000			02693nam a22001577a 4500
082			_a621
100			_aMir Afzal, _9130446
245			_aExperimental Investigation of Vortex Induced Vibration Piezoelectric Energy Harvester using Dimpled Structure / _cMir Afzal
264			_aIslamabad : _bSMME- NUST; _c2025.
300			_a74p. _bSoft Copy _c30cm
500			_aThe growing demand for sustainable energy solutions for autonomous IoT sensors and remote monitoring devices has driven interest in piezoelectric energy harvesting from ambient fluid flows. This study investigates wake-induced vibrations from PVDF piezoelectric flags positioned behind dimpled circular cylinders compared to smooth baseline configurations. Comprehensive water tunnel experiments tested a 25 mm diameter cylinder at flow velocities of 0.15-0.30 m/s (Reynolds numbers 3500-11500). Nine dimpled configurations were evaluated, featuring three dimple diameters (9, 11, and 13mm) arranged in 3, 4, and 5 columns. Flag was positioned at streamwise gaps of 1D3D downstream. Data acquisition included real-time measurements of voltage, high velocity analysis of video, and Particle Image Velocimetry (PIV) for wake characterization. Smooth circular cylinders significantly outperformed all dimpled configurations and achieved peak power output of 15.2 μW at 2D spacing and 0.30 m/s, maintaining optimal wake width. Performance degraded systematically among dimpled configurations: 3-column arrangements outperformed 4-column designs, which exceeded 5-column configurations, while smaller dimples consistently outperformed larger ones. The best dimpled cylinder (3-column, 9mm dimples) achieved only 91.45% of smooth cylinder performance, while the worst configuration (5-column, 13mm dimples) delivered merely 59.41% of baseline output. PIV analysis revealed dimple-induced boundary layer energization promotes premature flow reattachment, reducing wake width and vortex formation length, thus diminishing downstream energy availability. Optimal energy harvesting occurs at 1.5D-2.5D spacing, peaking at 2D regardless of configuration. These findings provide critical design guidance for marine sensors, structural health monitoring, and autonomous underwater vehicles, demonstrating that smooth cylinders optimize VIV energy harvesting. This research advances understanding of fluid-structure interactions in energy harvesting and provides practical guidelines for sustainable micro-power generation systems.
650			_aMS Mechanical Engineering
700			_aSupervisor : DR. EMAD UD DIN _9119531
856			_uhttp://10.250.8.41:8080/xmlui/handle/123456789/54443
942			_2ddc _cTHE
999			_c614607 _d614607