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Insects rely on their olfactory systems to detect odors and locate odor sources through highly efficient flapping-wing mechanisms. While previous studies on bio-inspired unsteady flows have primarily examined the aerodynamic functions of flapping wings, they have largely overlooked the effects of wing-induced unsteady flows on airborne odor stimuli. This study aims to explore how flapping kinematics influence odorant transport. Computational fluid dynamics simulations were employed to investigate unsteady flow fields and odorant transport by solving the Navier–Stokes and odor advection–diffusion equations. Both two-dimensional (2D) and three-dimensional (3D) simulations were conducted to visualize the flow fields and odor concentration distributions generated by pitching–plunging airfoils. Our findings reveal that higher Strouhal numbers, characterized by increased flapping frequency, produce stronger flow jets that enhance odor advection and dissipation downstream, while reducing odor concentration on the airfoil surface. In 2D simulations, symmetry breaking at high Strouhal numbers causes oblique advection of vortices and odor plumes. In contrast, 3D simulations exhibit bifurcated horseshoe-like vortex rings and corresponding odor plume bifurcations. These findings highlight the intricate coupling between unsteady aerodynamics and odor transport, offering valuable insights for bio-inspired designs and advanced olfactory navigation systems.
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This content will become publicly available on November 1, 2025
How does vortex dynamics help undulating bodies spread odor?
In this paper, we examine the coupling between odor dynamics and vortex dynamics around undulating bodies, with a focus on bio-inspired propulsion mechanisms. Utilizing computational fluid dynamics simulations with an in-house immersed boundary method solver, we investigate how different waveform patterns, specifically carangiform and anguilliform, influence the dispersion of chemical cues in both water and air environments. Our findings reveal that vortex dynamics significantly impact the overall trajectory of odor spots, although the alignment between odor spots and coherent flow structures is not always precise. We also evaluate the relative contributions of diffusion and convection in odor transport, showing that convection dominates in water, driven by higher Schmidt numbers, while diffusion plays a more prominent role alongside convection in air. Additionally, the anguilliform waveform generally produces stronger and farther-reaching chemical cues compared to carangiform swimmers. The critical roles of Strouhal number and Reynolds number in determining the efficiency of odor dispersion are also explained, offering insights that could enhance the design of more efficient, adaptive, and intelligent autonomous underwater vehicles by integrating sensory and hydrodynamic principles inspired by fish locomotion.
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- Award ID(s):
- 2453175
- PAR ID:
- 10560841
- Publisher / Repository:
- AIP Publishing
- Date Published:
- Journal Name:
- Physics of Fluids
- Volume:
- 36
- Issue:
- 11
- ISSN:
- 1070-6631
- Page Range / eLocation ID:
- 111916
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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