Journal
JOURNAL OF FLUID MECHANICS
Volume 859, Issue -, Pages 921-948Publisher
CAMBRIDGE UNIV PRESS
DOI: 10.1017/jfm.2018.833
Keywords
aerodynamics; biological fluid dynamics; swimming; flying
Categories
Funding
- Australian Research Council [DP150102879]
- Monash Graduate Scholarship (MGS)
- Monash International Postgraduate Research Scholarship (MIPRS)
- National Computational Infrastructure (NCI) [d71]
Ask authors/readers for more resources
The individual and combined influences of aspect ratio ( A), Reynolds number (Re) and Rossby number (Ro) on the leading-edge vortex (LEV) of a rotating wing of insect-like planform are investigated numerically. A previous study from our group has determined the wingspan to be an appropriate length scale governing the large-scale LEV structure. In this study, the A range considered is further extended, to show that this scaling works well as A is varied by a factor of 4 (1:8 6A6 7:28) and over a Re range of two orders of magnitude. The present study also extends this scaling for wings with an offset from the rotation axis, which is typically the case for actual insects and often for experiments. Remarkably, the optimum range of A based on the lift coefficients at different Re coincides with that observed in nature. The scaling based on the wingspan is extended to the acceleration terms of the Navier-Stokes equations, suggesting a modified scaling of Ro, which decouples the effects of A. A detailed investigation of the flow structures, by increasing Ro in a wide range, reveals the weakening of the LEV due to the reduced spanwise flow, resulting in a reduced lift. Overall, the use of span-based scaling of Re and Ro, together with A, may help reconcile apparent conflicting trends between observed variations in aerodynamic performance in different sets of experiments and simulations.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available