Persona: Rafael, Bardera Mora
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Rafael
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Bardera Mora
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Publicación Restringido Optimization of passive flow control above the ski jump ramp of an aircraft carrier by CFD and experimental investigation(Elsevier, 2022-11-22) Rafael, Bardera Mora; Matías García, J. C.; Instituto Nacional de Técnica Aeroespacial (INTA)Aircraft carriers are a very useful operational tool for military operations. They are designed to provide service to aircraft at sea. For that reason studying the aerodynamic flow on their decks is essential. During take-off and landing maneuvers the aircraft can be affected by the turbulent flow generated by the non-aerodynamic surfaces that compose the geometry of the ship. Specifically, this study uses Computational Fluid Dynamics (CFD) applied to an aircraft carrier. The goal is to analyze and modify the flow detachment generated by the ski jump ramp on the flight deck that can affect the aircraft performances during take-off maneuvers. Passive flow control techniques such as holes in the ramp to allow airflow entering over the deck or aerodynamic devices added in the ramp corner have been tested. Different parameters of the devices have been studied and partial and even complete elimination of the flow detachment has been achieved. Finally, the numerical model has been compared with experimental wind-tunnel tests. They have demonstrated a full elimination of the flow detachment and up to 80% of turbulence intensity reduction above the ski jump ramp of the aircraft carrier.Publicación Restringido Mars 2020 Wind Velocity Measurement Interferences at High Reynolds Numbers(Aerospace Research Central, 2019-12-29) García-Magariño, Adelaida; Sor, Suthyvann; Rafael, Bardera Mora; Muñoz, Javier; Instituto Nacional de Técnica Aeroespacial (INTA)The Mars Environmental Dynamics Analyzer will be dedicated to getting meteorological data from Mars during NASA’s Mars 2020 rover mission. High-quality Mars atmosphere measurements are required in order to build mathematical models of the climate on a planetary scale. The Mars 2020 rover will be equipped with two wind sensors installed on two separated booms working in active redundancy but producing a mutual aerodynamic interference on one another’s wind measurements. This paper presents a systematic study on the interferences produced by the sensors and the rover body itself when measuring wind velocities in order to get insight to assess the uncertainties produced by this effect.Publicación Acceso Abierto Interferometric laser imaging for droplet sizing method for long range measurements(Elsevier, 2021-01-15) García-Magariño, Adelaida; Sor, Suthyvann; Muñoz Campillejo, Javier; Rafael, Bardera Mora; Instituto Nacional de Técnica Aeroespacial (INTA)A recent appendix in the aircraft regulations comprises testing supercooled large droplets impinging on its surfaces. For those tests, the size and distributions of droplets need to be characterized in icing wind tunnels. In this paper, the applicability of implementation of the “Interferometric Laser Imaging for Droplet Sizing” technique inside a wind tunnel with a 3 m × 2 m open elliptical test section has been discussed. Experiments have been conducted in the laboratory for the discussion at object distance of 1.6 m and 2.29 m and droplets diameters between 360 µm and 850 µm. All the streams were previously characterized by means of the shadowgraph imaging technique. A novel approach of the Interferometric Laser Imaging for Droplet Sizing technique where droplets are not fully defocused to avoid excessive overlapping is presented. Two new image processing approaches provide in general good results as compared to previous methods.Publicación Acceso Abierto Numerical Analysis of Bioinspired Tails in a Fixed-Wing Micro Air Vehicle(Multidisciplinary Digital Publishing Institute (MDPI), 2023-09-08) Rafael, Bardera Mora; Barroso, Estela; Rodríguez Sevillano, A.; Matías García, J. C."Bird tails play a key role in aerodynamics and flight stability. They produce extra lift for takeoff and landing maneuvers, enhance wing functions and maintain stability during flight (keeping the bird from yawing, rolling and pitching, or otherwise losing control). This paper investigates the use of bioinspired horizontal stabilizers for Micro Air Vehicles (MAVs) involving a Zimmerman wing-body geometry. A selection of five tail shapes of the main types existing in nature is presented, and a parametric analysis is conducted looking into the influence of the most relevant tail geometric parameters to increase the longitudinal static stability of the vehicle. Based on the parametric study, a smaller subset of candidate tail designs are shortlisted to perform a detailed aerodynamic analysis. Then, steady RANS CFD simulations are conducted for a higher-fidelity study of these candidate tail designs to obtain an optimum of each tail type. The criterion for selection of the optimum tail configuration is the maximum aerodynamic efficiency, CL /CD , as well as a high longitudinal static stability. The squared-fan tail provides the highest aerodynamic efficiency while maintaining a high longitudinal stability of the vehicle. In conclusion, this paper provides an innovative study of improving longitudinal stability and aerodynamics through the implementation of bioinspired horizontal stabilizers in vehicles with these characteristics."Publicación Restringido Mars 2020 Rover Influence on Wind Measurements at Low Reynolds Number(Aerospace Research Central, 2019-02-11) Rafael, Bardera Mora; García-Magariño, Adelaida; Sor, Suthyvann; Urdiales, María del Mar; Instituto Nacional de Técnica Aeroespacial (INTA)The Mars 2020 rover is the new vehicle dedicated to the Martian surface investigation. This vehicle will transport Mars Environmental Dynamic Analyzer, the new meteorological station, including two wind sensors installed in the camera mast. An experimental characterization was conducted to investigate the influence of the Mars 2020 rover in the Mars Environmental Dynamic Analyzer wind measurements at low Reynolds numbers. Wind tunnel experiments were conducted using a 1:45th scaled model in a wind tunnel specially designed for these experiments. The velocity was measured using laser Doppler anemometry. A method is proposed in this investigation to calculate a correction factor for the data measurements of wind sensors embarked on rovers dedicated to planetary exploration missions. In particular, the method was applied to wind measurements taken by Mars Environmental Dynamic Analyzer in the Mars 2020 rover using the laser Doppler anemometry measurements, and corrections up to 40% in the velocity magnitude and 23 deg in the deflection angle were found.Publicación Acceso Abierto From conventional to bioinspired: Evolution of tail surface designs in micro air vehicles(Elsevier, 2024-12-23) Rodríguez Sevillano, A.; Rafael, Bardera Mora; Barroso, Estela; Matías García, J. C.; López Cuervo, Alejandra; Instituto Nacional de Técnica Aeroespacial (INTA)The paper presents the evolution of the tail surface design of a micro air vehicle based on adaptive wing geometry. The initial prototype was conceived as a tailless aircraft geometry, waiting for future innovations and stability augmentations. An initial experimental test bench will be presented to characterize the variation of wing profile curvature as a function of the voltage, through MFC actuators. Once these results have been analyzed, the process of conceiving a conventional T-tail was initiated, ultimately evolving toward the proposal of a bioinspired tail based on the tail shape of various birds. The results obtained in wind tunnel tests using PIV techniques will be presented. The results validate the selected tail surface design as an appropriate geometry for a bioinspired micro air vehicle.Publicación Acceso Abierto Aerodynamic investigation of a morphing wing for micro air vehicle by means of PIV(MDPI, 2020-10) Rafael, Bardera Mora; Rodríguez Sevillano, A.; García-Magariño, Adelaida; Ministerio de Defensa; García Magariño, A. [0000-0002-6039-8407]A wind tunnel tests campaign has been conducted to investigate the aerodynamic flow around a wing morphing to be used in a micro air vehicle. Non-intrusive whole field measurements were obtained by using PIV, in order to compare the velocity and turbulence intensity maps for the modified and the original version of an adaptive wing designed to be used in a micro air vehicle. Four sections and six angles of attack have been tested. Due to the low aspect ratio of the wing and the low Reynold number tested of 6.4 × 104, the influence of the 3D effects has been proved to be important. At high angles of attack, the modified model prevented the detachment of the stream, increased the lift of the wing and reduced the turbulence intensity level on the upper surface of the airfoil and in the wake.Publicación Acceso Abierto Selection criteria for biplane wing geometries by means of 2D wind tunnel tests(Multidisciplinary Digital Publishing Institute (MDPI), 2022-05-16) Rodríguez Sevillano, A.; Barcala Montejano, M. Á.; Rafael, Bardera Mora; García-Magariño, Adelaida; Rodríguez Rojo, María Elena; Morales Serrano, Sara; Fernández Antón, Jaime; Instituto Nacional de Técnica Aeroespacial (INTA)This paper presents a study based on wind tunnel research on biplane configurations. The objective of this research is to establish an experimental basis for relationships between the main geometrical parameters that define a biplane configuration (stagger, decalage, gap, and sweep angle) and the aerodynamic characteristics (CL, CD). This experimental study focuses on a 2D approach. This method is the first step towards dealing with the issue, and it allows the variables involved in the tests to be reduced. The biplane configuration has been compared with the monoplane configuration to analyze the viability for implementing the biplane configuration in the field of application for micro air vehicles (MAV). At present, the biplane and other unusual configurations have not been a common design for MAV; however, they do have unlimited future potential. A set of experimental tests were carried out on various biplane configurations at low Reynolds numbers, which allowed the criteria for selecting the best wing configuration to be defined. The results obtained here show that the biplane configuration provides a higher maximum lift coefficient (CLmax) than the planar wing (monoplane). Furthermore, it has a larger wetted surface than the planar configuration, so the parasitic drag increases for the biplane configuration. This research is focused on a drone flight regime (low Reynolds number), and in this case, the parasitic drag (profile drag) has an important role in the total drag of the airplane. This study considers whether the reduction in the induced drag due to three–dimensional configuration (biplanes, box–wings, and joined–wings) can reduce the total drag or if the increase in the parasitic drag is bigger. Additionally, the increase in lift and the decrease in parasitic drag (profile drag) will be studied to determine if they have a greater influence on the performance of the airplane than the increase in structural weight. Further research is planned to be performed on 3D prototypes, with the selected configurations, and applied to nonconventional wing planforms.Publicación Restringido Aerodynamic Flow Effects on Aircraft Carrier Takeoff Performance(Aerospace Research Central, 2019-01-11) Rafael, Bardera Mora; 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.Publicación Acceso Abierto Impacts of Saharan Dust Intrusions on Bacterial Communities of the Low Troposphere(Springer Nature Research Journals, 2020-04-22) González-Toril, Elena; Osuna Esteban, Susana; Viúdez Moreiras, Daniel; Navarro Cid, Ivan; Díaz del Toro, Silvia; Sor, Suthyvann; Rafael, Bardera Mora; Sánchez, F. P.; De Diego Castilla, Graciela; Aguilera, Á.; Ministerio de Economía y Competitividad (MINECO); Agencia Estatal de Investigación (AEI); Sor, S. https://orcid.org/0000-0002-6972-8601We have analyzed the bacterial community of a large Saharan dust event in the Iberian Peninsula and, for the first time, we offer new insights regarding the bacterial distribution at different altitudes of the lower troposphere and the replacement of the microbial airborne structure as the dust event receeds. Samples from different open-air altitudes (surface, 100 m and 3 km), were obtained onboard the National Institute for Aerospace Technology (INTA) C-212 aircrafts. Samples were collected during dust and dust-free air masses as well two weeks after the dust event. Samples related in height or time scale seems to show more similar community composition patterns compared with unrelated samples. The most abundant bacterial species during the dust event, grouped in three different phyla: (a) Proteobacteria: Rhizobiales, Sphingomonadales, Rhodobacterales, (b) Actinobacteria: Geodermatophilaceae; (c) Firmicutes: Bacillaceae. Most of these taxa are well known for being extremely stress-resistant. After the dust intrusion, Rhizobium was the most abundant genus, (40–90% total sequences). Samples taken during the flights carried out 15 days after the dust event were much more similar to the dust event samples compared with the remaining samples. In this case, Brevundimonas, and Methylobacterium as well as Cupriavidus and Mesorizobium were the most abundant genera.
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