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- Effects of a Dynamic Leading Edge on a Plunging AirfoilPublication . Camacho, Emanuel; Neves, Fernando M. S. P.; Marques, Flávio D.; Barata, Jorge M M; Silva, AndréThe dynamics of oscillating airfoils are of great interest in many research areas such as rotor dynamics and biomimetics. The results reported in this research provide an insight into the mechanics of birds’ leading edge and how the dynamic curvature of the airfoil can highly benefit the aerodynamic and propulsive performance, especially at high angles of attack. The main goal of the current work is to numerically investigate the influence of a deflecting leading edge on the propulsive coefficients and flowfield created by a plunging airfoil at a Reynolds number of 1.4 × 104 and a constant Strouhal number of 0.15 with different ( k, ℎ) combinations. Employing a RANS approach with the proposed NACA0012-IK30 airfoil, results show that dynamically deflecting the leading edge significantly improves the propulsive efficiency of the airfoil by either reducing the required power or improving the thrust production. The outcomes regarding the propulsive efficiency show a considerable increase of up to 92% when the higher nondimensional amplitude was considered.
- Leading-Edge Parametric Study of the NACA0012-IK30 AirfoilPublication . Camacho, Emanuel; Marques, Flávio D.; Silva, A. R. R.; Barata, Jorge M MIn many research areas, such as rotor dynamics and biomimetics, the dynamics of oscillating airfoils are of great interest. The findings of this study provide great insight into the importance of the leading edge regarding the propulsive characteristics of flapping airfoils. The main objective of the present work is to analyze the influence of the leading-edge pitching amplitude of the NACA0012-IK30 airfoil at a Reynolds number of 1.4x10^4, constant Strouhal number of 0.15 with three different (k,h) combinations and five leading-edge pitching amplitudes (A_alpha=0º,5º,10º,15º,20º). Using a RANS approach with the turbulence model k-omega SST coupled with the Intermittency Transition Model, results show that changing the leading-edge pitching amplitude has great impact on thrust enhancement, although presenting a small influence when it comes to lower nondimensional amplitudes. The required power coefficient is typically reduced while increasing the leading-edge pitching amplitude which, in some cases, provides an increase up to 211% in propulsive efficiency.
- Wing Design and Analysis for Micro Air Vehicle DevelopmentPublication . Ferreira, Rúben; Camacho, Emanuel; Neves, Fernando M. S. P.; Barata, Jorge M M; Silva, AndréNatural flight was always a source of inspiration to human beings, and by observing it, new technologies emerged, especially in bioinspired aerial vehicle design. The main objective of the present work is to experimentally evaluate the influence of the wing shape on their behavior and power consumption. To accomplish that goal, four wings were selected and an experimental rig was developed. Airflow velocities tested ranged from 0 up to 4 m s−1 with four different throttle positions. Flapping frequency and amplitude were obtained from high-speed camera tests and the power consumption of the wings tested was measured. It is observed that amplitude is between 0.12 m and 0.25 m, frequency between 4 and 15 Hz. Regarding power consumption, the design wings presented lower averaged power-to-weight ratio values when compared to BionicBird wings.