TY - JOUR
T1 - On the propulsive performance of a pitching foil with chord-wise flexibility at the high Strouhal number
AU - Chao, Li Ming
AU - Pan, Guang
AU - Cao, Yong Hui
AU - Zhang, Dong
AU - Yan, Guo Xin
N1 - Publisher Copyright:
© 2018 Elsevier Ltd
PY - 2018/10
Y1 - 2018/10
N2 - During the predatory behaviour, the aquatic animals rapidly oscillate their fins to attack the preys or escape from the predators. In the light of this situation above, we experimentally investigate a chord-wise flexible foil pitching at the high Strouhal number, which is significantly larger than the previous studies almost performed at St<1. In the present work, the chord-wise flexibility of the foil has been considered as two components: the flexible length represented by the cf and the hardness of the flexible materials denoted by the Shore A hardness number. The experimental data indicates that the softer foil shows an overwhelming ability on generating efficient propulsion than the harder counterparts at smaller cf. Along with the increase of cf, the flexibility of foil shows the positive/negative influences on the foil's propulsive performance, which is closely related to the temporal evolution of the foil's shape and the effects of flexible materials on the wake structures produced by the foil. Synthetically, taking the cf and Shore A hardness number of into account, we reveal that the propulsive force of a pitching foil is relied heavily on the St, and the foil can obtain optimal propulsive efficiency when the St and the inertia of flexible section are synchronously smaller. This work is helpful for well-understanding the predatory behaviour and designing the bio-inspired underwater robotics.
AB - During the predatory behaviour, the aquatic animals rapidly oscillate their fins to attack the preys or escape from the predators. In the light of this situation above, we experimentally investigate a chord-wise flexible foil pitching at the high Strouhal number, which is significantly larger than the previous studies almost performed at St<1. In the present work, the chord-wise flexibility of the foil has been considered as two components: the flexible length represented by the cf and the hardness of the flexible materials denoted by the Shore A hardness number. The experimental data indicates that the softer foil shows an overwhelming ability on generating efficient propulsion than the harder counterparts at smaller cf. Along with the increase of cf, the flexibility of foil shows the positive/negative influences on the foil's propulsive performance, which is closely related to the temporal evolution of the foil's shape and the effects of flexible materials on the wake structures produced by the foil. Synthetically, taking the cf and Shore A hardness number of into account, we reveal that the propulsive force of a pitching foil is relied heavily on the St, and the foil can obtain optimal propulsive efficiency when the St and the inertia of flexible section are synchronously smaller. This work is helpful for well-understanding the predatory behaviour and designing the bio-inspired underwater robotics.
KW - Chord-wise flexibility
KW - High Strouhal number
KW - Pitching foil
UR - http://www.scopus.com/inward/record.url?scp=85052433601&partnerID=8YFLogxK
U2 - 10.1016/j.jfluidstructs.2018.08.007
DO - 10.1016/j.jfluidstructs.2018.08.007
M3 - 文章
AN - SCOPUS:85052433601
SN - 0889-9746
VL - 82
SP - 610
EP - 618
JO - Journal of Fluids and Structures
JF - Journal of Fluids and Structures
ER -