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Flying snakes are the only snakes on Earth capable of aerial gliding, taking advantage of fluid dynamic principles to leap from point to point among the trees. During their gliding, the locomotion of aerial undulation is observed. We hypothesize that this locomotion and its associated unsteady vortex dynamics are critical to their aerodynamic performance. However, there is a lack of detailed three-dimensional flow field information around the snake body in gliding due to the difficulties in experimental flow visualizations of live animals. In this study, a computation fluid dynamics (CFD) study has been conducted to study the fluid dynamics of a snake-like gliding. A mathematical equation describing the horizontal undulation motion was applied for constructing snake-like 3D computational models and a series of flow simulations were conducted. An immersed-boundary-method (IBM)-based direct numerical simulation (DNS) flow solver along with adaptive mesh refinement (AMR) was used in the simulation. Specifically, different head positions, corresponding to different horizontal wave shapes and their effect on aerodynamic performance, flow field and wake structures behind the body will be studied. In addition, the dynamic undulating motion is introduced in the model and a CFD simulation is also conducted. Results from this study are expected to bring a step stone to understanding snake-inspired locomotion.
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Material properties of skin in the flying snake Chrysopelea ornata
Abstract In snakes, the skin serves for protection, camouflage, visual signaling, locomotion, and its ability to stretch facilitates large prey ingestion. The flying snakes of the genusChrysopeleaare capable of jumping and gliding through the air, requiring additional functional demands: its skin must accommodate stretch in multiple directions during gliding and, perhaps more importantly, during high‐speed, direct‐impact landing. Is the skin of flying snakes specialized for gliding? Here, we characterized the material properties of the skin ofChrysopelea ornataand compared them with two nongliding species of colubrid snakes,Thamnophis sirtalisandPantherophis guttatus, as well as with previously published values. The skin was examined using uniaxial tensile testing to measure stresses, and digital image correlation methods to determine strains, yielding metrics of strength, elastic modulus, strain energy, and extensibility. To test for loading orientation effects, specimens were tested from three orientations relative to the snake's long axis: lateral, circumferential, and ventral. Specimens were taken from two regions of the body, pre‐ and pos‐tpyloric, to test for regional effects related to the ingestion of large prey. In comparison withT. sirtalisandP. guttatus,C. ornataexhibited higher post‐pyloric and lower pre‐pyloric extensibility in circumferential specimens. However, overall there were few differences in skin material properties ofC. ornatacompared to other species, both within and across studies, suggesting that the skin of flying snakes is not specialized for gliding locomotion. Surprisingly, circumferential specimens demonstrated lower strength and extensibility in pre‐pyloric skin, suggesting less regional specialization related to large prey.
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- Award ID(s):
- 2027523
- PAR ID:
- 10399455
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Journal of Experimental Zoology Part A: Ecological and Integrative Physiology
- Volume:
- 339
- Issue:
- 3
- ISSN:
- 2471-5638
- Format(s):
- Medium: X Size: p. 269-283
- Size(s):
- p. 269-283
- Sponsoring Org:
- National Science Foundation
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