(Aeronáutica) Artículos
URI permanente para esta colecciónhttps://inta.metricsalad.com/handle/123456789/48
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Examinando (Aeronáutica) Artículos por Autor "Bardera, Rafael"
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Publicación Restringido A comparative analysis of helicopter recovery maneuvers on a SFS by means of PIV and balance measurements(Elsevier, 2023-05-23) Matías García, J. C.; Bardera, Rafael; Franchini, Sebastián; Barroso, Estela; Sor, Suthyvann; Instituto Nacional de Técnica Aeroespacial (INTA)The flow field around a frigate is complex due to flow detachments, high velocity gradients, and flow unsteadiness. These flow patterns can endanger helicopter operations around frigates and increase pilot workload above the flight deck. This paper contains a comparative analysis of three different recovery maneuvers: an approach from the stern in the centerline plane (S); a diagonal maneuver (D); and an L-shaped maneuver. The comparison is made using wind tunnel tests with a scaled frigate and a motorized helicopter. For the three maneuvers, velocity contours around the helicopter with Particle Image Velocimetry are obtained. An internal balance is also used to obtain forces and moments on the helicopter during the flight path of the maneuvers. Those measurements show that the wake of the ship mostly affects longitudinal and thrust forces. In addition, pitch torque is highly reduced when the helicopter is behind the frigate superstructure, and the roll moment is also important when the wind angle increases. In the end, an estimation of pilot workload is presented to conclude that L-shaped maneuver is the best for 0° and small WOD angles and D or S recoveries for moderately high negative WOD angles.Publicación Restringido Characterization of an electrostatic filter prototype for bioaerosol flowmetering for INTA Investigation Aerial Platforms(Elsevier, 2019-08-20) Bardera, Rafael; García Magariño, A.; González, Elena; Aguilera, Á.; Sor, Suthyvann; Instituto Nacional de Técnica Aeroespacial (INTA)The characterization of the airborne microorganisms at different altitudes of the atmosphere is usually conducted by means of aerial platforms. It is very interesting to know the biological processes in the atmosphere. However, there are problems associated to the fact that sampling systems are embarked on an aircraft and the low presence of microorganisms at high altitude. A prototype of a new electrostatic filter for bioaersol flowmetering dedicated to biology investigations has been developed. This prototype was designed to be installed on board in aerial platforms of INTA. The experimental characterization of the aerodynamic flow was performed in order to investigate the behaviour of the filter when different air intake widths and different mechanical deflectors are employed. A combination of these impactor with the filters based on industrial electrostatic precipitator technology have been studied. Non-intrusive Particle Image Velocimetry technique has been used to measure the flow field inside the filter when it was running under controlled conditions in laboratory. This study is a first investigation on the flow field of filter for bioaerosol flowmetering to be embarked on an aircraft. The results show the influence of each parameter in the flow field that could be used for further investigations and designs.Publicación Acceso Abierto Development and characterization of a low-cost wind tunnel balance for aerodynamic drag measurements(IOP Science Publishing, 2019-06-17) Bardera, Rafael; García Magariño, A.; Matías García, J. C.; Donoso, Eduardo; Sor, Suthyvann; Instituto Nacional de Técnica Aeroespacial (INTA)Drag force measurement is one of the most important data that can be obtained in wind tunnel tests. Drag force is directly related to the energy that a vehicle needs to move, and, therefore, to the fuel costs associated with it. For vehicles, drag forces are usually measured in wind tunnels. The typical instruments for drag measurement are the force balances, which are usually complex and expensive instruments. The aim of this investigation is to study the development of a low-cost in-house balance for drag measurements in a wind tunnel. Based on a commercial available load cell XFTC300 Series in combination with simple elements designed and manufactured at INTA, a balance capable of measuring the drag force to models in a considerably wide adjustable range has been developed and characterized. The balance has been calibrated and used in a wind tunnel. Tests were carried out on a truck model, a simplified frigate shape and an Ahmed Body to obtain the resistance coefficient and evaluate the operation of the balance.
