(Naval) Artículos

URI permanente para esta colecciónhttps://inta.metricsalad.com/handle/123456789/74

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Aerodynamic Flow Effects on Aircraft Carrier Takeoff Performance
(Aerospace Research Central, 2019-01-11) Bardera, Rafael; García Magariño, A.; Rodríguez Sevillano, A.; Barcala Montejano, M. Á.; Instituto Nacional de Técnica Aeroespacial (INTA)
The aircraft takeoff maneuver for onboard operations is the most critical aspect of maritime performance. In the last decades, several improvements have been made to reduce the number of accidents. One of them is the ski-jump ramp, a modern takeoff system that allows the maneuver to be performed more safely and using less runway distance. Thus, a new in-depth aerodynamic study of the ramp is required. A wind-tunnel test campaign was developed to study the disturbances caused by the ski-jump ramp over the flight deck and the influence on an aircraft carrier performance. Smoke visualizations over the ramp revealed a detached unsteady recirculation bubble at the ramp and a turbulent flow over the flight deck. Velocity measurements were carried out by means of particle image velocimetry. The influence of these disturbances was evaluated for the takeoff performance of the AV-8B Harrier II. The results proved the importance of taking into account these disturbance effects and provided a detailed characterization of the flow over the carrier deck, resulting in establishment of a useful background for future studies on aircraft–ship interference.
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Scale Effects on Heave Plates for Semi-Submersible Floating Offshore Wind Turbines: Case Study With a Solid Plain Pla
(ASME, 2019-01-28) Bezunartea Barrio, A.; Fernández Ruano, S.; Marón Loureiro, A.; Molinelli Fernández, E.; Moreno Burón, F.; Oria Escudero, J.; Ríos Tubio, J.; Soriano Gómez, C.; López Pavón, C.; Souto Iglesias, A.; Valea Peces, Álvaro
In the case of SPAR or semi-submersible platforms for floating wind turbines, it is beneficial in some cases to use heave plates that reduce their heave motion amplitude and/or tune their heave natural period. As part of the Hiprwind project, it was decided to study scale effects on the hydrodynamics of this element. To this aim, models of one leg of the platform, equipped with a heave plate without any reinforcements, were built. This model is a simplified representation of the actual one, which incorporates a vertical flap on the heave plate edge. The scales were 1:20, 1:27.6, and 1:45.45, with the former leading to added mass values of the order of 300 kg, becoming one of the largest models for which experiments with heave oscillations have been carried out. Decay tests starting from various amplitudes and forced oscillations tests for a range of frequencies and amplitudes were performed. It is shown in the paper that the influence of the scale factor on the hydrodynamic coefficients is weaker than the effect that the motion amplitude (characterized with the Keulegan–Carpenter (KC) number produces in them. This result is relevant because the selection of a representative KC is an important and somewhat arbitrary aspect to be set in the linear potential simulation codes in order to add viscous damping. What has been shown herein is that a right selection of KC has a larger impact on the models than the uncertainties due to eventual scale effects in the heave-plates dynamics.
Restringido
Scale Effects in Heave Plates: PIV Investigation
(ASME, 2020) Anglada Revenga, E.; Bezunartea Barrio, A.; Marón Loureiro, A.; Molinelli Fernández, E.; Oria Escudero, J.; Saavedra Inocente, L.; Soriano Gómez, C.; Duque Campayo, D.; Gómez Goni, J.; Souto Iglesias, A.
Bezunartea et al. Scale Effects on Heave Plates for Semi-Submersible Floating Offshore Wind Turbines: Case Study With a Solid Plain Plate (Journal of Offshore Mechanics and Arctic Engineering, Vol. 11, pp 1–14, 2019) studied scale effects on the hydrodynamics of heave plates by conducting model scale experimental tests. Three models with different scales of one leg of the HiPRWind platform, equipped with a plain heave plate, were built and tested with forced harmonic heave motions. They showed that the influence of the model scale on the coefficients is clearly weaker than that of the heave motion amplitude. Among the pending tasks in that work was to conduct velocity field measurements of the flow with Particle Image Velocimetry techniques (PIV). This paper discusses some of the results of such measurements, carried out forcing vertical harmonic motions. In these measurements, it is assessed how significant scale effects are also in the local kinematics of the flow, thus complementing the global ones carried out in the referred work. From velocity and vorticity graphs, the flows show great similarities across the three scales, consistent with the ones found in the prequel paper. A metric has been developed whose outcomes are aligned with these results but further work is necessary to develop key indicators to compare flow fields from PIV across different scales.
Acceso Abierto
Balance measurements on a frigate type ship model
(Elsevier, 2020-10-12) Bardera, Rafael; García Magariño, A.
Balance measurements performed by testing sub-scaled ship models determine the global forces and moments acting on the ship, which allows knowing the power required for the ship's movement and provides insight to be applied in the design of the control systems used to steer the ship and to avoid instabilities while sailing. The ship superstructure may produce large separated regions and high air wake turbulence levels resulting in a set of fluctuations of the flow parameters usually determined by measuring velocity or pressure. This paper presents the balance measurement of the aerodynamic forces acting on the ship hull. Aerodynamic forces and moments produced on the ship can be interpreted as an integration of the flow parameters (velocity and pressure distributions) over the ship surface wetted by the air. Balance method provides averaged values and fluctuations of forces coefficients. Aerodynamic environment in the vicinity of a ship is influenced by a large number of factors (atmospheric wind, sea state, ship superstructure, masts, stacks, antennas…) affecting helicopter operations on board ships and their safety during the take-off and landing manoeuvres.
Restringido
Aerodynamic optimization over frigate helicopter flight deck by Hangar shape modifications
(Elsevier, 2020-11-16) Bardera, Rafael; Matías García, J. C.; García Magariño, A.
Helicopter operations on frigates imply complex maneuvers for pilots. During the aircraft approach to the frigate, the helicopter rotor is immersed in a changing aerodynamic flow, with high speed and turbulence intensity gradients. This occurs as a consequence of the nonaerodynamic surfaces that compose the frigates and generate detached flow on their decks. Typically, the helicopter operations on frigates are located at the stern. That is, after the superstructure of the ship and just behind the hangar where the helicopter can be hosted. Using a simplified frigate shape model, tests have been carried out at the National Institute of Aerospace Technology’s low-speed wind tunnel by modifying the hangar geometry in a bubble-shaped way to optimize it aerodynamically and improve the flow over the frigate aftdeck. Roof and side walls have been modified by linearA, circular C, and elliptical E geometries. A particle image velocimetry (PIV) technique has been used for obtaining the flow velocity field above and behind the hangars proposed to evaluate the effectiveness of each geometry modification proposed. Finally, a numerical comparison with the PIV results and parameters such as the storage capacity reduction of the hangar due to its geometry change has been carried out.
Acceso Abierto
Los materiales compuestos en el ICTS-CEHIPAR
(AEMAC- Asociación Española de Materiales Compuestos, 2021-01-18) Martínez, J. L.; González Gallego, M.; Terroba, F.; Frövel, M.; Valle, Jesús; Serna, M. C.; de la Rosa Escribano, Juan Carlos; Martínez, J. L. [0000-0001-9046-8237]
El Centro de Experiencias Hidrodinámicas de El Pardo (ICTS-CEHIPAR), considerado como Infraestructura Científica y Técnica Singular (ICTS), es parte de la Subdirección General de Sistemas Navales (SGSN) del Instituto Nacional de Técnica Aeroespacial “Esteban Terradas” (INTA). En el Departamento de Tecnología y Ensayos del ICTS-CEHIPAR, se ha creado recientemente una línea de investigación aplicada a la industria naval y centrada en el estudio de materiales compuestos. En esta línea de investigación se ha marcado como objetivo la monitorización de esfuerzos estructurales en materiales compuestos mediante sensores de fibra óptica en redes de Bragg de difracción (FBGS). Desde el ICTS-CEHIPAR se persigue la mejora de los procedimientos constructivos de modelos para buques y artefactos navales y por ello, el uso de materiales compuestos en estos procedimientos. En este sentido, la implementación de técnicas de instrumentación para la monitorización de esfuerzos en dichos materiales es necesaria para detectar posibles daños debidos a diferentes causas que pueden ocurrir a lo largo de su vida útil. Los resultados obtenidos en los ensayos a escala permitirán aplicar a buques reales las metodologías de fabricación e instrumentación estudiadas, con el fin de incrementar su seguridad y optimizar su mantenimiento.
Acceso Abierto
Monitorización estructural del RPAS MILANO en la fase de ensayos en vuelo
(AEMAC- Asociación Española de Materiales Compuestos, 2021-04-15) Frövel, M.; Terroba, F.; Cabezas, J.; Güemes, A.; García Ramírez, J.; Reyes, E.; Fernández, A.; Plaza del Pino, Juan Carlos
El RPAS (Remote Piloted Air System) MILANO es el mayor sistema aéreo no tripulado desarrollado por INTA, pretende convertirse en una plataforma de investigación capaz de realizar ensayos en vuelo conmultitud de cargas de pago científicas complementando de este modo a las plataformas Aéreas de Investigación (PAIs) tripuladas del propio INTA. A nivel estructural, el RPAS MILANO está realizadoen su práctica totalidad en material compuesto de carbono/epoxi de curado fuera de autoclave y en su diseño se han seguido las normativas de aeronavegabilidad aplicables al tipo de aeronave(STANAG-4671). En el mes de Diciembre del 2018 ha comenzado la fase de ensayos en vuelo del RPAS MILANO y su sistema de detección de daño y uso (SHM) se está empleando para recoger datos antes, después y durante los vuelos, proporcionando una información muy útil a la hora de evaluar y analizar el estado de la estructura y la posible aparición de sobrecargas estructurales no previstas durante la misión. La información sobre eventos especiales, como el aterrizaje forzoso o la carga de ráfagas, se puede proporcionar a los operadores de mantenimiento después de cada vuelo.El modelo de simulación y sus predicciones se han validado en una estructura real del fuselaje posterior del MILANOy en la que se introducendaños reales de tamaños mayores al eliminar remaches progresivamente. En nuestro estudio, se utilizan tres algoritmos diferentesde detección de daño, basados en un índicede daño, PCA y Artificial Neural Networks (ANN), respectivamente. The RPAS (Remote Piloted Air System) MILANO is the largest unmanned aerial system developed by INTA thataims to become a research platform capable of carrying out in-flight tests with many scientific payload, thus complementing the Air Research Platforms (PAIs) of INTA. At the structural level, the RPAS MILANO is made in its entirety in carbon / epoxy composite material that is cured out of the autoclave. Its design has been followed by the airworthiness regulations applicable to the aircraft type (STANAG-4671). In the month of December 2018, the RPAS MILANO flight test phase began and it’sHealth and Usage Monitoring System (HUMS) is being used to collect data before, after and during flights, providing very useful information when evaluating and analyzingthe state of the structure and the possible appearance of structural overloads not foreseen during the mission. Information about special events, such as forced landing or burst loading, can be provided to maintenance operators after each flight.The simulation model and its predictions have been validated in a real structure of the rear fuselage of theMILANOand in which real damage of larger sizes is introduced by eliminating rivets progressively. In our study, three different damage detection algorithms are used, based on adamageindex, PCA and Artificial Neural Networks (ANN).
Acceso Abierto
Ensayos biaxiales sobre sensores de fibra óptica basados en redes de Bragg
(AEMAC- Asociación Española de Materiales Compuestos, 2021-07-19) González Gallego, M.; Terroba, F.; Frövel, Malte; Moravec, C.; Martínez, J. L.; Serna, M. C.
Los sensores de fibra óptica basados en redes de Bragg, ampliamente usados en sistemas de monitorización estructural, son sensores cuyo funcionamiento es perfectamente conocido desde el punto de vista teórico cuando son sometidos a deformaciones en la dirección de la propia fibra. No obstante, las deformaciones transversales tienen efecto en el comportamiento de la fibra óptica como sensor, aunque dicho efecto ha sido menos estudiado y es menos conocido. Cuando un sensor se encuentra embebido en una estructura de material compuesto, sudeformación rara vez es unidireccional, debido a la presencia de estados de carga complejos o al efecto que el módulo de Poisson tiene sobre la deformación del propio laminado.El objetivo del trabajo es someter al sensor a un estado de deformación controlado en los dos ejes del plano principal mediante la aplicación de cargas perpendiculares entre sí. Para ello, se va a realizar una campaña de ensayos biaxiales sobre probetas de material compuesto con sensores de fibra óptica embebidos. Con esta metodología de ensayos en el plano, se observará la influencia de las deformaciones transversales en los valores de deformación longitudinal medidos por el sensor.Para la realización de los ensayos biaxiales se ha utilizadouna máquina de ensayos que permite controlar las cargas aplicadas en las tres direcciones espaciales de forma independiente y un equipo de medición de deformaciones mediante correlación digital de imagen (CDI). De esta forma, se realizará una caracterización del sensor antes dicho bajo un estadode cargas. Bragg Grating based optical fibre sensors are widely used for structural monitoring. Its operation is theoretical well known when deformations are measured along the fibre axes. Nevertheless, transversedeformations of the optical fibre have an effect thataffects the performance of the sensors. This transverse effect has not been so deeply studied as the longitudinal and it is less known. When a sensor is embedded in a composite structure, its deformation is rarely unidirectional because of the presence ofcomplex loads cases and/or the Poisson module effect on the deformation of the lamination. A test campaign of biaxial composite material specimens with embedded fibre optic sensors is going to be performed. The work pursues to create controlled deformation cases to the sensor in the two main axes of its plane, by means of perpendicular loads in each axis. Following this test methodology in the plane, it will be observed the influence of the transverse deformations on the values of the longitudinal deformation measured by the sensors. To carry out the biaxial tests it has been used equipment that allows the control of the applied load in the three coordinate axes independently. It also been used a digital image correlation (DIC) equipment for measuring the deformations. Characterization of the sensors will be carried out with different load case tests.
Acceso Abierto
EL ENSAYO DE AUTOPROPULSIÓN. UNA NUEVA VISIÓN DE UN ENSAYO CLÁSICO EN LOS CANALES DE EXPERIENCIAS.
(Cehipar, 2021-10-01) Ponce Gómez, Juan Manuel
La experimentación con modelos físicos ha sido tradicionalmente la actividad básica de los Canales de Experiencias. Los continuos avances de los sistemas informáticos hacen que simulaciones numéricas CFD tengan un futuro prometedor. No obstante, en la actualidad, ensayar con modelos es el procedimiento más fiable para obtener valores numéricos de los parámetros fundamentales de la propulsión de un buque, de acuerdo con procedimientos recomendados por la ITTC1 En lo que se refiere a la realización práctica de las técnicas experimentales, la ITTC tiene también algunas recomendaciones. No obstante, son algo genéricas y no tienen en cuenta muchos aspectos prácticos. Por ello, cada canal tiene su propia forma de realizar los ensayos de acuerdo con los procedimientos recomendados. No obstante, se dan por buenos métodos experimentales que vienen siendo utilizados durante años y se presta más atención a la mejora de los procedimientos de extrapolación. En este artículo se hace una revisión de la metodología utilizada, tradicionalmente, para la realización del ensayo de autopropulsión. Se presenta un criterio para valorar su calidad y también, un procedimiento experimental que simplifica notablemente su realización y que, a su vez, aumenta notablemente la fiabilidad del ensayo.
Acceso Abierto
Monotorización de la salud estructural de un material compuesto mediante sensores FBGS
(Sociedad Española de Materiales, 2022-06-02) González Gallego, M.; Martínez, J. L.; Terroba, F.; Frövel, M.; Ministerio de Ciencia e Innovación (MICINN)
En este trabajo se presenta la campaña de ensayos biaxiales llevada a cabo con el fin de caracterizar la influencia de cargas transversales en los sensores de fibra óptica en redes de Bragg (FBGS) con diferentes materiales de recubrimiento. Para la caracterización de los sensores FBG se ha optado por un diseño de probeta con geometría cruciforme, como medio material estructural de análisis del campo de deformaciones. En estas probetas, los sensores se han colocado en la zona central, alineada con dos de los brazos y perpendicular a los otros dos. Los ensayos biaxiales se han prolongado hasta alcanzar el 70% de la carga máxima soportada por el material compuesto, con el que está fabricada la probeta cruciforme. Las probetas ensayadas se han laminado a partir de tejido unidireccional reforzado con fibra de carbono y resina epoxi, utilizado en estructuras monolíticas navales. Este proyecto de investigación se enmarca en el Convenio de colaboración existente entre INTA y la UCLM.
Acceso Abierto
Micro/Bubble drag reduction focused on new applications
(Multidisciplinary Digital Publishing Institute (MDPI), 2023-06-28) García Magariño, A.; López Gavilan, Pablo; Terroba, F.; Sor, Suthyvann; Instituto Nacional de Técnica Aeroespacial (INTA)
Bubble drag reduction has been shown to be a promising technique for reducing the drag in ships, thus reducing the emission of pollutants and allowing the compliance with the new requirements imposed recently in this respect. Different searches have been conducted in the publications related to this technique, and an increase in interest has been shown, especially in the last decade. In this context, a review of the experimental work related to bubble drag reduction published in the last decade is presented in the present article. The works were classified according to the facility used (towing tank, cavitation tunnel, water channel, Taylor–Couette…), and the main finding are presented. It was found that two new trends in research have arisen, while there are still contradictions in the fundamental basis, which needs further study.
Acceso Abierto
Fiber bragg gratings sensor strain–optic behavior with different polymeric coatings subjected to transverse strain
(Multidisciplinary Digital Publishing Institute (MDPI), 2024-04-27) González Gallego, Manuel; Terroba, F.; Martínez, J. L.; González del Val, Miguel; López Cela, Juan José; Frövel, M.; Instituto Nacional de Técnica Aeroespacial (INTA); Ministerio de Ciencia e Innovación (MICINN)
This research work is based on a previous study by the authors that characterized the behavior of FBG sensors with a polyimide coating in a structural monitoring system. Sensors applied to structural health monitoring are affected by the presence of simultaneous multidirectional strains. The previous study observed the influence of the transverse strain (ey) while keeping the longitudinal strain constant (ex), where the x direction is the direction of the optical fiber. The present study develops an experimental methodology consisting of a biaxial test plan on cruciform specimens with three embedded FBG sensors coated with polyimide, acrylate, and ORMOCER®. Applying the Strain–Optic Theory as a reference, a comparison of the experimental values obtained with the different coatings was studied. This experimental work made it possible to study the influence of the transverse strain (ey) on the longitudinal measurements of each FBGS and the influence of the coating material. Finally, the calibration procedure was defined as well as K (strain sensitivity factor) for each sensor.

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