Biomimetic Groove and Elliptical Bluffness Synergy for Enhanced Vortex-Induced Vibration Excitation

Yunus Celik^*, Burhan Necati Kiziloglu
Department of Aeronautical Engineering, Sivas University of Science and Technology, Sivas, Turkey
* Corresponding Author: Yunus Celik. Email: email

Computer Modeling in Engineering & Sciences https://doi.org/10.32604/cmes.2026.084744

Received 28 April 2026; Accepted 22 June 2026; Published online 20 July 2026

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Abstract

This study investigates the passive amplification of aerodynamic excitation forces through coordinated bluff-body geometric modifications to quantify the vortex-induced vibration (VIV) energy harvesting potential of stationary cylinders in the laminar regime. Two-dimensional laminar simulations on fixed bodies isolate geometric effects from structural feedback. Circumferential biomimetic grooves are first optimised on a circular baseline at Re=200 using a Taguchi orthogonal array (L9), identifying groove amplitude as the dominant control parameter and selecting N=24, Amp=5% as the optimal configuration, which yields a 21% increase in the root-mean-square lift coefficient (Cℓ,rms) and a 12.5% Strouhal number reduction relative to the smooth circular baseline. The optimal groove profile is coupled with vertically-oriented bluff elliptical bases at three aspect ratios (AR=1.0, 0.75, and 0.50). Proper Orthogonal Decomposition (POD), wake fluctuation energy (WFE) mapping, and a simplified one-degree-of-freedom (1-DOF) structural projection model quantify the aerodynamic excitation power across all six configurations. Results reveal a geometric sweet spot at AR=0.75, where the Grooved configuration achieves the highest projected aerodynamic excitation power (Pest=0.5184 W/m), corresponding to a 2.24-fold amplification of the available fixed-body forcing relative to the smooth circular baseline and outperforming the aggressively bluff Grooved AR=0.50 geometry. This counter-intuitive result is attributed to groove-to-boundary-layer interaction saturation: at AR=0.50, the shortened streamwise body dimension suppresses the shear-layer tripping mechanism. POD analysis confirms high modal coherence at the optimum, with the first two modes capturing 96.2% of the total fluctuation energy, indicating forcing characteristics favourable for sustained VIV lock-in. A complementary Reynolds-number sensitivity analysis conducted at Re=100 and 150 further reveals that the groove contribution at AR=0.50 remains uniformly suppressed relative to AR=0.75 across the full laminar range, confirming that the saturation mechanism is a robust geometric feature rather than a Reynolds-specific artefact. However, the absolute geometric optimum is Reynolds-number dependent. AR=0.50 delivers stronger excitation at Re=100, the two configurations converge at Re=150, and AR=0.75 is the best-performing aspect ratio among those evaluated at Re=200, indicating the onset of the boundary-layer saturation mechanism at Re=150.