TY  - JOUR
AU  - Mou, Ruiyong
AU  - Huang, Xingrong
AU  - Liu, Feng
PY  - 2026
DA  - 2026/09/29
TI  - Reynolds-Number-Dependent Energy Harvesting by Freely Rotating Variable-angle Rhombic and Variable-side-length Parallelogram Cylinders
JO  - Journal of Carbon Neutrality
T2  - Journal of Carbon Neutrality
JF  - Journal of Carbon Neutrality
VL  - 1
IS  - 2
SP  - 155
EP  - 166
DO  - 10.62762/JCN.2026.692457
UR  - https://www.icck.org/article/abs/JCN.2026.692457
KW  - energy harvesting
KW  - vortex-induced rotation
KW  - immersed boundary method
KW  - variable-angle rhombic cylinder
KW  - variable-side-length parallelogram cylinder
AB  - Bluff-body flow-energy harvesters are commonly designed around translational vibration, whereas freely rotating polygonal sections provide an alternative route that harnesses rotational oscillations. In this study, Reynolds-number-dependent energy-harvesting responses of two reconfigurable sections, a variable-angle rhombic cylinder and a variable-side-length parallelogram cylinder, are investigated using an immersed boundary method. The body rotates freely about its centroid without a linear spring or external damping. Results show that at $Re=40$, decreasing the rhombus angle improves start-up and increases the bounded-oscillation amplitude, favoring oscillation-based harvesting, while the parallelogram oscillation amplitude varies non-monotonically with side-length ratio, with $\lambda=1.1$ yielding the largest bounded-oscillation amplitude. At $Re=150$, acute rhombi sustain the largest bounded oscillations, whereas the square cylinder develops autorotation and favors rotary harvesting; the parallelogram family remains on bounded oscillatory branches, with $\lambda=1.5$ producing the largest response envelope. Phase-resolved analyses reveal that periodic near-wake reorganization maintains the oscillation of acute rhombi through favorable alignment between the hydrodynamic moment and the angular velocity. These findings provide geometry-selection guidelines for oscillatory and rotary flow-energy harvesters.
SN  - 3144-2668
PB  - Institute of Central Computation and Knowledge
LA  - English
ER  - 

@article{Mou2026ReynoldsNu,
  author = {Ruiyong Mou and Xingrong Huang and Feng Liu},
  title = {Reynolds-Number-Dependent Energy Harvesting by Freely Rotating Variable-angle Rhombic and Variable-side-length Parallelogram Cylinders},
  journal = {Journal of Carbon Neutrality},
  year = {2026},
  volume = {1},
  number = {2},
  pages = {155-166},
  doi = {10.62762/JCN.2026.692457},
  url = {https://www.icck.org/article/abs/JCN.2026.692457},
  abstract = {Bluff-body flow-energy harvesters are commonly designed around translational vibration, whereas freely rotating polygonal sections provide an alternative route that harnesses rotational oscillations. In this study, Reynolds-number-dependent energy-harvesting responses of two reconfigurable sections, a variable-angle rhombic cylinder and a variable-side-length parallelogram cylinder, are investigated using an immersed boundary method. The body rotates freely about its centroid without a linear spring or external damping. Results show that at \$Re=40\$, decreasing the rhombus angle improves start-up and increases the bounded-oscillation amplitude, favoring oscillation-based harvesting, while the parallelogram oscillation amplitude varies non-monotonically with side-length ratio, with \$\lambda=1.1\$ yielding the largest bounded-oscillation amplitude. At \$Re=150\$, acute rhombi sustain the largest bounded oscillations, whereas the square cylinder develops autorotation and favors rotary harvesting; the parallelogram family remains on bounded oscillatory branches, with \$\lambda=1.5\$ producing the largest response envelope. Phase-resolved analyses reveal that periodic near-wake reorganization maintains the oscillation of acute rhombi through favorable alignment between the hydrodynamic moment and the angular velocity. These findings provide geometry-selection guidelines for oscillatory and rotary flow-energy harvesters.},
  keywords = {energy harvesting, vortex-induced rotation, immersed boundary method, variable-angle rhombic cylinder, variable-side-length parallelogram cylinder},
  issn = {3144-2668},
  publisher = {Institute of Central Computation and Knowledge}
}