Aerodynamic effects of deviating motion of flapping wings in hovering flight.

Bioinspir Biomim

Department of Aerospace Engineering, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon, Republic of Korea.

Published: February 2019

Nature's flyers adopt deviating motion when they fly, however, the effect of deviating motion on the aerodynamics of flapping wings is not yet clearly understood. In this study, the aerodynamic characteristics of figure-of-eight deviating motion were investigated by comparing the aerodynamic force obtained from an experiment and the quasi-steady (QS) model in wide ranges of both the pitch and deviation amplitude. A flapping-wing robotic manipulator with a one-ton water tank was used in the experiment. Digital particle image velocimetry (DPIV) was also conducted in several chordwise cross-sections and different time instants. The results showed that the increment of deviating angle dramatically reduced the aerodynamic lift in the middle of the up- or downstroke from the quasi-steady estimation. The DPIV showed a vortex loop, which inhibits lift generation, at the middle of the up- or downstroke in deviating motion. The deviating motion delayed a development of the vortices, and more stroke angle was necessary for trailing edge vortex shedding. The QS model could not properly predict the aerodynamic force of the flapping wing with significant deviation angles. The error between the experiments and the QS estimation with regard to the aerodynamic lift was as high as 35% in the middle of the up- or downstroke with a high deviation amplitude ([Formula: see text]), reducing the cycle-averaged value of the lift coefficient up to 30%.

Download full-text PDF

Source
http://dx.doi.org/10.1088/1748-3190/aafc4dDOI Listing

Publication Analysis

Top Keywords

deviating motion
24
middle up-
12
up- downstroke
12
flapping wings
8
aerodynamic force
8
deviation amplitude
8
aerodynamic lift
8
deviating
7
aerodynamic
6
motion
6

Similar Publications

Multiple Sclerosis (MS) is an autoimmune and chronic disease in the brain and spinal cord. MS has inflammatory progression characterized by its hallmark inflammatory plaques. The histological and clinical characteristics of MS are shared by Experimental Autoimmune Encephalomyelitis (EAE).

View Article and Find Full Text PDF

Introduction: Prostate motion during external beam radiotherapy (EBRT) is common and typically managed using fiducial markers and cone beam CT (CBCT) scans for inter-fractional motion correction. However, real-time intra-fractional motion management is less commonly implemented. This study evaluated the extent of intra-fractional prostate motion using transperineal ultrasound (TPUS) and examined the impact of treatment time on prostate motion.

View Article and Find Full Text PDF

Effect of induced extrinsic and intrinsic hand and forearm muscular fatigue on the control of finger force during piano playing.

Hum Mov Sci

January 2025

Department of Biomedical Engineering, College of Engineering, National Cheng Kung University, Tainan, Taiwan; Institute of Allied Health Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan; Medical Device Innovation Center, National Cheng Kung University, Tainan, Taiwan; Department of Occupational Therapy, College of Medicine, National Cheng Kung University, Tainan, Taiwan. Electronic address:

This study aimed to investigate the effect of hand muscle fatigue on finger control and force efficiency during piano performance, which is crucial for skilled piano playing among professional pianists engaged in prolonged periods of high-intensity practice or concert preparation. Thirty-one professional pianists were recruited as participants. This study was divided into three sequential experimental parts: pre-fatigue test, fatigue protocol, and post-fatigue test.

View Article and Find Full Text PDF

Measuring lower extremity impact acceleration is a common strategy to identify runners with increased injury risk. However, existing axial peak tibial acceleration (PTA) thresholds for determining high-impact runners typically rely on small samples or fixed running speeds. This study aimed to describe the distribution of axial PTA among runners at their preferred running speed, determine an appropriate adjustment for investigating impact magnitude at different speeds, and compare biomechanics between runners classified by impact magnitude.

View Article and Find Full Text PDF

Background: The financial and resource burden of management of olecranon fractures in the elderly is likely to increase with an aging population. There is limited evidence guiding treatment choice in this cohort. This study aimed to determine whether operative treatment of displaced olecranon fractures in elderly patients provides superior 12-month functional outcomes compared to nonoperative treatment.

View Article and Find Full Text PDF

Want AI Summaries of new PubMed Abstracts delivered to your In-box?

Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!