TY  - EJOU
AU  - Celik, Yunus 
AU  - Kiziloglu, Burhan Necati 

TI  - Biomimetic Groove and Elliptical Bluffness Synergy for Enhanced Vortex-Induced Vibration Excitation
T2  - Computer Modeling in Engineering \& Sciences

PY  - 
VL  - 
IS  - 
SN  - 1526-1506

AB  - 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 <mml:math id="mml-ieqn-1"><mml:mrow><mml:mi mathvariant="normal">R</mml:mi><mml:mi mathvariant="normal">e</mml:mi></mml:mrow><mml:mo>=</mml:mo><mml:mn>200</mml:mn></mml:math> using a Taguchi orthogonal array (L9), identifying groove amplitude as the dominant control parameter and selecting <mml:math id="mml-ieqn-2"><mml:mi>N</mml:mi><mml:mo>=</mml:mo><mml:mn>24</mml:mn></mml:math>, <mml:math id="mml-ieqn-3"><mml:mi>A</mml:mi><mml:mi>m</mml:mi><mml:mi>p</mml:mi><mml:mo>=</mml:mo><mml:mn>5</mml:mn><mml:mi mathvariant="normal">%</mml:mi></mml:math> as the optimal configuration, which yields a <mml:math id="mml-ieqn-4"><mml:mn>21</mml:mn><mml:mi mathvariant="normal">%</mml:mi></mml:math> increase in the root-mean-square lift coefficient (<mml:math id="mml-ieqn-5"><mml:msub><mml:mi>C</mml:mi><mml:mrow><mml:mi>ℓ</mml:mi><mml:mo>,</mml:mo><mml:mrow><mml:mi mathvariant="normal">r</mml:mi><mml:mi mathvariant="normal">m</mml:mi><mml:mi mathvariant="normal">s</mml:mi></mml:mrow></mml:mrow></mml:msub></mml:math>) and a <mml:math id="mml-ieqn-6"><mml:mn>12.5</mml:mn><mml:mi mathvariant="normal">%</mml:mi></mml:math> 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 (<mml:math id="mml-ieqn-7"><mml:mi>A</mml:mi><mml:mi>R</mml:mi><mml:mo>=</mml:mo><mml:mn>1.0</mml:mn></mml:math>, <mml:math id="mml-ieqn-8"><mml:mn>0.75</mml:mn></mml:math>, and <mml:math id="mml-ieqn-9"><mml:mn>0.50</mml:mn></mml:math>). 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 <mml:math id="mml-ieqn-10"><mml:mi>A</mml:mi><mml:mi>R</mml:mi><mml:mo>=</mml:mo><mml:mn>0.75</mml:mn></mml:math>, where the Grooved configuration achieves the highest projected aerodynamic excitation power (<mml:math id="mml-ieqn-11"><mml:msub><mml:mi>P</mml:mi><mml:mrow><mml:mtext>est</mml:mtext></mml:mrow></mml:msub><mml:mo>=</mml:mo><mml:mn>0.5184</mml:mn></mml:math> 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 <mml:math id="mml-ieqn-12"><mml:mi>A</mml:mi><mml:mi>R</mml:mi><mml:mo>=</mml:mo><mml:mn>0.50</mml:mn></mml:math> geometry. This counter-intuitive result is attributed to groove-to-boundary-layer interaction saturation: at <mml:math id="mml-ieqn-13"><mml:mi>A</mml:mi><mml:mi>R</mml:mi><mml:mo>=</mml:mo><mml:mn>0.50</mml:mn></mml:math>, 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 <mml:math id="mml-ieqn-14"><mml:mn>96.2</mml:mn><mml:mi mathvariant="normal">%</mml:mi></mml:math> of the total fluctuation energy, indicating forcing characteristics favourable for sustained VIV lock-in. A complementary Reynolds-number sensitivity analysis conducted at <mml:math id="mml-ieqn-15"><mml:mrow><mml:mi mathvariant="normal">R</mml:mi><mml:mi mathvariant="normal">e</mml:mi></mml:mrow><mml:mo>=</mml:mo><mml:mn>100</mml:mn></mml:math> and <mml:math id="mml-ieqn-16"><mml:mn>150</mml:mn></mml:math> further reveals that the groove contribution at <mml:math id="mml-ieqn-17"><mml:mi>A</mml:mi><mml:mi>R</mml:mi><mml:mo>=</mml:mo><mml:mn>0.50</mml:mn></mml:math> remains uniformly suppressed relative to <mml:math id="mml-ieqn-18"><mml:mi>A</mml:mi><mml:mi>R</mml:mi><mml:mo>=</mml:mo><mml:mn>0.75</mml:mn></mml:math> 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. <mml:math id="mml-ieqn-19"><mml:mi>A</mml:mi><mml:mi>R</mml:mi><mml:mo>=</mml:mo><mml:mn>0.50</mml:mn></mml:math> delivers stronger excitation at <mml:math id="mml-ieqn-20"><mml:mrow><mml:mi mathvariant="normal">R</mml:mi><mml:mi mathvariant="normal">e</mml:mi></mml:mrow><mml:mo>=</mml:mo><mml:mn>100</mml:mn></mml:math>, the two configurations converge at <mml:math id="mml-ieqn-21"><mml:mrow><mml:mi mathvariant="normal">R</mml:mi><mml:mi mathvariant="normal">e</mml:mi></mml:mrow><mml:mo>=</mml:mo><mml:mn>150</mml:mn></mml:math>, and <mml:math id="mml-ieqn-22"><mml:mi>A</mml:mi><mml:mi>R</mml:mi><mml:mo>=</mml:mo><mml:mn>0.75</mml:mn></mml:math> is the best-performing aspect ratio among those evaluated at <mml:math id="mml-ieqn-23"><mml:mrow><mml:mi mathvariant="normal">R</mml:mi><mml:mi mathvariant="normal">e</mml:mi></mml:mrow><mml:mo>=</mml:mo><mml:mn>200</mml:mn></mml:math>, indicating the onset of the boundary-layer saturation mechanism at <mml:math id="mml-ieqn-24"><mml:mrow><mml:mi mathvariant="normal">R</mml:mi><mml:mi mathvariant="normal">e</mml:mi></mml:mrow><mml:mo>=</mml:mo><mml:mn>150</mml:mn></mml:math>.
KW  - Vortex-induced vibration; biomimetic surface grooves; elliptical cylinder; wake aerodynamics; Taguchi optimization; CFD

DO  - 10.32604/cmes.2026.084744