Unsteady Aerodynamics of Flapping Wing of a Bird

Moelyadi, Mochammad Agoes; Putra, Hendra Adi; Sachs, Gottfried

doi:10.5614/j.eng.technol.sci.2013.45.1.4

Cited by 4 publications

(3 citation statements)

References 5 publications

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“…It reduces for higher α with higher wind speeds. Similar to the findings of Bie et al (40) , Chang et al (47) and Moelyadi et al (41) , low pressure on the upper surfaces of the wing in flight increases lift with accompanying drag. In general, increasing the angle-of-attack significantly increases lift.…”

Section: Case 3: Wrist Joint and The Effects Of Varying Wing Twistsupporting

confidence: 83%

“…The higher flapping frequency (2.5Hz) performs better than the lower frequency (1.5Hz). Moelyadi et al (41) performed flow simulations on a seagull-inspired wing under pure flapping motion and showed that the wing would be aerodynamically efficient and stable at flapping frequency of 3Hz, close to the highest and optimal frequency investigated in the present study (i.e. 2.5Hz).…”

Section: Case 1: Shoulder Joint and The Effects Of Varying The Flapping Amplitude Flapping Frequency And Stroke Ratiosupporting

confidence: 73%

“…This is how natural flyers maintain favourable values of non-dimensional parameters such as the Strouhal number and advance ratio which are derived from the flapping frequency, flapping amplitude and wind speed. Earlier studies showed that increasing the frequency would enhance both lift and thrust (36,41,(43)(44)(45)(46) . However, this study provides additional insights into the relevance of the stroke ratio with the flapping frequency, wing articulations and wind speed.…”

Section: Case 1: Shoulder Joint and The Effects Of Varying The Flapping Amplitude Flapping Frequency And Stroke Ratiomentioning

confidence: 99%

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Realisation and testing of novel fully articulated bird-inspired flapping wings for efficient and agile UAVs

et al. 2021

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Large birds have evolved an effective wing anatomy and mechanics, enabling airborne mastery of manoeuvres and endurance. For these very reasons, they are difficult to replicate and study. The aim of the present work is to achieve active wing articulations to mimic natural bird flapping towards efficient and agile Unmanned Aerial Vehicles (UAVs). The proposed design, bio-mimicking the black-headed gull, Larus ridibundus, has three active and independent servo-controlled wing joints at the shoulder, elbow and wrist to achieve complex controls. The construction of the wing is realised through a polymeric skin and carbon fibre–epoxy composite spars and ribs. The wing movements (flapping, span reduction and twisting) envelopes of the full-scale robotic gull (Robogull) are examined using the Digital Image Correlation (DIC) technique and laser displacement sensing. Its aerodynamic performance was evaluated in a wind tunnel at various flapping parameters, wind speeds and angles of attack. It is observed that a flapping amplitude of 45 $^\circ$ is more favourable than 90 $^\circ$ for generating higher lift and thrust, while also depending on the presence of span reduction, twist and wind speed. The model performs better at a flying velocity of 4m/s as compared with 8m/s. Both lift and thrust are high at a higher flapping frequency of 2.5Hz. Combined variation of the flapping frequency and stroke ratio should be considered for better aerodynamic performance. The combination of a lower stroke ratio of 0.5 with a flapping frequency of 2.5Hz generates higher lift and thrust than other combinations. Span reduction and wing twist notably and independently enhance lift and thrust, respectively. An increase in the angle-of-attack increases lift but decreases thrust. The model can also generate a significant rolling moment when set at a bank angle of 20 $^\circ$ and operated with independently controlled flapping amplitudes for the wings (45 $^\circ$ for the left wing and 90 $^\circ$ for the right wing). Based on the optimal values for the flapping amplitude (45 $^\circ$ ), flapping frequency (2.5Hz) and flying velocity (4m/s), the Strouhal number (St) of the Robogull model is 0.24, lying in the optimal range ( $0.2 < \mathrm{St} < 0.4$ ) for natural flyers and swimmers.

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Section: Case 3: Wrist Joint and The Effects Of Varying Wing Twistsupporting

confidence: 83%

Section: Case 1: Shoulder Joint and The Effects Of Varying The Flapping Amplitude Flapping Frequency And Stroke Ratiosupporting

confidence: 73%

Section: Case 1: Shoulder Joint and The Effects Of Varying The Flapping Amplitude Flapping Frequency And Stroke Ratiomentioning

confidence: 99%

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Realisation and testing of novel fully articulated bird-inspired flapping wings for efficient and agile UAVs

et al. 2021

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Aerodynamic Cost of Flapping

Sachs

2015

J Bionic Eng

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Preliminary design of bionic flapping wing vehicle

Moelyadi

Amalia

Tanoto

et al. 2021

IOP Conf. Ser.: Mater. Sci. Eng.

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This paper deals with the preliminary design of bionic flapping wing vehicle. The design is driven by its requirement and objective namely the maximum weight should be less than 0.5 kg with 1.5 m wingspan. In the conceptual design, the wing planform, wing structures and system of flapping mechanism will be considered to find the initial configuration and then continued the sizing of the flapping vehicle. The analysis of designed flapping vehicle is increasingly complex due to firstly the generation of time-dependent aerodynamic forces and moments from unsteady flow around the flapping wing, secondly, flexible wing structure which generates higher thrust may cause a structure failure and thirdly, a flapping mechanism system generating differential flapping motion for the vehicle maneuver. The aerodynamic analysis for given flapping motion model is carried out using Computational Fluid Dynamics method based the solution of unsteady Reynold Averaged Navier-Stokes equations and the structure analysis is conducted with the input of aerodynamic loads using Finite Element method to find critical stresses that may cause a structure failure. As a solution of differential flapping two controlled servos are used. The architecture of electrical system is made to analysis of the distribution of data signal and power. The flight maneuver is achieved by changes in flapping frequency and sweeping angle. The selection of system components is performed by considering weight constraint. The flight maneuver is achieved by changes in flapping frequency and sweeping angle. The wing platform has elliptical shape with airfoil maximum camber of 6% chord at a quarter chord. The outer body and wing are made of foam laminated by glass fibre with the foam density of 0.045 g/cm3. The horizontal tail is made of mylar film with density of 1.38 g/cm3 and its area of 168.3 cm2. As simulated results, the amount of total lift is 4.18 Newton generated at 6 Hz flapping frequency.

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Unsteady Aerodynamics of Flapping Wing of a Bird

Cited by 4 publications

References 5 publications

Realisation and testing of novel fully articulated bird-inspired flapping wings for efficient and agile UAVs

Realisation and testing of novel fully articulated bird-inspired flapping wings for efficient and agile UAVs

Aerodynamic Cost of Flapping

Preliminary design of bionic flapping wing vehicle

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