 weeks. Cisplatin chemotherapy was administered for 3 cycles (every 21 days). The filter-paper disc was used to assess thresholds of sweet, salty, bitter, sour tastes, and the whole-mouth taste method for umami. Testing was performed before RT, at 3 weeks (during RT), at 6 weeks (during RT), at 12 months (after RT) and at 14 months (after RT). Results: The four basic tastes experienced a decrease in their recognition threshold at 3 and 6 weeks as compared with pre-RT values, but at 12 and 14 months values were similar to those before treatment. The perception of the umami taste follows a pattern similar to the four basic tastes and normalized from the year of starting radiotherapy. Conclusion: In the long-term, pilot study, the four basic tastes and umami declined during the first 6 weeks after the start of RT but improved up to pre-treatment values after a follow-up of 14 months. Restoration of test abilities is clinically relevant for head and neck cancer patients treated with RT. info:eu-repo/semantics/acceptedVersion

The behavior of the aircraft within turbulent atmosphere is a key aspect of design. Many books and articles deal with this topic. The current paper presents studies related to predicting the responses of aircraft flying through vertical gusts. The equations describing the dynamics of the longitudinal channel of the airplane are written to include the effect of the vertical wind. The paper includes comparisons of results provided by non-linear and linearized equations of motion.

En el context de l'artificació de la cuina, aquesta investigació se centra en el paper del comensal. Algunes de les innovacions de la Nouvelle Cuisine, intensificades per la cuina tecno-emocional, ajuden a considerar-li com un espectador i donen lloc a una teoria de l'art de menjar. No obstant això, en assumir el seu cos com a suport de la representació, les condicions gustativas difícilment es poden explicar. Els límits de la teoria hilemòrfica, assenyalats per Simondon, eviten la consideració del procés i preveien un subjecte descorporeizat que fa ús del seu cos (Agamben) sense tenir-hi cura. Tant en les pràctiques gustatives (commensitat i convivilitat) com en el pensament filosòfic sobre el gust, es detecta una censura del cos per una paraula compromesa amb aquest subjecte. El gust és l'origen exclòs de l'experiència estètica en la mesura que el seu 'je ne sais quoi' es refereix a la frontera de la definició d'aquest subject, la raó del qual és visual. A partir d'aquí, el cos és el fons animal des del qual convertir-se en figura. Un canvi en el concepte de representació, que defineix la figuració com una exploració amb el nostre cos, pot mostrar otra manera en què les paraules participen en la creació comuna de significat. En l'últim capítol, es presenta un intent de que la paraula gustativa sigui, juntament amb definicions contemporànies del cos, el gust, el subjecte, l'art i el temps, entre altres. L'analogia entre menjar i lectura (Derrida) i la plasticitat del subjecte quan llegeix (Malabou) es considera en el seu estil. Tot el text està acompanyat pel repositori de les més de cent obres d'art que tracen el fil discurs d'aquesta investigació. En el contexto de la artificación de la cocina, esta investigación se centra en el papel del comensal. Algunas de las innovaciones de la Nouvelle Cuisine, intensificadas por la cocina tecnoemocional, ayudan a considerar al comensal como espectador y dan pie a una teoría del arte de comer. Sin embargo, al asumir su cuerpo como soporte de la representación, las condiciones gustativas difícilmente pueden ser explicadas. Los límites de la teoría hilemórfica, tal como los señaló Simondon, impiden una consideración del proceso y prevalecen un sujeto incorpóreo que hace uso de su cuerpo (Agamben) sin atender a él. Tanto en las prácticas gustativas (comensalidad y convivencia) como en el pensamiento filosófico sobre el gusto, se detecta la cesura del cuerpo por una palabra comprometida con este sujeto. El gusto es el origen excluido de la experiencia estética en tanto su 'je ne sais quoi' remite a la frontera de la definición del sujeto cuya razón es visual. A partir de ahí, el cuerpo es el fondo animal a partir del cual devenir figura. Un giro en el concepto de representación, que define la figuración como una exploración con nuestro cuerpo, puede mostrar otro camino por el que las palabras participen en la creación común de sentido. En el último capítulo se presenta un intento de dejar ser una palabra gustativa, de la mano de definiciones contemporáneas de cuerpo, gusto, sujeto, arte y tiempo, entre otras. En su estilo se considera la analogía entre comer y leer (Derrida) y la plasticidad del sujeto mientras lee (Malabou). Todo el texto va acompañado de un repositorio con las más de cien obras de arte que trazan el hilo discursivo de esta investigación. In the context of the artification of cooking, this research focuses on the role of the diner. Some of the innovations of Nouvelle Cuisine, intensified by techno-emotional cuisine, help to consider the diner as a spectator and give rise to a theory of the art of eating. However, by assuming the body as the support of representation, the gustatory conditions can hardly be explained. The limits of the hylemorphic theory, as Simondon pointed out, prevent the consideration of the process and foresee a disembodied subject who makes use of his body (Agamben) without attending to it. Both in gustatory practices (commensality and conviviality) and in philosophical thought on taste, one detects a censorship of the body by a word committed to this subject. Taste is the excluded origin of aesthetic experience in so far as its 'je ne sais quoi' refers to the border of the definition of the subject whose reason is visual. From there, the body is the animal background from which to become a figure. A change in the concept of representation, which defines figuration as an exploration with our body, can show a way in which words participate in the common creation of meaning. In the last chapter, an attempt to 'let the gustative word be' is presented, hand in hand with contemporary definitions of body, taste, subject, art and time, among others. The analogy between eating and reading (Derrida) and the plasticity of the subject when reading (Malabou) are considered in its style. The entire text is accompanied by the repository of the more than one hundred works of art that trace the discursive thread of this research.

Approach and landing phases take less than 4% of total flight time of a typical flight, but 36% of fatal aircraft accidents occur during this phase. Gust disturbances creating uncertainties during this phase are primary contributors to many unstabilized, high and fast approaches leading to catastrophic ending. This study analyses the effects of gust and resulting responses affecting the handling and flying characteristics of an aircraft during landing. A pilot-in-the-loop flight simulation during landing with the effect of gust was developed using Boeing B747-100 aircraft to analyze the problem. Elevator and throttle inputs through a joystick were used as control inputs to allow the pilot-in-the-loop to control the aircraft glide-path and speed during landing. It was found that the aircraft flight path during the descent is not affected, if the frequency of the gust is higher than the natural frequency of the aircraft, but maintaining the flight glide path becomes difficult for lower frequencies. Likewise, the vertical gust has more prominent effect than the horizontal gust. In both cases, the aircraft susceptibility to gust disturbances increases the pilot workload causing more difficulties for a landing.

The paper describes and analyses potential concepts for gust alleviation at transonic speeds applied on a forward swept transport aircraft configuration. The main objective is to reduce structural weight by minimizing gust induced loads. Both inviscid and viscous aerodynamic simulations are performed for analysis. A gust study reveals a critical gust wave length of 50m leading to highest aerodynamic loads at cruise conditions. Gust induced separation is observed for particular cases. Deflection of a wing tip flap and the aileron at the outer wing have a remarkable short response time and offer strong flow actuation to reduce gust loads.

Gust is a common atmospheric turbulence phenomenon encountered by aircraft and is one major cause of several undesired instability problems. Although the response of aircraft to the incoming gust has been widely investigated within the subject of external-flow aerodynamics in the past decades, little attention is paid to its effects on the internal flow within aircraft engines. In this paper, a newly implemented Field Velocity Method (FVM) in OpenFOAM is used to simulate the flow field and aerodynamic responses of a serpentine inlet exposed to non-stationary horizontal sinusoidal gusts. Validations are performed on the results obtained based on the baseline Computational Fluid Dynamics (CFD) solver and the gust modeling method. Finally, the flow field and aerodynamic characteristics of the serpentine inlet under horizontal sinusoidal gust conditions are comprehensively investigated. It is found that the gusts not only significantly change the flow structure but also play an unfavorable role in the total pressure distortion of the serpentine inlet. This finding shows the necessity to consider gust effects when designing and evaluating the performance of aircraft engines.

This study investigated the severe winds occurred in the Kinki District and the surrounding areas during the passage of Typhoon Jebi (2018) that developed in September 2018. This typhoon has induced currently the most costly meteorological damages to Japan. The analyses of the surface observational data indicated that the gust factors in urban areas amount to 2.0 or greater, which are significantly higher than those typically known at meteorological stations in a climatological sense. The coupled analysis of both a mesoscale meteorological model and a large-eddy simulation model demonstrated that the maximum wind gust in the analysis area of Osaka City was estimated as 60-70 m/s, which is comparable to the wind speed at the height of about 300 m.

International audience; Powerful storms, consisting of strong gusts and winds, damage forests. Therefore, foresters need forest management strategies to reduce the damage risk. This paper focused on the damage patterns within the forest as the final results of multiple tree-wind dynamic interactions in time and space during a storm. Recent developments in computer technology allow for the possibility of simulating the complex and dynamic phenomena of damage during a storm but are extremely time consuming. To simplify the simulations without losing the crucial aspects of wind damage in forests, we introduced a computer simulation model using the agent-based modelling (ABM) technique, which capture the phenomena and interactions of individuals called ‘agents’. We created an ABM for forest wind damage simulation, coupling together an accepted understanding of wind gusts in forests, tree bending moments, and damage propagation. The model was tested with variations in three conditions: trees acclimated and unacclimated to their wind environment; three levels of gust strength; and three tree planting densities. The ABM was able to replicate damage patterns and demonstrate damage propagation within the forest and the effects of forest edges. The difference in the rate of damage in the forest between acclimated and unacclimated edges became similar with an increase in the gust intensity, and a decrease in tree density through a reduction in the shelter effect of the forest. The ABM could be improved in the future by parametrizing the variation in individual tree resistance, and the variation in gust and wind strength, as well as adding more information on local environmental conditions such as topography and soil variation, and storm characteristics such as duration and intensity.

The transient surface pressure over a full-scale, operational compact automotive vehicle—a Volkswagen Golf 7—exposed to transient crosswinds with relative yaw angles of β = 22-45° has been characterized. Experiments were performed at the BMW side-wind facility in Aschheim, Germany. Measurements of the incoming flow in front of the car were taken with eleven five-hole dynamic pressure probes, and separately, time-resolved surface pressure measurements at 188 locations were performed. Unsteady characteristics (not able to be identified in quasi-steady modelling) have been identified: the flow in separated regions on the vehicle’s leeward side takes longer to develop than at the windward side, and spatially, the vehicle experiences local crosswind as it gradually enters the crosswind. The total effects of these localized unsteady pressure characteristics have also been predicted to affect the vehicle globally, with the evaluation of the transient forces and moments—through pressure integration—exhibiting unsteady characteristics of overshoots, undershoots, and temporal lag; relative to steady crosswind. These results provide new insight into both the characteristics and the causes of the unsteady crosswind response of a real, operational vehicle operating in real-world conditions. This insight can be used in the design of future vehicles to make them less sensitive to unsteady gusts. Further these results can be used to develop and validate numerical and reduced-scale experimental methods that can test and assess new vehicle geometry designs during the early stages of vehicle development.

Typhoons, such as Soudelor, which caused the collapse of several onshore wind turbines in 2015, pose a considerable challenge to Taiwan’s wind energy industry. In this study the characteristics of the aerodynamic loads acting on a wind turbine due to wind gusts in a typhoon are studied with a view to providing a proper definition of the S-Class wind turbine proposed in International Electrotechnical Commission (IEC) 61400-1. Furthermore, based on analysis of wind data during typhoons, as obtained from the meteorological mast in the Zhangbin coastal area, an extreme wind speed and gust model corresponding to the typhoon wind conditions in Taiwan are herein proposed. Finally, the flow fields around a parked wind turbine experiencing both an unsteady gust and a steady extreme wind were simulated by a numerical approach. Numerical results show that the aerodynamic shear force and overturning moment acting on the target wind turbine in a steady wind are significantly lower than those under an unsteady gust. The gust-induced amplification factors for aerodynamic loadings are then deduced from numerical simulations of extreme wind conditions.

Large-scale wind turbines often face the problem of tower clearance safety under extreme gust conditions. Since gust intensity is positively correlated with the change rate of the generator’s speed, a gust identification method is proposed based on wind turbine monitoring data. Furthermore, a novel tower clearance safety protection strategy is proposed, which superimposes some additional speed requirements on the basis of normal pitch rate when identifying extreme gust so as to alleviate the dynamic response of the wind turbine. Simulations and comparison of a 5 MW wind turbine, before and after applying the new strategy, showed that the new strategy can induce an increase in pitch angle for the wind turbine and, simultaneously, avoids the emergency stop caused by the generator’s overspeed. Meanwhile, when the new strategy is adopted, the blade tip’s deformation and the load on the top of the tower are reduced by 19.9% and 52.2%, respectively. Therefore, the proposed strategy can not only protect the safety of the wind turbine but it also reduces costs.

El gusto es la categoría en que la estética burguesa que emergió en el siglo XVII formula la promesa de autonomía para reconciliar sin fisuras la forma de la subjetividad con la exigencia de objetividad. Esta promesa de autonomía fue anulada por el capitalismo de consumo de masas y substituida por el gusto como medio para la adaptación creativa. Esto plantea la cuestión por un «gusto distinto» a la vez más allá de la autonomía burguesa y la adaptación consumista. Esta es la idea de gusto como pasión (pathos) o Kraft -como «aversión» (Adorno). Taste is the category in which the bourgeois aesthetics that emerged in the 18th century formulates the promise of autonomy to reconcile without fissures the form of subjectivity with the claim to objectivity. This promise of autonomy was canceled by the capitalism of mass consumption and replaced by the taste as the medium for creative adaptation. This poses the question of a «different taste» beyond bourgeois autonomy and consumerist adaptation at the same time. This is the idea of taste as passion (pathos) or Kraft -as «reluctance» (Adorno).

International audience; In the context of random environment, time-domain simulation of structural responses is often necessary when the structure is nonlinear, but not only: when the structure is linear and the excitation modelled as a non-stationnary non-Gaussian process, Monte Carlo approaches are necessary to identify the probabilistic distribution of the output. In this paper we use a stochastic model developped for non-stationnary and non- Gaussian random processes. It is based on an empirical Karhunen-Loeve expansion of the process constructed from an available data basis. We study the particular case of linear structures: the Monte Carlo becomes particularely simple: one needs only to consider the construction of a low number of responses, corresponding to the deterministic eigen functions of the Karhunen-Loeve expansion, hence avoiding high number of calls to industrial codes. The KL expansion of the response is then obtained directly using these responses and the system output probabilistic characterization can be constructed through Monte Carlo simulation of the KL output model. This approach is usedin order to quantify the effect of gusts on a future airship using a database obtained during a winter storm from which a model of vertical gusts is constructed. Response comparisons for realistic and gusts and the one prescribed by national regulation requirements will be shown.; Afin de caractériser la réponse d'un dirigeable aux rafales réelles, on construit dans un premier temps un modèle probabiliste de ces rafales basé sur un développement de Karhunen Loève construit à partir d'une base de donnée du vent.Puis en utilisant la linéarité du code aérodynamique utilisé pour calculer la réponse à la rafale on identifie le modèle probabiliste de la sortie, par exemple le facteur de charge. Ce modèle probabiliste est en fait le développement de Karhunen Loève de la sortie, qui peut alors être utilisé pour générer des simulations additionnelles ouvrant la voie à une approche de Monte Carlo permettant de la caractériser.

The Loads Kernel Software allows for the calculation of quasi-steady and dynamic maneuver loads, unsteady gust loads in the time and frequency domain as well as dynamic landing loads based on a generic landing gear module. This report is a published copy of the Loads Kernel User Guide, Version 1.01 as of 11. January 2021.

The prediction of the aircraft response to gust and turbulence is of major importance for different purposes. Gust load analysis is an essential part of aircraft design and certification. The effect of gust and turbulence on aircraft flight dynamics is also of interest. Models able to capture relevant effects at these conditions in early design phases are essential in order to anticipate and assess the aircraft response and flight control laws in realistic atmospheric disturbances before flight test. This work proposes a modelling strategy to capture relevant physics when simulating the aircraft response to gust and turbulence for flight dynamics investigations. The model provides accuracy at a low computational cost as well as consistency with gust loads analysis enabling multidisciplinary design. The approach is based on the integration of a nonlinear quasi-steady flexible flight dynamics model with an unsteady aeroelastic model linearized around a nonlinear steady state. The gust-induced forces have a significant impact on aircraft flight dynamics. Low computing times are required to cover several flight conditions and aircraft parameters. A computationally efficient multipoint aerodynamic model, which captures both unsteady aerodynamic and gust propagation effects, is generated from linearized Computational Fluid Dynamics (CFD) simulations in the frequency domain. The model is identified through a rational function approximation allowing for time domain simulations. A reduced number of additional aerodynamic states is sufficient to capture the main effects at low frequencies for flight dynamics analysis. The impact of dynamic flexibility on the response is also evaluated. Only the most energetic flexible modes are retained to reduce the number of states and ensure a low computation time. The approach is applied to simulate the vertical and lateral response of a passenger aircraft to theoretical disturbance profiles as well as realistic atmospheric turbulence at different flight conditions. Aerodynamic nonlinear effects, such as local stalls due to shock motion, in transonic conditions may appear. The linearized model is able to capture the global aircraft response at these conditions with low amplitude shock motions. Results are compared and validated with a CFD simulation based approach, coupled with a structural dynamics and flight mechanics solver. Measures from flight test are also used to assess the modelling approach. The effect of uncertainties on the response is analysed, in terms of the turbulence variation along the wingspan. Simulation results show that relevant aerodynamic effects due to gust and turbulence are captured in the frequency range of interest for flight dynamics investigations.

International audience; In the present work, the optimal control to maximize the energy harvesting through a sinusoidal vertical gust profile is investigated through 2D URANS simulations and wind tunnel tests of NACA 0015 wing. The control is defined by a harmonic pitching motion of the wing, with the main objective to determine the optimal control parameters represented by the optimal pitch amplitude and phase shift that maximize the energy harvesting efficiency. The computational fluid dynamics (CFD) based on the k-omega -SST turbulence model is implemented to find the optimal control parameters for a simultaneously heaving and pitching 2D wing. For the experimental investigation, a wind tunnel model is manufactured and used to perform the wind tunnel tests to prove the energy harvesting concept and validate the obtained CFD results. Since it wasn't feasible to generate sinusoidal vertical gust in the wind tunnel, the gust effect is modeled by a sinusoidal heaving motion of the wing. A robotic arm is used to perform the simultaneous heaving and pitching motions of the wing. The numerical results showed the significant effect of the control activation to increase the energy harvesting where an optimal efficiency of 67 % is achieved at a gust amplitude of 0,5 m/s and frequency of 0,4 Hz. It was also found that an increase in the amplitude of the sinusoidal gust profile brings significant increment in the amount of energy harvested. Wind tunnel tests proved the concept of energy harvesting and exhibit the same trends of efficiency variation with pitch amplitude as that obtained through the numerical simulations. The obtained results showed that the energy harvesting flight technique is very promising regarding the improvement of the performance of mini-UAVs.

A method is presented, that is able to mitigate gust loads on an airfoil induced by an incoming gust velocity field. It thereby computes the lift coefficient response to a specified arbitrary gust velocity profile and predicts the required time-accurate control surface deflection. The method uses the linear frequency domain solver to predict frequency responses for the gust and control surface derivative of the lift coefficient efficiently. The frequency responses are computed and then subsequently filled as samples into a surrogate model. For a new flight condition the surrogate model predicts the frequency response by mere interpolation. Because the aerodynamic response on the gust and the behavior of the control surface are known, the aerodynamic lift response and the required flap deflection for alleviation can both be predicted from a given gust velocity field. The method is thereby able to predict the aerodynamic response and a time-accurate deflection for any flight condition in the design space within milliseconds. Results of the method are shown and analyzed on a 2D profile of a transonic airfoil with an implemented plain flap. The parameter studies were made in low speed with variation of Mach number, Reynolds number, angle of attack, flap chord size and initial flap deflection. In comparison to unsteady Reynoldsaveraged Navier-Stokes computations, the presented method can predict the aerodynamic responses with the same accuracy and it saves more than 6 orders of magnitude in computation time. Using the linear frequency domain solver it is also able to predict the arising unsteady aerodynamic behavior and still cover the viscous effects in the flow.

Flexible structures such as cable-stayed bridges are subject to dynamic wind loads. These are usually divided into two categories, flutter which is a motion-induced load and buffeting, which is generally considered as an uncoupled load. When these two phenomena are intertwined, it becomes difficult to use spectral methods and time simulation represents a relatively new and promising alternative.The most difficult challenge is to simulate the torsional stall flutter caused by additionnal damping. However, this phenomenon, which was responsible for the collapse of Tacoma narrow bridge, is still central to the design of civil engineering structures. This study is based on the development of a new temporal formulation of the motion-induced pitch moment, which can be easily combined with representations of the unsteady effects of wind. The construction of the new aeroelastic model is based on the introduction of a time delay between the instantaneous position of the studied deck and the aerodynamic forces.The validation of the model is provided by wind tunnel tests. They are carried out with elastically supported sectional models, subject to the effects of a steady wind, those of a gust, as well as those of a highly turbulent wind. Three sections are considered, stable or unstable: the Millau Bridge, the Tacoma Bridge and a NACA-4412 airfoil.; Les structures flexibles telles que les ponts à haubans sont soumises aux effets dynamiques du vent. Ceux-ci sont habituellement divisés en deux catégories, les flottements qui induisent une réponse couplée avec le mouvement et l’excitation par la turbulence qui est généralement traitée comme découplée du mouvement. Lorsque ces deux phénomènes s’entremêlent, il devient délicat d'employer les méthodes spectrales usuelles. Les modèles temporels représentent alors une alternative intéressante, dont l’enjeu majeur consiste à simuler le flottement de décrochage en torsion par amortissement ajouté. Or ce phénomène, notamment mis en cause dans l’accident du pont de Tacoma, est encore aujourd’hui central lors de la conception des ouvrages d’art.La présente étude s’articule autour du développement d’une nouvelle formulation temporelle du moment de tangage induit par le mouvement, qui peut facilement être combinée avec les représentations usuelles des effets instationnaires du vent. L'approximation quasi-statique qui est habituellement utilisée pour modéliser le flottement en galop vertical des corps non profilés, conduit à négliger les effets de mémoire du fluide, qui sont particulièrement importants pour prédire le flottement de torsion. La clef de voute de la construction du nouveau modèle aéroélastique est l’introduction d’un temps de retard « τ » entre la position instantanée du tablier étudié et les efforts aérodynamiques. Cette stratégie permet ainsi de compenser en partie les limites de l’approche quasi-statique afin de simuler l’amortissement aérodynamique induit par le mouvement, tout en capturant de manière élégante la physique du phénomène.Dans un premier temps, une procédure d’identification des valeurs de « τ » mettant en œuvre les dérivées de flottement A_2^* et A_3^* de Scanlan est proposée, et le sens physique de ce paramètre est discuté. Enfin, un critère linéaire très simple de stabilité au flottement, basé uniquement sur la pente du coefficient de tangage C_M^', est établi et validé pour les tabliers de ponts. Le paramétrage du modèle ne requiert donc que les résultats expérimentaux classiques habituellement utilisés en ingénierie du vent et des structures, à savoir les dérivées du flottement et les coefficients aérodynamiques des sections.Le bon fonctionnement du modèle est validé en soufflerie avec des maquettes de tablier élastiquement supportées, soumises aux effets du vent stationnaire, d’une rafale, ainsi qu’à ceux d’un vent fortement turbulent. Trois sections types, stables ou instables, sont considérées : le pont de Millau, le pont de Tacoma et une aile NACA-4412. Les réponses en régimes transitoires et quasi-permanents sont prédites avec précision, et sont en bon accord avec les mesures expérimentales. Cette formulation temporelle à retard s’avère donc prometteuse et se positionne comme alternative crédible aux approches spectrales et hybrides, fondées sur les dérivées du flottement ou les fonctions indicielles, à ce jour plus répandues.

Flexible structures such as cable-stayed bridges are subject to dynamic wind loads. These are usually divided into two categories, flutter which is a motion-induced load and buffeting, which is generally considered as an uncoupled load. When these two phenomena are intertwined, it becomes difficult to use spectral methods and time simulation represents a relatively new and promising alternative.The most difficult challenge is to simulate the torsional stall flutter caused by additionnal damping. However, this phenomenon, which was responsible for the collapse of Tacoma narrow bridge, is still central to the design of civil engineering structures. This study is based on the development of a new temporal formulation of the motion-induced pitch moment, which can be easily combined with representations of the unsteady effects of wind. The construction of the new aeroelastic model is based on the introduction of a time delay between the instantaneous position of the studied deck and the aerodynamic forces.The validation of the model is provided by wind tunnel tests. They are carried out with elastically supported sectional models, subject to the effects of a steady wind, those of a gust, as well as those of a highly turbulent wind. Three sections are considered, stable or unstable: the Millau Bridge, the Tacoma Bridge and a NACA-4412 airfoil.; Les structures flexibles telles que les ponts à haubans sont soumises aux effets dynamiques du vent. Ceux-ci sont habituellement divisés en deux catégories, les flottements qui induisent une réponse couplée avec le mouvement et l’excitation par la turbulence qui est généralement traitée comme découplée du mouvement. Lorsque ces deux phénomènes s’entremêlent, il devient délicat d'employer les méthodes spectrales usuelles. Les modèles temporels représentent alors une alternative intéressante, dont l’enjeu majeur consiste à simuler le flottement de décrochage en torsion par amortissement ajouté. Or ce phénomène, notamment mis en cause dans l’accident du pont de Tacoma, est encore aujourd’hui central lors de la conception des ouvrages d’art.La présente étude s’articule autour du développement d’une nouvelle formulation temporelle du moment de tangage induit par le mouvement, qui peut facilement être combinée avec les représentations usuelles des effets instationnaires du vent. L'approximation quasi-statique qui est habituellement utilisée pour modéliser le flottement en galop vertical des corps non profilés, conduit à négliger les effets de mémoire du fluide, qui sont particulièrement importants pour prédire le flottement de torsion. La clef de voute de la construction du nouveau modèle aéroélastique est l’introduction d’un temps de retard « τ » entre la position instantanée du tablier étudié et les efforts aérodynamiques. Cette stratégie permet ainsi de compenser en partie les limites de l’approche quasi-statique afin de simuler l’amortissement aérodynamique induit par le mouvement, tout en capturant de manière élégante la physique du phénomène.Dans un premier temps, une procédure d’identification des valeurs de « τ » mettant en œuvre les dérivées de flottement A_2^* et A_3^* de Scanlan est proposée, et le sens physique de ce paramètre est discuté. Enfin, un critère linéaire très simple de stabilité au flottement, basé uniquement sur la pente du coefficient de tangage C_M^', est établi et validé pour les tabliers de ponts. Le paramétrage du modèle ne requiert donc que les résultats expérimentaux classiques habituellement utilisés en ingénierie du vent et des structures, à savoir les dérivées du flottement et les coefficients aérodynamiques des sections.Le bon fonctionnement du modèle est validé en soufflerie avec des maquettes de tablier élastiquement supportées, soumises aux effets du vent stationnaire, d’une rafale, ainsi qu’à ceux d’un vent fortement turbulent. Trois sections types, stables ou instables, sont considérées : le pont de Millau, le pont de Tacoma et une aile NACA-4412. Les réponses en régimes transitoires et quasi-permanents sont prédites avec précision, et sont en bon accord avec les mesures expérimentales. Cette formulation temporelle à retard s’avère donc prometteuse et se positionne comme alternative crédible aux approches spectrales et hybrides, fondées sur les dérivées du flottement ou les fonctions indicielles, à ce jour plus répandues.

A quasi-steady doublet-lattice correction method is used to predict aerodynamic gust responses of two different configurations: a swept wing, the so-called Aerostabil wing, and a transport aircraft configuration, the NASA Common Research Model. The results of the correction method are compared to uncorrected doublet-lattice results, and to results obtained from a nonlinear computational fluid dynamics solver, the DLR TAU-Code. The correction method agrees well with time-marching results obtained by TAU in the limit of dynamically linear gust amplitudes and improves with gust length. In separated transonic flow, an oscillation of the aerodynamic gust response can be computed.

En les darreres dècades s'ha detectat un increment, a nivell mundial, de malalties cròniques relacionades amb una mala alimentació. Governs, institucions i organismes públics de la mà de científics i investigadors, cerquen solucions per modificar els hàbits de la població cap a comportaments alimentaris saludables. D'aquesta necessitat, en neix una nova disciplina coneguda com a neurogastronomia. Aquest treball, és una revisió bibliogràfica per conèixer què és i quina aplicació té aquesta ciència. Els resultats indiquen com les investigacions revisades tenen en comú la intervenció de diversos professionals amb diferents coneixements i sensibilitats (neuròlegs, psicòlegs, antropòlegs, sociòlegs, cuiners, nutricionistes i dietistes, tècnics d'alimentació...) que donen llum als factors invisibles (inconscients) que afecten d'una manera significativa al comportament alimentari i conseqüentment, a la salut. En el cervell es combina la informació de les propietats del menjar i l'entorn, que provenen de tots els sentits (gust, vista, oïda, olfacte i tacte) i que creen el sabor des de les diferents experiències sensorials que determinen les preferències de consum. Les noves polítiques de nutrició públiques comencen a aplicar les descobertes en neurogastronomia, millorant així l'atractiu dels aliments i la percepció de plaer en els aliments saludables menys desitjats; gràcies als coneixements de la nova disciplina sobre el control dels factors inconscients que envolten l'experiència del menjar. Així doncs, s'estan obrint línies d'investigació i recerca en aquest camí per aconseguir frenar les malalties per la mala alimentació o disminuir el temps de recuperació d'aquestes malalties i convertir-ho en una fita obligada en el món de la nutrició i la salut. En las últimas décadas se ha detectado un incremento, a nivel mundial, de enfermedades crónicas relacionadas con una mala alimentación. Gobiernos, instituciones y organismos públicos de la mano de científicos e investigadores, buscan soluciones para modificar los hábitos de la población hacia comportamientos alimentarios saludables. De esta necesidad, nace una nueva disciplina conocida como neurogastronomía. Este trabajo, es una revisión bibliográfica para conocer qué es y qué aplicación tiene esta ciencia. Los resultados indican cómo las investigaciones revisadas tienen en común la intervención de varios profesionales con diferentes conocimientos y sensibilidades (neurólogos, psicólogos, antropólogos, sociólogos, cocineros, nutricionistas y dietistas, técnicos de alimentación ...) que dan luz a los factores invisibles ( inconscientes) que afectan de una manera significativa el comportamiento alimentario y consecuéntemente, la salud. En el cerebro se combina la información de las propiedades de la comida y el entorno, que provienen de todos los sentidos (gusto, vista, oído, olfato y tacto) y que crean el sabor desde las diferentes experiencias sensoriales que determinan las preferencias de consumo. Las nuevas políticas de nutrición públicas empiezan a aplicar los descubrimientos en neurogastronomía, mejorando así el atractivo de los alimentos y la percepción de placer en los alimentos saludables menos deseados; gracias a los conocimientos de la nueva disciplina sobre el control de los factores inconscientes que rodean la experiencia al comer. Así pues, se están abriendo líneas de investigación en este camino para lograr frenar las enfermedades por la mala alimentación o disminuir el tiempo de recuperación de estas enfermedades y convertirlo en un hito obligado en el mundo de la nutrición y la salud. In recent decades, there has been a worldwide increase in chronic malnutrition. Governments and public institutions are looking for solutions to change the habits of the population towards healthy eating behaviors with the help of scientists and researchers. From this need is born a new discipline known as neurogastronomy. This work is a bibliographic review to present what this science is and its application. The results show that the rewiewed research has the involvement of several professionals with different knowledges and sensibilities (neurologists, psychologists, anthropologists, sociologists, cooks, nutritionists and dietitians, nutritionists...) who shed light on the factors (unconscious) that have a significant effect on eating behavior and health. The brain combines information about the food properties and the environment, which come from all senses (taste, sight, hearing, smell and touch) and create the taste from the different sensory experiences that determine the consumer preferences. New public nutrition policies are beginning to implement discoveries in neurogastronomy, improving the attractiveness of food and the perception of pleasure in less-desired healthy foods; thanks to the control of the unconscious factors that surround the food experience. Therefore, researches lines are being opened in this direction to reduce malnutrition or reduce the recovery time of these diseases, making this a must in the world of nutrition and health.

Treball fi de màster de l’especialitat de Llengua i Literatura Catalana i Castellana. Màster de Formació del professorat d'Educació Secundària i Batxillerat UPF-UOC Coordinador del Màster: Daniel Cassany Tutora: Lourdes Piñeiro El present treball investiga i analitza el projecte de la franja horària diària de lectura autònoma, integrada dins el programa L’impuls de la lectura del Departament d’Educació de la Generalitat de Catalunya, i els seu efectes en el desenvolupament de l`hàbit lector. Alhora, estudia la implementació de la iniciativa a un centre educatiu de secundària, a partir de la contextualització, l’observació crítica durant el període de pràcticum i la diagnosi de l’alumnat. Mitjançant la valoració de la viabilitat i efectivitat, i les capacitats i mancances de la implementació de la iniciativa, s’esbossarà una escarida proposta de millora, transcendental per a focalitzar sobre aspectes concrets a l’hora de millorar l’hàbit lector i el gust per la lectura de l’alumnat de secundària. L’anàlisi pràctica es fonamenta en un treball documental exposat al marc teòric en què es desenvolupa la correlació entre l’adquisició de l’hàbit lector i la millora dels resultats acadèmics, la importància de la lectura en el desenvolupament cognitiu de l’alumnat i en l’adquisició d’habilitats comunicatives, socials i personals, i la significació de la implicació (l’actitud, els interessos i les pràctiques) en l’adquisició de l’hàbit lector. The following work aims at investigating and analysing the project of the daily time slot of autonomous reading, integrated within the program L’impuls de la lectura -in English, The impulse of reading- of the Department of Education of the Government of Catalonia, and its effects on the development of the reading habit. At the same time, the work intents to study the implementation of hence initiative in a high school education center, through a contextualization; a critical observation during the practicum period, and a diagnosis of the alumni. Through the assessment of the program’s viability and effectiveness, as well as the capabilities and shortcomings of its implementation, a brief proposal for improvement will be outlined; which is going to be of transcendental relevance in order to be able to focus on specific aspects when it comes to improve the reading habit and the taste for reading within high school students. The case study analysis is grounded on a critical review of the relevant literature developed in the theoretical framework, and it aims at unfolding the correlation between the acquisition of the reading habit and the improvement of the students’ academic results; the importance of reading within the cognitive development of the alumni and the acquisition of communicative, social and personal abilities, as well as in the significance of involvement (the attitude, interests and practices) regarding the acquisition of the reading habit.

Applications such as load alleviation involve a wide range of parameters including a multitude of different Mach numbers, angles of attack and load cases and therefore create the demand for rapid prediction of unsteady air loads. First, there is a need for an enhanced prediction accuracy including viscous effects and shocks for a more reliable judgement of aerodynamic behavior compared to the classically-used methods based on the potential theory for such applications. Secondly, short turnaround times must be guaranteed, and this in turn means to find a suitable replacement of the tedious and time-consuming un- steady Navier-Stokes solvers. Driven by these requirements for accurate and fast prediction of air loads, a time-linearized unsteady Navier-Stokes method was developed also known as linear frequency domain method (LFD). The LFD in the DLRs TAU suite is based on the modeling of a damped harmonic oscillator, and it has been shown to be accurate and efficient for the evaluation of unsteady air loads at transonic and partly separated flow conditions [1]. Since then, the LFD method has been continuously extended and applied for various applications. The scope of target applications of the LFD has been growing consistently including different topics in aeroelasticity, where the determined surface pressure and surface skin friction distributions make an important contribution. Moreover, the time-linearized method can also be used for the efficient evaluation of flight dynamic (flight mechanical) characteristics relevant for the stability and control behavior of an aircraft. Furthermore, gust loads were successfully predicted which are important for structural and control surface design [2, 3] as well as control system performance. A recent and demanding application was the extension of the LFD method for fluidic actuators. Thus, the LFD was adopted for simulating pulsating blowing to avoid the enormously long transient phase inherently occurring during time-marching Navier-Stokes simulations. Several applications involving industrial relevant configurations are presented and discussed to outline the maturity of the method and to demonstrate the versatility of the technique.

A strong mesoscale convective system affected northeastern Italy on August 8, 2008. Notable damage and two casualties resulted, mainly due to the strong wind gusts. The event is analysed using observations, including surface data from a meso-network of meteorological stations, radar reflectivity and velocity data from a C-band Doppler radar, polar satellite images, lightning measurements from a lightning detection network and the ambient thermodynamic conditions derived from local radiosoundings. The role of the cold front is investigated; in particular, the associated strong wind descending from the Alps, which interacted with the preexisting convection in the plain, is analysed to understand the way it affected the storm development. A simple density current model is applied to describe the flow characteristics and to identify the mechanisms that could support the development of such a high wind speed. Lastly, observed wind speeds are compared with the theoretical estimates from the proposed model. The results show that different factors contribute to the very strong wind gusts registered by surface stations. The main contributor to the windstorm is a density current (a) driven by the cold front, (b) maintained by the interaction between the cold air impinging on the Friuli Venezia Giulia plain from the north and the strong regional density gradient and (c) eventually enhanced by the storm cold pool. This study highlights the complex evolution of severe storms in a region on the lee side of the Alpine chain, and emphasizes the role of the orography in the enhancement of storm.

International audience; In the context of random environment, time-domain simulation of structural responses is often necessary when the structure is nonlinear, but not only: when the structure is linear and the excitation modelled as a non-stationnary non-Gaussian process, Monte Carlo approaches are necessary to identify the probabilistic distribution of the output. In this paper we use a stochastic model developped for non-stationnary and non- Gaussian random processes. It is based on an empirical Karhunen-Loeve expansion of the process constructed from an available data basis. We study the particular case of linear structures: the Monte Carlo becomes particularely simple: one needs only to consider the construction of a low number of responses, corresponding to the deterministic eigen functions of the Karhunen-Loeve expansion, hence avoiding high number of calls to industrial codes. The KL expansion of the response is then obtained directly using these responses and the system output probabilistic characterization can be constructed through Monte Carlo simulation of the KL output model. This approach is usedin order to quantify the effect of gusts on a future airship using a database obtained during a winter storm from which a model of vertical gusts is constructed. Response comparisons for realistic and gusts and the one prescribed by national regulation requirements will be shown.; Afin de caractériser la réponse d'un dirigeable aux rafales réelles, on construit dans un premier temps un modèle probabiliste de ces rafales basé sur un développement de Karhunen Loève construit à partir d'une base de donnée du vent.Puis en utilisant la linéarité du code aérodynamique utilisé pour calculer la réponse à la rafale on identifie le modèle probabiliste de la sortie, par exemple le facteur de charge. Ce modèle probabiliste est en fait le développement de Karhunen Loève de la sortie, qui peut alors être utilisé pour générer des simulations additionnelles ouvrant la voie à une approche de Monte Carlo permettant de la caractériser.

Noblesa obliga. L'art de la casa a Barcelona (1730-1760) analitza l'univers simbòlic, particular i únic de determinats llinatges i families de la Barcelona de mitjan segle XVIII, prenent com a referent la configuració interna de la casa i l'àmbit domèstic. Através d'una mirada àmplia i polièdrica, l'autora ens ensenya l'agençament i la distribució de la llar, entenent-la com un ens viu en la qual hi tenen cabuda des dels ritus de passatge - néixer, casar-se, entrar al convent, morir, etc. - fins als actes més quotidians dels àpats, la diversió o "el rebre". El resultat és un retaule esplèndid de la vida, del gust i de la moda d'un estament social que es deixa copsar i comprendre a través del seu espai més íntim.

[No Abstract]

A recent consideration in aircraft design is the use of folding wing-tips with the aim of enabling higher aspect ratio aircraft with less induced drag while also meeting airport gate limitations. This study investigates the effect of exploiting folding wing-tips in flight as a device to reduce both static and dynamic loads. A representative civil jet aircraft aeroelastic model was used to explore the effect of introducing a wing-tip device, connected to the wings with an elastic hinge, on the load behaviour. For the dynamic cases, vertical discrete gusts and continuous turbulence were considered. The effects of hinge orientation, stiffness, damping and wing-tip weight on the static and dynamic response were investigated. It was found that significant reductions in both the static and dynamic loads were possible. For the case considered, a 25% increase in span using folding wing-tips resulted in almost no increase in loads.

Wind gusts can have destructive effects on many structures and objects deemed valuable to humans. The aviation industry, for example, views gusts as a major hazard. Their destructive effect is proportional to the momentum that a specific gust imposes onto an object. The actual definition of a gust has a strong influence on how its impact can be quantified. Existing gust definitions, however, are largely based on fixed parameters describing shape requirements and thresholds and are often developed only for specific use cases. These gust definitions do not provide a direct link to the physical impact a particular gust has on a structure or object. The overall goal of this study is to provide such a direct link. The application of a wavelet-analysis to a turbulence-resolving wind velocity signal allows for the localization of signal amplitudes in the period as well as in the time domain. In this paper, we use wavelet-analysis in order to develop a straight-forward method of deriving information about gusts from a wind velocity signal. In order to define what a particular gust might be, we suggest the specification of a characteristic period and amplitude in the time-domain. We define a generic gust as a section of a wind velocity signal, where the wavelet-analysis detects that characteristic amplitude to be matched or exceeded within that characteristic period. The characteristic amplitudes and periods are generic and span a two-dimensional space of generic gust definitions. The method can be applied to turbulence resolving simulation data as well as high-resolution wind velocity measurement data. It can detect gusts of any shape, it is unbiased regarding any specific use case and invariant to changes of the mean wind. We provide a detailed description of the method, its capabilities and demonstrate its application to high resolution wind velocity measurement data.

Diese Dissertation beschäftigt sich mit der Entwicklung und dem Test eines Empfängerprototyps für die einachsige Messung von Windgeschwindigkeiten in der Atmosphäre. Ein Lidarsensor auf Basis dieses Prototyps soll langfristig die Vision einer automatischen Ausregelung von Turbulenzen, Böen und Wirbelschleppen ermöglichen und so auf allen Flughöhen den Komfort verbessern, Unfällen vorbeugen, und zur Gewichtsreduktion im Flugzeugbau beitragen. Hierfür werden zunächst unterschiedliche direkte Doppler-WindLidar (DWL) Empfängerkonzepte hinsichtlich der Sensoranforderungen dieser Anwendung theoretisch verglichen. Kriterien sind die Leistungsfähigkeit als spektraler Analysator, ihre Entfernungsauflösung, die Messbarkeit bei geringen Aersosolkonzentrationen, sowie der Uberlapp in Nahdistanz, und ihre Komplexität. Auf Basis dieser Kriterien wird ein streifenabbildendes Verfahren beruhend auf einem Michelson-Interferometer ausgewählt, welches eine Kompensation der im Nahfeld auftretenden Winkelverteilungen ermöglicht. Der Uberlapp in Nahdistanz (50 bis 300 m) und die Kombination mit einem schnellen Zeilendetektor erlauben die Messung an mehreren longitudinalen Messpunkten quasi gleichzeitig, und ohne Kenntnis des Partikelrückstreuverhöltnisses. Das Konzept wird durch Berechnungen und End-to-end Simulationen evaluiert. Ein fasergekoppelter Aufbau wird konzipiert. Der Empfängerprototyp wird dann realisiert und charakterisiert. Ein monolithisches Michelson Interferometer soll thermomechanische Stabilität gewährleisten und wird hinsichtlich optimaler Leistungsfähigkeit spezifiziert und von einem Zulieferer gebaut. Das Interferometer wird dann in Bezug auf Streifenkontrast und Streifenform charakterisiert. Berechnungen und optische Simulationen zur Beleuchtung des Interferometers mit einer Multimodefaser und der Abbildung des linearen Interferenzstreifen auf ein Photomultipliertubearray werden durchgeführt und der Empfänger wird aufgebaut. Zu diesem Zweck werden Verstärkerelektroniken entwickelt, gebaut, und mit Analog-Digital-Wandler Karten kombiniert. Eine Multimodefaser wird in einer Kombination aus Experimenten und Simulationen hinsichtlich ihrer Scramblingeigenschaften zum Zweck der Biasreduktion und in Bezug auf Speckleeigenschaften zum Zweck der Specklerauschunterdrückung untersucht. Für Validierungsmessungen wird ein Auswertealgorithmus der Interferenzstreifen entwickelt, welcher eine Korrektur der Beleuchtung des Interferometers beinhaltet. Für die Bestimmung der Streifenposition wird ein Downhill-Simplex-Algorithmus verwendet. Im Januar 2018 wurden mit dem aufgebaute Empänger bodengestützten einachsige Windgeschwindigkeitsmessungen durchgeführt und mit Referenzmessungen eines kohärenten DWL (Windcube 200S, Leosphere) verglichen. Es zeigt sich, dass die Horizontalmessungen beider Lidarsysteme eine hohe Korrelation von bis zu 0.89 aufweisen und dass der Prototyp Messungen mit einer Auflösung von 30 m in Entfernungen von 50 m und 76 m erlaubt. Allerdings zeigt sich auch ein entfernungsabhängiger systematischer Fehler von einigen m/s, dessen Zeitabhängigkeit durch eine Anderung der Beleuchtung hervorgerufen wird, und der korrigiert werden muss. Nach der Korrektur ist die relative Präzision beider Lidarsysteme um die 0.7 m/s für den Fall dass jeweils über ein halbe Sekunde gemittelt wird. Weitere vertikal orientierte Windgeschwindigkeitsmessungen im März 2018 erlauben langreichweitige (bis 900 m), entfernungsaufgelöste Messungen mit dem Empfängerprototyp. Ein Vergleich mit den Anforderungen für das Aussteuern von Wirbelschleppen mit einer erforderlichen Messrate von mehr als 45 Hz bei gleichzeitiger Messunsicherheit kleiner 1 m/s ergibt dass der Empfänger diesen Anforderungen noch nicht entsprechen kann. In Zukunft sind Verbesserungen der Effizienz des Empfängers, der Temperaturstabilisierung, sowie der Beleuchtungsfunktionskorrekturroutine erforderlich., This thesis describes the development and test of a lidar receiver prototype for the uniaxial measurement of wind speeds in the atmosphere. An airborne lidar sensor based on this prototype may in the long run facilitate the vision of a feed-forward control of turbulence, gusts and wake vortices, in order to enhance comfort, prevent accidents, and reduce the weight of future aircraft constructions. For this purpose, different direct-detection Doppler Wind Lidar (DWL) receiver concepts are compared theoretically with respect to the sensor requirements of this application, i.e. with respect to the performance as spectral analyzer, range-resolution, measurement capability with low aerosol concentrations, overlap in the near-range (50 m to 300 m), and complexity. With respect to these criteria, a fringeimaging Michelson interferometer is selected, which enables compensation of the angular distributions in the near-range. Full overlap in the near-range combined with a fast linear array detector permit wind speed measurements at multiple longitudinal measurment points quasi-simultaneously and without knowing the particle backscattering ratio. The concept is evaluated by calculations and end-to-end simulations. A fiber-coupled setup is conceptualized. The receiver prototype is then realized and characterized. A monolithic Michelson interferometer is to provide thermo-mechanical stability, and is specified according to optimal performance, and is built by an industrial supplier. The interferometer is then characterized with respect to interference fringe contrast and shape. Calculations and optical simulations of the multimode fiber-coupled illumination of the interferometer and of the imaging of the linear fringe on a photomultiplier tube array are carried through and the receiver is built up. For this purpose, amplifier electronics are designed, built, and combined with analog-to-digital converter cards. A frequency-tripled Nd:YAG laser is applied as transmitter. A multimode fiber is characterized in a combination of experiments and simulations with regard to its scrambling properties for reducing biases and with regard to its speckle properties for reducing speckle noise. For validation measurements a retrieval algorithm is developed, which entails a correction of the illumination of the interferometer. A fitting routine based on a Downhill-Simplex-Algorithm is applied for determining the shift of the interference fringes, yielding the Doppler frequency shift and the line-of-sight component of the wind speed. In late January 2018, ground-based, uniaxial wind speed measurements with the receiver prototype were carried out and are compared to referential measurements with a coherent DWL (Windcube 200S, Leosphere). It shows that horizontal measurements of both lidar systems yield a high correlation of up to 0.89 and that the prototype allows for wind speed measurements with a measurements resolution of 30 m at distances of 50 m and 76 m. However it shows as well that a range-dependent systematic error of several m/s exists, which has to be corrected. Its time-dependence is evoked by a long-term change of the illumination. After correction the relative precision of both lidar systems is around 0.7 m/s in case of respective averaging times of 0.5 s. Further vertically oriented wind speed measurements in March 2018 reveal that long-range (up to 900 m), range-resolved measurements can be done with the receiver prototype. A comparison with the requirements for the feed-forward control of wake vortices (i.e., a measurement update rate above 45 Hz and at the same time a measurement uncertainty of < 1 m/s) yields that the receiver prototype does not currently meet those requirements. In the future, improvements of the efficiency, of the temperature stabilization, and of the illumination function correction routine are necessary.

Pòster Juny

In order to allow for a more economic and environmentally friendly aircraft operation and to fulfill the greener imperative demanded by today's society, fuel savings and cost reduction play a key role in the development of modern aircraft. Besides the efficiency of engines and aerodynamics, the aircraft weight has a major impact on fuel consumption. Reducing structural wing loads caused by atmospheric disturbances (such as gusts, turbulence and wake vortices) thereby became a main research interest of today's aircraft industry. Reducing such loads will allow the aircraft manufacturer building and certifying aircraft to smaller load envelopes, inherently reducing the airframe structural weight and thus reduce fuel, emissions and cost. In this contribution we discuss latest research and development trends in the field of modelling and control for load alleviation on modern, fly-by-wire aircraft. Covering a broad range of relevant topics, the paper is divided into four main subtopics as follows: (i) For analyzing loads on the aircraft in an early design stage with high fidelity simulation techniques, detailed models of the structure and the aerodynamics are generated. Here, we discuss the latest developments on how these complex aeroelastic models (generated by CFD methods, e.g.) are derived and can be approximated by lower order models for facilitating the subsequent controller design. (ii) Directly linked to the modelling in (i) is the feedback control design task. The use of available local measurements as well as virtual sensors for incoming gusts provides a profound basis for alleviating the associated structural loads. This subsection discusses the current trends in control development such as estimator design and robust control techniques to feed back the gust estimates. (iii) Also, in direct link to the modelling (i) but also to the lidar sensors (iv) feedforward control allows for an enhanced load alleviation performance than a pure feedback due to its anticipative behavior (control actions can be taken earlier). In contrast to the feedback approaches (ii), it requires additional forward sensing capabilities, such as lidar for the gust anticipation. Detailed models of these sensors are needed to allow for a dedicated feedforward control design: these lidar sensor models are investigated in great depth within a dedicated activity (iv) and in surrogate models – derived from them – are considered in the feedforward design tool. In this subtopic the surrogate models of the lidar sensors, the wind reconstruction algorithms as well as the feedforward load alleviation design workflow are presented. (iv) The feedforward control approaches in (iii) require measurements of the incoming gust, which shall be provided by advanced lidar measurement systems. The latest development directions for adapting the lidar technology to fulfil the needs of feedforward gust load alleviation applications are discussed in this subtopic. These progresses represent a key enabling technology for viable anticipation of incoming gusts and winds, paving the way for improving the gust load alleviation capabilities for future aircraft generations.

Recent developments of the gust simulation facility for the ARA Transonic Wind Tunnel along with verification and demonstration experiments are described. The facility was first reported in the open literature in 2015, when a test to prove the concept of gust production at transonic speeds through directed trailing-edge blowing from gust vanes positioned in the tunnel contraction was detailed. The electro-mechanical improvements to the gust vanes over the past two years are reviewed, including the enhancements to the blowing control system to allow gusts of uniform amplitude to be produced over a floor-mounted civil aircraft half-model. Experiments both to verify the improved control system and to demonstrate the impact of gusts on a half-model furnished with advanced optical diagnostics to measure the dynamic behaviour are discussed. It is concluded that the capability for transonic testing using the gust rig is maturing, but some improvements are still required before this unique facility can be considered fully industrialised.

A tremendous number of gust load cases needs to be computed during the aircraft design and certification process. From an aerodynamic point of view, gust loads predictions in industry rely on linear potential flow methods which are inappropriate at transonic flight conditions. Prediction accuracy can be enhanced by accounting for aerodynamic loads computed with computational fluid dynamics, eventually resulting in lighter, more efficient designs. However, full order, unsteady time-marching simulations are still prohibitively expensive in an industrial environment. Therefore, different reduced order modelling techniques have been propose to decrease computational cost in many query scenarios while retaining the underlying physics and a high level of accuracy. This paper focuses on an unsteady nonlinear reduced order model based on least squares residual minimization and a comparison to the linearized frequency domain method. While the latter is in line with current industrial practice of sampling aerodynamic forces in the frequency domain, it neglects dynamic nonlinearities which are included in the former approach. Results are presented for an airfoil at transonic flow conditions exhibiting shock induced Separation during the airfoil-gust interaction and for the NASA common research model at cruise flight conditions. Essential quantities for the gust loads analysis, such as global coefficients and sectional forces, are evaluated and compared to highlight strengths and weaknesses of both model reduction techniques. Moreover, distributed surface loads, which can be used for a direct sizing of the structural model, are analyzed. Computational cost, split in an offline and an online part, is quantified to demonstrate efficiency gains compared to full-order solutions.

URL:http://sujest.selcuk.edu.tr/sumbtd/article/view/554 DOI: 10.15317/Scitech.2018.136, Bu çalışmada İstanbul'da bulunan 10 meteoroloji istasyonunun 1970 ile 2016 yılları arasında meydana gelen fırtınaları araştırılmıştır. 47 yıllık periyodda 301 gün, fırtınalı gün olarak tespit edilmiştir. Mevsimsel olarak değerlendirdiğimizde fırtınaların % 60.1 Kış, % 12.6 İlkbahar, % 4.0 Yaz ve % 23.3 Sonbahar mevsimlerinde meydana gelmiştir. 47 yıllık periyodda yıllık ortalama fırtınalı gün sayısı 6.4 ve hamle değeri en yüksek 32.9 m/s rüzgar şiddetiyle Şile Meteoroloji İstasyonu'nda ölçülmüştür. Fırtına sayısı ve şiddetinde azalan yönde lineer trend bulunmaktadır, In this study, the storms between 1970 and 2016 the 10 meteorological stations in Istanbul were investigated. It has been determined 301 days in 47 years period as stormy days. When we evaluated seasonally, 60.1% of the storms occured in winter, 12.6% in spring, 4.0% in summer and 23.3% in autumn. The average number of stormy days is 6.4 per year for a 47 year period. The value of the gust wind measured with a maximum wind speed of 32.9 m/s was at the Şile Meteorology Station. There is a linear decreasing trend in the number of stormy days and intensity of the storms within the study period.

Studying isolated gust effects on simple airfoil models in a controlled environment is a necessity to further the development of MAV gust response and control laws. This work describes the creation of a vertical gust generator in a low speed, low turbulence wind tunnel through the use of an actuated fan placed below the tunnel and ducted through its floor. Gusts of up to 40% of the freestream velocity were created. Characterization of the gust generator is shown, and its interaction with a stationary wing at several angles of attack is evaluated. The actuated gust profile is also compared to that of a pitched wing in a gust-less environment with many visible similarities.

El gust és un dels cinc sentits que ens permeten obtenir informació de l'exterior. Es diu que resideix a la llengua, però en realitat és el cervell qui l'interpreta. La llengua actua únicament d'antena receptora. Tanmateix, com han demostrat diversos estudis, la percepció del gust és molt més àmplia, i inclou la integració sensorial no únicament de les terminacions nervioses de la llengua, sinó també de l'olfacte, l'oïda, la vista i fins i tot el tacte. El sabor dels aliments, tal com l'interpreta el cervell, també depèn de l'aspecte del menjar que ingerim, del soroll que fa quan el masteguem i del tacte que té. Unes qualitats que els cuiners innovadors han utilitzat de manera magistral en les seves creacions, les quals al seu torn han servit perquè els investigadors comprenguem millor el funcionament integrat del cervell. Fins i tot han permès desenvolupar una nova branca del coneixement, la neurogastronomia.

En aquest estudi s’investigarà quins sentits intervenen quan es tasten diferents productes alimentaris, (pa de motlle, cervesa, bombons, patates de bossa, iogurts, batuts de xocolata, quètxup i refrescos de cola) sense saber-ne la marca i veurem si, un cop desvelada la marca, el consumidor canvia d’opinió respecte a la que tenia en un principi. Aquest estudi es complementarà amb les opinions dels 12 participants en el tast i, aquestes, es compararan amb la publicitat de cada marca. En darrer terme, s’ha analitzat si les marques reflecteixen i potencien les opinions dels seus consumidors en la seva publicitat per diferenciar-se dels seus competidors. Està clar que els sentits juguen un paper essencial en el consum de qualsevol producte, però no totes les marques en potencien el seu ús en la publicitat. Diferents estudis ja realitzats, mostren que els sentits desencadenen un comportament de compra i, tot i no ser els únics que ho aconsegueixen, són un element essencial. La clau per aconseguir-ho és combinar diferents sentits per crear un vincle emocional amb el consumidor i així atraure’l per a que consumeixi la marca. En aquest projecte també es revelaran els altres factors, a banda dels sentits, que intervenen durant el tast dels productes alimentaris.