Mohd Nasir, Mohd Nazri (2017)
Dynamics of high-speed-resolved wing and body kinematics of freely flying houseflies responding to directed and undirected air turbulence.
Technische Universität Darmstadt
Ph.D. Thesis, Primary publication
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Item Type: | Ph.D. Thesis | ||||
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Type of entry: | Primary publication | ||||
Title: | Dynamics of high-speed-resolved wing and body kinematics of freely flying houseflies responding to directed and undirected air turbulence | ||||
Language: | English | ||||
Referees: | Cameron, Prof. Dr. Tropea ; Fritz-Olaf, Prof. Dr. Lehmann | ||||
Date: | 10 January 2017 | ||||
Place of Publication: | Darmstadt | ||||
Date of oral examination: | 10 January 2017 | ||||
Abstract: | From tiny flies to huge dragonflies, aerial locomotion of insects requires sophisticated biological control strategies and unusual aerodynamic mechanisms. During flight, unpredictable changes of ambient air flow may destabilize body posture and control owing to changes in aerodynamic force production. Pioneering discoveries demonstrated that insects such as flies actively regulate body appendages such as wings, legs and the abdomen to encounter aerial perturbations. To quantify this behaviour, I thus investigated how housefly Musca domestica behaved in response to undirected, turbulent air flows and directed impulsive wind gusts. To evaluate theoretical predictions, I three-dimensionally reconstructed body and wing motion using time-resolved high-speed videography and stimulated the freely flying animals under laboratory conditions. Impairments of mechanosensory receptors functionality allowed me to distinguish between active and passive behavioural responses and to investigate the role of sensory feedback for flight control during perturbations. The results show that houseflies typically do not take-off when mean air velocity exceed ~0.63ms-1, which compares to ~2% relative turbulence intensity. In still air, flies take-off immediately after releasing them and respond to impulsive wind gusts by uniform changes in body posture. The directional dependency of these changes is explained by a numerical aerodynamic based on quasi-steady considerations of interaction between wind gust, body and wing velocities. Shortest behavioural response delays were measured during anterior perturbation, amounting to 2.4ms (yaw axis), 5ms (roll axis) and 7.3ms (pitch axis). Under this condition, flies showed the shortest alteration period of 8ms (pitch), 13ms (roll) and 17.5ms (yaw) compared to other direction of perturbations. Body roll angle changes more strongly (18.5 fold increase) than yaw (7-fold increase) and pitch (6.4-fold increase) in response to gusts, suggesting that roll stability is most sensitive. Houseflies also actively modulate the wing kinematics to recover from aerial perturbations. In response to anterior perturbation, flies reduce mean wingbeat amplitude by ~25%, mean wing elevation angle by ~29% compared to non-perturbated controls. Approximately ~2.5 stroke cycles (~15ms) after perturbation onset, mean wingtip velocity hit the minimum of 3ms-1 and flies dynamically soars with little wing movement for 1 stroke cycles within the air stream. While responding to the gust, wing angle of attacks decreases during downstroke by ~45.5% (~60.5° at t=13.5ms) that leads to a decrease in the lift coefficient. This stabilizes lift and body position in vertical axis. During upstroke, by contrast, wing angle of attacks increases 1 fold (~-0.5° at t=12ms) compared to non perturbated controls (63±5.4°), which elevates aerodynamic drag on the flapping wings. Owing to the horizontal stroke plane, the latter change augments thrust, propelling forward and compensating for gust-induced forces. The measured response times suggest that the changes in wing kinematics cannot be explained by sensory feedback from the antennae because delays of antennae and vision mediated feedback are higher than the measured ones. This suggests that posture stabilization reflexes in flies likely results from feedback mediated by the fly’s gyroscopic halteres, signalling postural changes within ~6.7ms (a single wing stroke cycle). This thesis extends our current knowledge on insect free flight control during aerial perturbations by quantifying kinematics and behavioural response delays in houseflies. Collectively, the study provides time-resolved kinematic data on how flies cope with turbulent and wind gust. Our research delivers a contribution to the answer of the question on how insects achieve their superior flight performance. The presented data on the housefly complement recent studies in other species of flying insects and the findings are also useful in a wide scientific context. The biological flight control strategies may be transferred to the biomimetic, miniaturized micro aerial vehicles propelled by flapping wing motion. |
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URN: | urn:nbn:de:tuda-tuprints-59190 | ||||
Classification DDC: | 600 Technology, medicine, applied sciences > 620 Engineering and machine engineering | ||||
Divisions: | 16 Department of Mechanical Engineering 16 Department of Mechanical Engineering > Fluid Dynamics (fdy) 16 Department of Mechanical Engineering > Fluid Dynamics (fdy) > Strömungsmechanische Modellentwicklung |
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Date Deposited: | 13 Jan 2017 11:10 | ||||
Last Modified: | 28 Jul 2020 09:30 | ||||
URI: | https://tuprints.ulb.tu-darmstadt.de/id/eprint/5919 | ||||
PPN: | 398417423 | ||||
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