Vortex transition and thermal mixing by pitching a perforated flexible panel

Fuente: arXiv
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Main Authors: Fu, Yicong, Liu, Zhengyang, Tandon, Samir, Gelfand, Jake, Jung, Sunghwan
Format: Preprint
Published: 2025
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_version_ 1866910063920152576
author Fu, Yicong
Liu, Zhengyang
Tandon, Samir
Gelfand, Jake
Jung, Sunghwan
author_facet Fu, Yicong
Liu, Zhengyang
Tandon, Samir
Gelfand, Jake
Jung, Sunghwan
contents The effective transport of heat and mass is crucial to both industrial applications and physiological processes. Recent research has evaluated the benefit of using flexible reeds for triggering the vortex induced vibration to enhance mixing, as opposed to traditional techniques like rigid blender or static meshes. Inspired by the soft, porous, and moving fish gill lamellae, we proposed a new concept of thermal dispenser that prescribes active pitching motion to the leading edge of an otherwise passively flapping perforated panel. Experimental measurements revealed drastic differences between the steady leaky flow wake behind a statically deflected perforated panel and the periodic shedding wakes with complex vortex structure transitions behind an actuated perforated panel with or without chord-wise flexibility. A semi-empirical simulation of the thermal convection and diffusion takes the experimentally obtained velocity as input and yields the temperature results. Vortex dynamics, Lagrangian coherent structures, and thermal mixing behaviors were analyzed and compared to elucidate the effects of kinematics, perforation, and flexibility on the wake mode transitions, lateral entrainment mixing, and overall heating. Our work provides a foundational understanding of the fluid-structure interactions of perforated bendable panels under active control which has not been described before in the intermediate Reynolds number range. It provides insights for developing an innovative bio-inspired heat or mass dispenser potentially suitable for subtle and small scale applications.
format Preprint
id arxiv_https___arxiv_org_abs_2504_03987
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Vortex transition and thermal mixing by pitching a perforated flexible panel
Fu, Yicong
Liu, Zhengyang
Tandon, Samir
Gelfand, Jake
Jung, Sunghwan
Fluid Dynamics
Chaotic Dynamics
Applied Physics
Biological Physics
The effective transport of heat and mass is crucial to both industrial applications and physiological processes. Recent research has evaluated the benefit of using flexible reeds for triggering the vortex induced vibration to enhance mixing, as opposed to traditional techniques like rigid blender or static meshes. Inspired by the soft, porous, and moving fish gill lamellae, we proposed a new concept of thermal dispenser that prescribes active pitching motion to the leading edge of an otherwise passively flapping perforated panel. Experimental measurements revealed drastic differences between the steady leaky flow wake behind a statically deflected perforated panel and the periodic shedding wakes with complex vortex structure transitions behind an actuated perforated panel with or without chord-wise flexibility. A semi-empirical simulation of the thermal convection and diffusion takes the experimentally obtained velocity as input and yields the temperature results. Vortex dynamics, Lagrangian coherent structures, and thermal mixing behaviors were analyzed and compared to elucidate the effects of kinematics, perforation, and flexibility on the wake mode transitions, lateral entrainment mixing, and overall heating. Our work provides a foundational understanding of the fluid-structure interactions of perforated bendable panels under active control which has not been described before in the intermediate Reynolds number range. It provides insights for developing an innovative bio-inspired heat or mass dispenser potentially suitable for subtle and small scale applications.
title Vortex transition and thermal mixing by pitching a perforated flexible panel
topic Fluid Dynamics
Chaotic Dynamics
Applied Physics
Biological Physics
url https://arxiv.org/abs/2504.03987