Recursos de colección

Archivo Digital UPM (107.543 recursos)

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

Materia = Mécanica

Mostrando recursos 1 - 20 de 532

  1. 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

  2. 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...

  3. Design of a 3D printing capable of creating multiple objects simultaneously

    Bobo Garcia, Rafael
    Proyecto de Fin de Carrera de Ingenieria Industrial, versando sobre el completo diseño de una impresora 3D

  4. Usando Kinect como sensor para una pulverización inteligente.

    Correa Farias, Christian; Valero Ubierna, Constantino; Barreiro Elorza, Pilar; Ortiz-Cañavate Puig-Mauri, Jaime; Gil Sierra, Jacinto
    Este trabajo esta orientado a resolver el problema de la caracterización de la copa de arboles frutales para la aplicacion localizada de fitosanitarios. Esta propuesta utiliza un mapa de profundidad (Depth image) y una imagen RGB combinadas (RGB-D), proporcionados por el sensor Kinect de Microsoft, para aplicar pesticidas de forma localizada. A través del mapa de profundidad se puede estimar la densidad de la copa y a partir de esta información determinar qué boquillas se deben abrir en cada momento. Se desarrollaron algoritmos implementados en Matlab que permiten además de la adquisición de las imágenes RGB-D, aplicar plaguicidas sólo a hojas y/o frutos según...

  5. Influence of the track quality and of the properties of the wheel rail rolling contact on vehicle dynamics

    Suárez Esteban, Berta; Félez Mindán, Jesús; Lozano, J.A.; Rodríguez, Pablo
    This work describes an analytical approach to determine what degree of accuracy is required in the definition of the rail vehicle models used for dynamic simulations. This way it would be possible to know in advance how the results of simulations may be altered due to the existence of errors in the creation of rolling stock models, whilst also identifying their critical parameters. This would make it possible to maximize the time available to enhance dynamic analysis and focus efforts on factors that are strictly necessary.In particular, the parameters related both to the track quality and to the rolling contact...

  6. Assessment of the influence of the elastic properties of rail vehicle suspensions on safety, ride quality and track fatigue

    Suárez Esteban, Berta; Mera Sanchez de Pedro, Jose Manuel; Martinez Muneta, M. Luisa; Chover Álvarez-Monteserín, José Antonio
    A sensitivity analysis has been performed to assess the influence of the elastic properties of railway vehicle suspensions on the vehicle dynamic behaviour. To do this, 144 dynamic simulations were performed modifying, one at a time, the stiffness and damping coefficients, of the primary and secondary suspensions. Three values were assigned to each parameter, corresponding to the percentiles 10, 50 and 90 of a data set stored in a database of railway vehicles.After processing the results of these simulations, the analyzed parameters were sorted by increasing influence. It was also found which of these parameters could be estimated with a...

  7. Sensitivity analysis to assess the influence of the inertial properties of railway vehicle bodies on the vehicle’s dynamic behaviour

    Suárez Esteban, Berta; Félez Mindán, Jesús; Maroto Ibáñez, Joaquín; Rodríguez, Pablo
    A sensitivity analysis has been performed to assess the influence of the inertial properties of railway vehicles on their dynamic behaviour. To do this, 216 dynamic simulations were performed modifying, one at a time, the masses, moments of inertia and heights of the centre of gravity of the carbody, the bogie and the wheelset. Three values were assigned to each parameter, corresponding to the percentiles 10, 50 and 90 of a data set stored in a database of railway vehicles. After processing the results of these simulations, the analyzed parameters were sorted by increasing influence. It was also found which of...

  8. Finite elastic deformations of transversely isotropic circular cylindrical tubes

    Hamdaoui, Mustapha El; Merodio Gomez, Jose; Ogden, Ray W.; Rodríguez, Javier
    We consider the finite radially symmetric deformation of a circular cylindrical tube of a homogeneous transversely isotropic elastic material subject to axial stretch, radial deformation and torsion, supported by axial load, internal pressure and end moment. Two different directions of transverse isotropy are considered: the radial direction and an arbitrary direction in planes normal locally to the radial direction, the only directions for which the considered deformation is admissible in general. In the absence of body forces, formulas are obtained for the internal pressure, and the resultant axial load and torsional moment on the ends of the tube in respect...

  9. Claas Lexion 780 Terratrac, el relevo generacional.

    Barreiro Elorza, Pilar; Diezma Iglesias, Belen; Moya Gonzalez, Adolfo; Valero Ubierna, Constantino
    El día 25 de junio llevamos a cabo en la Puebla de Montalbán (Toledo) un ensayo de verificación de las prestaciones de una cosechadora Claas Lexion 780 Terratrac, comparándolas con las características de una máquina más antigua, una Claas Lexion 530 Montana que disponía de un cabezal McDon, empleándose además en el primer caso un sistema de auto-guiado. La profusión de datos disponibles no deja lugar a la especulación, todo, o mejor dicho, casi todo puede ser cuantificado.

  10. Ingeniería de máquinas : discurso de ingreso [en la Real Academia de Ingeniería] del Excmo. Sr. D. Jaime Domínguez Abascal y contestación del académico Excmo. Sr. D. Enrique Alarcón Álvarez

    Domínguez Abascal, Jaime; Alarcón Álvarez, Enrique
    En el discurso se reivindica el papel actual de la ingeniería mecánica como impulsora del desarrollo de las máquinas. Comienza con una breve exposición de la evolución de las máquinas a lo largo de la historia y su influencia en el desarrollo económico y social. Igualmente, señala la importancia de otras áreas de la ingeniería en el desarrollo de las máquinas actuales y el carácter multidisciplinar del diseño y desarrollo de las máquinas actuales. Ante la nueva situación, el discurso analiza el papel que desempeña actualmente la ingeniería de máquinas. Asimismo, comprueba que la aportación de otras disciplinas ha llevado...

  11. Presentación [del libro "Simulación del comportamiento óseo. Aplicación al diseño de implantes"]

    Alarcón Álvarez, Enrique
    La aplicación de los fundamentos, métodos y herramientas básicas de la Mecánica del Daño Continuo a un modelo de comportamiento biológico como es la remodelación ósea supone un mutuo enriquecimiento y las posibilidades de generalización o ampliación de las disciplinas involucradas. Así surge la idea de reparación que, termodinámicamente sería imposible en un sistema mecánico puro aislado pero que aparece como conveniente y posible en un sistema simulado como mecánico pero en realidad acoplado y, por tanto, con entradas energéticas adicionales como es la energía metabólica en este caso. El grupo que dirige el profesor Doblaré, a quien tuve la oportunidad...

  12. Order 10 4 speedup in global linear instability analysis using matrix formation

    Paredes Gonzalez, Pedro; Hermanns Navarro, Miguel; Le Clainche Martínez, Soledad; Theofilis, Vassilios
    A unified solution framework is presented for one-, two- or three-dimensional complex non-symmetric eigenvalue problems, respectively governing linear modal instability of incompressible fluid flows in rectangular domains having two, one or no homogeneous spatial directions. The solution algorithm is based on subspace iteration in which the spatial discretization matrix is formed, stored and inverted serially. Results delivered by spectral collocation based on the Chebyshev-Gauss-Lobatto (CGL) points and a suite of high-order finite-difference methods comprising the previously employed for this type of work Dispersion-Relation-Preserving (DRP) and Padé finite-difference schemes, as well as the Summationby- parts (SBP) and the new high-order finite-difference...

  13. Numerical characterization of particle dispersion in the turbulent recirculation zones of sudden expansion pipe flows

    Torres, Josefina; García García, Javier
    The dispersion of solid particles in the turbulent recirculation zones of sudden expansion pipes can be characterized by different Stokes numbers and mean drift parameter and its study is important because this kind of flows appears in many technological applications.

  14. Comparison of particle dispersion obtained with simple stochastic models and les in pipe flow

    García García, Javier; Crespo Martínez, Antonio; Torres, Josefina
    A hybrid Eulerian-Lagrangian approach is employed to simulate heavy particle dispersion in turbulent pipe flow. The mean flow is provided by the Eulerian simulations developed by mean of JetCode, whereas the fluid fluctuations seen by particles are prescribed by a stochastic differential equation based on normalized Langevin. The statistics of particle velocity are compared to LES data which contain detailed statistics of velocity for particles with diameter equal to 20.4 µm. The model is in good agreement with the LES data for axial mean velocity whereas rms of axial and radial velocities should be adjusted.

  15. Diseño y construcción de una bomba manual de émbolo para cisternas de aguas pluviales y pozos someros

    Polo Castaño, Christian Daniel
    El objetivo de este proyecto es hacer un estudio sobre las bombas manuales de émbolo como tecnología social, analizando su implicación en el “Programa Um Milhão de Cisternas” – Programa un millón de cisternas - (P1MC) que se desarrolla en el semiárido brasileño basado en la recogida de agua de lluvia, ya que es una de las formas más sencillas y de bajo costo para paliar el déficit de agua en la región. El caso de estudio serán las bombas Carcará I y II cuya fabricación se hace con elementos de PVC y canicas, así como la construcción de la bomba...

  16. Prediction of wake effects on wind farm power production using a RANS approach. Part II. Offshore: Case studies from the UPWIND project

    Cabezón Martínez, Daniel; Sumner, J.; Crespo Martínez, Antonio
    The estimation of power losses due to wind turbine wakes is crucial to understanding overall wind farm economics. This is especially true for large offshore wind farms, as it represents the primary source of losses in available power, given the regular arrangement of rotors, their generally largerdiameter and the lower ambient turbulence level, all of which conspire to dramatically affect wake expansion and, consequently, the power deficit. Simulation of wake effects in offshore wind farms (in reasonable computational time) is currently feasible using CFD tools. An elliptic CFD model basedon the actuator disk method and various RANS turbulence closure schemes...

  17. Validation of a CFD wake model based on the actuator disk technique and the thrust coefficient. Preliminary results

    Cabezón Martínez, Daniel; Sanz Rodrigo, Javier; Martí Pérez, Ignacio; Crespo Martínez, Antonio
    A simplified CFD wake model based on the actuator-disk concept is used to simulate the wind turbine, represented by an actuator disk upon which a distribution of forces, defined as axial momentum sources, are applied on the incoming flow. The rotor is supposed to be uniformly loaded, with the exerted forces as a function of the incident wind speed, the thrust coefficient and the rotor diameter. The model is validated through experimental measurements downwind of a wind turbine in terms of wind speed deficit. Validation on turbulence intensity will also be made in the near future.

  18. CFD modelling of the interaction between the Surface Boundary Layer and rotor wake. Comparison of results obtained with different turbulence models and mesh strategies

    Cabezón Martínez, Daniel; Sanz Rodrigo, Javier; Martí Pérez, Ignacio; Crespo Martínez, Antonio
    A simplified CFD wake model based on the actuator disk concept is used to simulate the wind turbine, represented by a disk upon which a distribution of forces, defined as axial momentum sources, are applied on the incoming non-uniform flow. The rotor is supposed to be uniformly loaded, with the exerted forces function of the incident wind speed, the thrust coefficient and the rotor diameter. The model is tested under different parameterizations of turbulence models and validated through experimental measurements downwind of a wind turbine in terms of wind speed deficit and turbulence intensity.

  19. Gear dynamics monitoring using discrete wavelet transformation and multi-layer perceptron neural networks

    Sanz, Javier; Perera Velamazán, Ricardo; Huerta Gomez de Merodio, M. Consuelo
    This paper presents a multi-stage algorithm for the dynamic condition monitoring of a gear. The algorithm provides information referred to the gear status (fault or normal condition) and estimates the mesh stiffness per shaft revolution in case that any abnormality is detected. In the first stage, the analysis of coefficients generated through discrete wavelet transformation (DWT) is proposed as a fault detection and localization tool. The second stage consists in establishing the mesh stiffness reduction associated with local failures by applying a supervised learning mode and coupled with analytical models. To do this, a multi-layer perceptron neural network has been...

  20. Parameterization of the atmospheric boundary layer for offshore wind resource assessment with a limited length-scale k-ε model

    Sanz Rodrigo, Javier; Cabezón Martínez, Daniel; Lozano, Sergio; Martí Pérez, Ignacio
    The structure of the atmospheric boundary layer (ABL) is modelled with the limited- length-scale k-ε model of Apsley and Castro. Contrary to the standard k-ε model, the limited-length-scale k-ε model imposes a maximum mixing length which is derived from the boundary layer height, for neutral and unstable atmospheric situations, or by Monin-Obukhov length when the atmosphere is stably stratified. The model is first verified reproducing the famous Leipzig wind profile. Then the performance of the model is tested with measurements from FINO-1 platform using sonic anemometers to derive the appropriate maximum mixing length.

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