Recursos de colección

Archivo Digital UPM (109.118 recursos)

This is an institutional repository providing access to the research output of the institution. Primarily contains thesis.

Materia = Aeronáutica

Mostrando recursos 1 - 20 de 727

  1. PIC computation of electron current collection to a moving bare tether in the mesothermal condition

    Onishi, Tatsuo; Martínez-Sánchez, Manuel; Cooke, David L.; Sanmartín Losada, Juan Ramón
    In tethered satellite technology, it is important to estimate how many electrons a spacecraft can collect from its ambient plasma by a bare electrodynamic tether. The analysis is however very difficult because of the small but significant Geo-magnetic field and the spacecraft’s relative motion to both ions and electrons. The object of our work is the development of a numerical method, for this purpose. Particle-In-Cell (PIC) method, for the calculation of electron current to a positive bare tether moving at orbital velocity in the ionosphere, i.e. in a flowing magnetized plasma under Maxwellian collisionless conditions. In a PIC code, a...

  2. A review of electrodynamic tethers for space applications

    Sanmartín Losada, Juan Ramón; Lorenzini, Enrico C.; Martínez Sánchez, Manuel
    Space applications of electrodynamic tethers, and basic issues and constraints on their operation are reviewed. The status of the bare-tether solution to the problem of effective electron collection from a rarefied magnetized plasma is revisited. Basic modes of tether operation are analyzed; design parameters and parametric domains where a bare electrodynamic tether is most efficient in deorbiting, rebooking, or power generation, are determined. Use of bare tethers for Radiation Belt Remediation and generation of electron beams for ionospheric research is considered. Teiher heating, arcing, and bowing or breaking, as well deployment strategies are discussed.

  3. Laminar-turbulent transition induced by a discrete roughness element in a supersonic boundary layer

    De Tullio, N.; Paredes Gonzalez, Pedro; Sandham, N. D.; Theofilis, Vassilios
    The linear instability and breakdown to turbulence induced by an isolated roughness element in a boundary layer at Mach 2:5, over an isothermal flat plate with laminar adiabatic wall temperature, have been analysed by means of direct numerical simulations, aided by spatial BiGlobal and three-dimensional parabolized (PSE-3D) stability analyses. It is important to understand transition in this flow regime since the process can be slower than in incompressible flow and is crucial to prediction of local heat loads on next-generation flight vehicles. The results show that the roughness element, with a height of the order of the boundary layer displacement thickness, generates...

  4. On the simulation of the UPMSAT-2 microsatellite power

    Manuel Navío, Carlos de; Cubas Cano, Javier; Pindado Carrion, Santiago
    Simulation of satellite subsystems behaviour is extramely important in the design at early stages. The subsystems are normally simulated in the both ways : isolated and as part of more complex simulation that takes into account imputs from other subsystems (concurrent design). In the present work, a simple concurrent simulation of the power subsystem of a microsatellite, UPMSat-2, is described. The aim of the work is to obtain the performance profile of the system (battery charging level, power consumption by the payloads, power supply from solar panels....). Different situations such as battery critical low or high level, effects of high current charging...

  5. Computation of nonlinear streaky structures in boundary layer flow

    MartÍn Bautista, Juan A.; Martel Escobar, Carlos
    In this work, the Reduced Navier Stokes (RNS) are numerically integrated, and used to calculate nonlinear finite amplitude streaks. These structures are interesting since they can have a stabilizing effect and delay the transition to the turbulent regime. RNS formulation is also used to compute the family of nonlinear intrinsic streaks that emerge from the leading edge in absence of any external perturbation. Finally, this formulation is generalized to include the possibility of having a curved bottom wall

  6. Software tool for simulation of aircraft trajectories

    Crespo Moreno, Javier; Alonso Alarcon, Jose Felix; López Morales, Andres; Arnaldo Valdes, Rosa Maria
    New concepts in air navigation have been introduced recently. Among others, are the concepts of trajectory optimization, 4D trajectories, RBT (Reference Business Trajectory), TBO (trajectory based operations), CDA (Continuous Descent Approach) and ACDA (Advanced CDA), conflict resolution, arrival time (AMAN), introduction of new aircraft (UAVs, UASs) in air space, etc. Although some of these concepts are new, the future Air Traffic Management will maintain the four ATM key performance areas such as Safety, Capacity, Efficiency, and Environmental impact. So much, the performance of the ATM system is directly related to the accuracy with which the future evolution of the traffic...

  7. Molecular Dynamics Simulations of Couette flow

    Martín Bautista, Juan A.; Meneghini, Julio; Theofilis, Vassilios
    The first steps towards developing a continuum-molecular coupled simulations techniques are presented, for the purpose of computing macroscopic systems of confined fluids. The idea is to compute the interface wall-fluid by Molecular Dynamics simulations, where Lennard-Jones potential (and others) have been employed for the molecular interactions, so the usual non slip boundary condition is not specified. Instead, a shear rate can be imposed at the wall, which allows to obtain the properties of the wall material by means of an iterative method. The remaining fluid region will be computed by a spectral hp method. We present MD simulations of a...

  8. Reducción de Costes con la Implementación de la Gestión del Ciclo de Vida en un Fabricante de Aerogeneradores

    Calvo Narvaez, Felix; Rodríguez Monroy, Carlos
    El propósito de este artículo es desarrollar sobre una aplicación genérica PLM (Product Lifecycle Management), una solución que ayudará a las empresas proveedoras de servicios de ingeniería y fabricación del sector aeronáutico y renovables, a superar nuevos retos. En estos sectores los fabricantes de primer nivel (OEM?s) tienden a subcontratar el desarrollo y la fabricación de componentes a proveedores mediante paquetes de trabajo, como en el caso de los aerogeneradores. La gestión de dichos paquetes por los proveedores puede optimizarse mediante la implantación de una solución PLM. Esta herramienta es clave para garantizar el cumplimiento de los requerimientos del fabricante,...

  9. Analysis of Renewable Energy Policies Related to Repowering the Wind Energy Sector: the Spanish Case

    Rodriguez, Roberto; Rodríguez Monroy, Carlos; Rodriguez, Rubén; Calvo Narvaez, Felix
    In countries that started early with wind energy, the old wind turbines were located in places where the wind is often very good. Since the best places in which the wind is concerned are occupied by old wind turbines (with lower capacity than the more recent ones) the trend is to start replacing old turbines with new ones. With repowering, the first generation of wind turbines can be replaced by modern multi-megawatt wind turbines. The aim of this article is to analyze energy policies in the Spanish energy sector in the repowering of wind farms from the viewpoint of the...

  10. Explicit expressions for solar panel equivalent circuit parameters based on analytical formulation and the Lambert W - Function

    Cubas Cano, Javier; Pindado Carrion, Santiago; Manuel Navío, Carlos de
    Due to the high dependence of photovoltaic energy efficiency on environmental conditions (temperature, irradiation...), it is quite important to perform some analysis focusing on the characteristics of photovoltaic devices in order to optimize energy production, even for small-scale users. The use of equivalent circuits is the preferred option to analyze solar cells/panels performance. However, the aforementioned small-scale users rarely have the equipment or expertise to perform large testing/calculation campaigns, the only information available for them being the manufacturer datasheet. The solution to this problem is the development of new and simple methods to define equivalent circuits able to reproduce the...

  11. On the analytical approach for modeling photovoltaic systems behavior

    Cubas Cano, Javier; Pindado Carrion, Santiago; Victoria Pérez, Marta
    The 1-diode/2-resistors electric circuit equivalent to a photovoltaic system is analyzed. The equations at particular points of the I–V curve are studied considering the maximum number of terms. The maximum power point as a boundary condition is given special attention. A new analytical method is developed based on a reduced amount of information, consisting in the normal manufacturer data. Results indicate that this new method is faster than numerical methods and has similar (or better) accuracy than other existing methods, numerical or analytical.

  12. Some developments on cup anemometer aerodynamics

    Pindado Carrion, Santiago; Cubas Cano, Javier
    In the present study the geometry of cups is experimentally studied through anemometer performance. This performance is analyzed in two different ways. On the one hand the anemometer transfer function between cases is compared. On the other hand the stationary rotation speed is decomposed into constant and harmonic terms, the comparison being established between the last ones. Results indicate that some cup shapes can improve the uniformity of anemometer rotation, this fact being important to reduce degradation due to ageing.

  13. Fourier analysis of the aerodynamic behavior of cup anemometers

    Pindado Carrion, Santiago; Pérez Sarasola, Imanol; Aguado Roca, Maite
    The calibration results (the transfer function) of an anemometer equipped with several cup rotors were analyzed and correlated with the aerodynamic forces measured on the isolated cups in a wind tunnel. The correlation was based on a Fourier analysis of the normal-to-the-cup aerodynamic force. Three different cup shapes were studied: typical conical cups, elliptical cups and porous cups (conical-truncated shape). Results indicated a good correlation between the anemometer factor, K, and the ratio between the first two coefficients in the Fourier series decomposition of the normal-to-the-cup aerodynamic force

  14. Extracting energy from Vortex-Induced Vibrations: A parametric study

    Barrero-Gil, Antonio; Pindado Carrion, Santiago; Avila Sanchez, Sergio
    Here, Vortex-Induced Vibrations (VIVs) of a circular cylinder are analyzed as a potential source for energy harvesting. To this end, VIV is described by a one-degree-of-freedom model where fluid forces are introduced from experimental data from forced vibration tests. The influence of some influencing parameters, like the mass ratio m∗ or the mechanical damping ζ in the energy conversion factor is investigated. The analysis reveals that: (i) the maximum efficiency ηM is principally influenced by the mass-damping parameter m∗ζ and there is an optimum value of m∗ζ where ηM presents a maximum; (ii) the range of reduced velocities with significant...

  15. Analysis of calibration results from cup and propeller anemometers. Influence on wind turbine Annual Energy Production (AEP) calculations

    Pindado Carrion, Santiago; Vega, Enrique; Martínez, Alejandro; Meseguer, Encarnación; Franchini, Sebastián; Pérez Sarasola, Imanol
    The calibration coefficients of several models of cup and propeller anemometers were analysed. The analysis was based on a series of laboratory calibrations between January 2003 and August 2007. Mean and standard deviation values of calibration coefficients from the anemometers studied were included. Two calibration procedures were used and compared. In the first, recommended by the Measuring network of Wind Energy Institutes (MEASNET), 13 measurement points were taken over a wind speed range of 4 to 16  m  s−1. In the second procedure, 9 measurement points were taken over a wider speed range of 4 to 23  m  s−1. Results indicated no significant differences...

  16. An agent-based approach for the design of the future european air traffic management system

    Molina, Martin; Martín Cristobal, Jorge; Carrasco Herranz, Sergio
    This paper describes an agent-based approach for the simulation of air traffic management (ATM) in Europe that was designed to help analyze proposals for future ATM systems. This approach is able to represent new collaborative deci-sion processes for flow traffic management, it uses an intermediate level of ab-straction (useful for simulations at larger scales), and was designed to be a practi-cal tool (open and reusable) for the development of different ATM studies. It was successfully applied in three studies related to the design of future ATM systems in Europe.

  17. Agent-based modeling and simulation for the design of the future european Air Traffic Management system: the experience of CASSIOPEIA

    Molina, Martin; Carrasco, Sergio; Martín Cristobal, Jorge
    The SESAR (Single European Sky ATM Research) program is an ambitious re-search and development initiative to design the future European air traffic man-agement (ATM) system. The study of the behavior of ATM systems using agent-based modeling and simulation tools can help the development of new methods to improve their performance. This paper presents an overview of existing agent-based approaches in air transportation (paying special attention to the challenges that exist for the design of future ATM systems) and, subsequently, describes a new agent-based approach that we proposed in the CASSIOPEIA project, which was developed according to the goals of the...

  18. Aerodynamic Analysis of Cup Anemometers Performance: The Stationary Harmonic Response

    Pindado Carrion, Santiago; Cubas Cano, Javier; Sanz Andres, Angel Pedro
    The effect of cup anemometer shape parameters, such as the cups’ shape, their size, and their center rotation radius, was experimentally analyzed.This analysis was based on both the calibration constants of the transfer function and the most important harmonic termof the rotor’smovement,which due to the cup anemometer design is the third one.This harmonic analysis represents a new approach to study cup anemometer performances. The results clearly showed a good correlation between the average rotational speed of the anemometer’s rotor and the mentioned third harmonic term of its movement.

  19. Motores Alternativos : Software

    Velázquez López, Ángel Gerardo; Arias Pérez, Juan Ramón
    Software del libro Motores Alternativos

  20. Efficient speed advisories for multi-stage-metering arrival management

    Bronsvoort, Jesper; McDonald, Greg; Soni, Meru; Besada Portas, Juan Alberto
    This paper presents a methodology and algorithm for Air Traffic Control (ATC) to efficiently achieve schedules arrival times through speed control in the presence of uncertainty. The methodology does not assume the availability of airborne time of arrival control and can therefore be applied to legacy aircraft. The speed advisories are calculated in a manner that allows for sufficient control margin to, if required, adjust the aircraft's trajectory at a later stage to correct for estimated arrival time drift at the lowest impact to efficiency. The methodology is therefore envisioned to prevent major last-minute interventions and instead assists ATC in...

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