(Naval) Artículos

URI permanente para esta colecciónhttps://digitalpro.inta.es/handle/20.500.12666/74

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Aerodynamic Flow Effects on Aircraft Carrier Takeoff Performance
(Aerospace Research Central, 2019-01-11) Bardera, Rafael; García-Magariño, Adelaida; 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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Aerodynamic optimization over frigate helicopter flight deck by Hangar shape modifications
(Elsevier, 2020-11-16) Bardera, Rafael; Matías García, J. C.; García-Magariño, Adelaida
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
Balance measurements on a frigate type ship model
(Elsevier, 2020-10-12) Bardera, Rafael; García-Magariño, Adelaida
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.
Acceso Abierto
Design Process and Advanced Manufacturing of an Aquatic Surface Vehicle Hull for the Integration of a Hydrogen Power Plant Propulsion System
(Multidisciplinary Digital Publishing Institute (MDPI), 2024-02-01) Renau Martínez, Jordi; García Peñas, Víctor; Ibáñez Arnal, Manuel; Giménez Sancho, Alberto; López González, E.; García-Magariño, Adelaida; Terroba, Félix; Moreno Ayerbe, Francisco Javier; Sánchez López, Fernando; Ministerio de Ciencia e Innovación (MICINN)
This article presents the design and manufacturing of a hydrogen-powered unmanned aquatic surface vehicle (USV) hull. The design process comprised three stages: (1) defining the requirements for a preliminary geometry, (2) verifying the hydrodynamic hull performance using computational fluid dynamics (CFD) simulations, and (3) experimentally validating the hydrodynamic hull performance and CFD analysis results through experimental fluid dynamics in a calm water towing tank. The manufacturing process utilized additive manufacturing technologies, such as fused granular fabrication and selective laser sintering, to produce the hull and other components, including the propeller and the rudder; thermoplastic materials with carbon fiber reinforcement were employed. The experimental results demonstrate that the optimized trimaran hull exhibited low hydrodynamic resistance (7.5 N), high stability, and a smooth flow around the hull (up to 2 m/s). The design and manufacturing of the USV hull met expectations from both hydrodynamic and structural perspectives, and future work was outlined to integrate a power plant, navigation system, and scientific equipment.
Acceso Abierto
Micro/Bubble drag reduction focused on new applications
(Multidisciplinary Digital Publishing Institute (MDPI), 2023-06-28) García-Magariño, Adelaida; López Gavilán, Pablo; Sor, Suthyvann; Terroba, Félix; 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
Practical Design of a Low-Cost Icing Wind Tunnel for Unmanned Aerial Vehicle Testing in a Limited Space
(Multidisciplinary Digital Publishing Institute (MDPI), 2024-08-07) Plaza del Pino, Juan Carlos; Terroba, Félix; García-Magariño, Adelaida; Atienza, R.; Mora Nogués, Julio; Instituto Nacional de Técnica Aeroespacial (INTA)
Ice accretion on aircrafts due to atmospheric conditions is still a relevant research topic, especially in the case of Unmanned Aerial Vehicles (UAVs), due to their smaller size and the relative underdevelopment of ice protection systems (anti-icing and de-icing) for these aircraft. For the research and development of these systems, it is necessary to assess their performance in icing wind tunnels (IWTs), which are generally high-cost facilities. This article describes the design and building process of a new IWT for testing fixed-wing UAVs, aimed at cost reduction and restricted to an existing cold climate chamber of limited size. The designed IWT is an open-circuit type with two corners, a test section size of 0.40 m × 0.27 m and speed up to 70 m/s. The design process employs widely used and proven semi-empirical formulas, supported by detailed calculations using Computational Fluid Dynamics (CFD) tools, to achieve a test section core of useful quality and avoid flow separation. Theoretical limits with respect to a usable droplet size and Liquid Water Content (LWC) are calculated, and the test section core is estimated. The design process followed proves to be a very good approach to the design and aerodynamic optimisation of a low-cost IWT.

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Examinando (Naval) Artículos por Autor "García-Magariño, Adelaida"