A piezoelectric wind-induced vibration energy harvester via the Venturi effect

Applied Physics Letters, Journal Year: 2025, Volume and Issue: 126(7)

Published: Feb. 17, 2025

In this Letter, the Venturi effect is introduced to change vibration behaviors of a downwind bluff body and piezoelectric wind-induced energy harvester using (VE-PWVEH) reported offer an alternative solution enable high-performance PWVEH. Also, power generation characteristics were readily adjusted by flow channel forming without modifying PWVEH structure. So, VE-PWVEH could possess both great power-generating capability at low wind speed strong robustness high speed. The results demonstrated that output voltage cut-in affected attack angle two rectangular plates used for stimulating constricted channel. There was optimal 60° where maximum peak increased 621% reduced 171% compared with effect. Besides, it achieve 0.863 mW illuminate about 120 blue LEDs in series. introduction provides simple viable method field disturbance tune performance PWVEHs.

Language: Английский

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A wind-direction adaptive piezoelectric energy harvester employing small wing passive control configuration

Applied Physics Letters, Journal Year: 2024, Volume and Issue: 124(23)

Published: June 3, 2024

In this study, we propose a wind-direction adaptive piezoelectric energy harvester employing small wing passive control configuration (WDEH-SW) for bidirectional wind harvesting. Our design significantly enhances harvesting capabilities, addressing the limitations of traditional harvesters by modifying aerodynamic characteristics bluff body via rotations. Additionally, introduce criterion determining impact direction changes on efficiency. Experimental comparisons with conventional galloping-based and vortex-induced vibration-based demonstrate superior performance proposed structure. The experiment results indicate that structure effectively adapts to in direction, thereby preventing significant decrease or failure Compared unidirectional harvester, exhibits 34.6% increase 1.63 μW power output, an overall average output reaching 6.35 μW. Notably, WDEH-SW shows excellent adaptability high both medium low velocity ranges, providing valuable insights designing compact harvesters. This study showcases promising applications self-powered micro-devices, particularly straightforward environments such as car train tunnel entrances exits.

Language: Английский

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Aeroacoustic simulation of bluff bodies with protrusions at moderate Reynolds number

Physics of Fluids, Journal Year: 2024, Volume and Issue: 36(2)

Published: Feb. 1, 2024

This paper presents an evaluation of passive control methods that employ surface protrusions to mitigate the aerodynamic sound generated from a cylinder wake flow. Building on previous designs optimized for low Reynolds numbers (Re = 150) through adjoint-based aeroacoustic shape optimization, this study investigated performance under moderate number 67 000) condition typical mechanical engineering applications using simulations based lattice Boltzmann method. Three configurations were tested, all which found significantly reduce mean drag by at least 45% compared with unmodified circular cylinder. Designs featuring rear outperformed conventional splitter plate in terms reduction performance, symmetrical both front and surfaces achieving tonal 13 dB. However, specific protrusion design increased low-frequency owing intensified large-scale flow separation. These findings highlight effectiveness suppressing oscillations dipole generation subcritical range. Moreover, revealed need tailor optimization.

Language: Английский

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Sources and mechanisms of flow loss and hydroacoustics in a pre-swirl stator pump-jet propulsor

Physics of Fluids, Journal Year: 2024, Volume and Issue: 36(2)

Published: Feb. 1, 2024

Accurately identifying sources of flow loss and hydroacoustics clarifying the mechanism their generation are crucial for directing optimal design efficient quiet pump-jet propulsors (PJPs). In this paper, numerical simulations steady unsteady performed a PJP equipped with pre-swirl stationary vanes, based on which both investigated at multi-level granularity. Analyses efficiency entropy rate to identify loss, analyses thrust fluctuation wall pressure conduced hydroacoustics. The results indicate that drag accounts 76% total is mainly contributed from stator duct, but rotor much smaller than located three regions rotating blades: leading edge, tip, corner suction surface. hydroacoustic edge tip blades due stator–rotor duct–rotor interactions, respectively, Taylor's frozen turbulence hypothesis inappropriate describe wake evolution vanes owing potential interaction caused by blade rotation.

Language: Английский

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Aeroacoustic investigation of a ducted wind turbine employing bio-inspired airfoil profiles

Physics of Fluids, Journal Year: 2024, Volume and Issue: 36(4)

Published: April 1, 2024

Ducted wind turbines for residential purposes are characterized by a lower diameter with respect to conventional on-shore applications. The noise generated the rotor plays significant role in overall aerodynamic noise. By making modifications blade sections of turbine, we can alter contributions aeroacoustic sources. This study introduces innovative turbine designs inspired owl wing characteristics, achieving reduction without compromising performance. A three-dimensional scan an was first employed derive family airfoils. airfoils were modify referenced airfoil section at various positions on span determine operating more efficiently tip-speed ratio original one. While maintaining same performance, bio-inspired profiles show uniform pressure coefficient distribution, considerably decreasing level. Furthermore, this makes considerable progress ducted design obtaining 8 dB and 12% improvement sound An in-depth examination shows 6.4% rise thrust force optimized power coefficients, reaching peak tip speed 8, demonstrating improved energy conversion efficiency. results highlight dual advantage design: enhanced efficiency, offering promising alternative urban generation.

Language: Английский

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Flow and noise control of a cylinder using grooves filled with porous material

Physics of Fluids, Journal Year: 2024, Volume and Issue: 36(4)

Published: April 1, 2024

In the present numerical study, we propose a new passive flow control mechanism at Reynolds number of 3900. The novel method benefits from making grooves in cylinder wall while are filled with porous materials specific permeability. According to literature survey, medium is potentially an effective noise method, it has serious drawbacks, mainly significant pressure drop. instead coating, fillers introduced offering substantial reduction level, addition managing hydrodynamic parameters. To find suitable design for and fillers, systematic parametric study performed on number, sequence size grooves, as well fillers' permeabilities. Based results, newly proposed dominated traditional full coating by limiting turbulent kinetic energy (TKE). results indicated that angle 90° relative front stagnation point reduced overall sound level (OASPL) 1.25 dB; meanwhile, high-intensity TKE region shrunk. Further reductions were achieved deeper drag coefficient, lift Strouhal OASPL up 40.2%, 27.4%, 10.6%, 3 dB, respectively. will be helpful various industrial applications cylinders through rigorous aerodynamic parameters level.

Language: Английский

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A novel passive flow control technique using circular arcs coupled with downstream splitters

Ocean Engineering, Journal Year: 2024, Volume and Issue: 313, P. 119393 - 119393

Published: Sept. 30, 2024

Language: Английский

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Numerical Prediction of Fluid Flow Noise with a Hybrid CFD-Acoustics Approach

SAE technical papers on CD-ROM/SAE technical paper series, Journal Year: 2025, Volume and Issue: 1

Published: May 5, 2025

<div class="section abstract"><div class="htmlview paragraph">This paper presents a fully parallelized Computational Acoustics (CA) module, integrated within the Simerics-MP+ platform, developed for prediction of noise source power and far-field propagation across range Fluid Dynamics (CFD) applications. Utilizing Ffowcs Williams-Hawkings (FWH) acoustic analogy, CA module seamlessly integrates with existing CFD workflows, offering minimal computational overhead less than 5% increase in runtime. Extensive validation has been conducted against analytical, numerical, experimental data various scenarios, including monopole dipole emissions, flow around slender bodies, circular cylinders aero-propellers. These studies underscore reliability framework accurately identifying sources assessing impact design modifications, significantly reducing need expensive physical prototyping industries such as automotive aerospace.</div><div paragraph">Building upon these foundational capabilities, study extends application to challenging task simulation axial fans, commonly employed HVAC systems, components, industrial processes. Given proximity fans human operators, control is critical, necessitating compliance stringent regulatory standards. In low-Mach-number aerodynamic fluctuations complex interactions are key contributors emissions. By combining Wall-Modeled Large Eddy Simulation (LES) FWH approach second-order finite volume simulates European Association (EAA) benchmark case ducted fan rates. Validation shows good agreement, demonstrating effectiveness this facilitating virtual testing. This methodology enables engineers implement mitigation strategies early process, development costs enhancing overall system performance.</div></div>

Language: Английский

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Performance improvement and noise reduction analysis of multi-blade centrifugal fan imitating long-eared owl wing surface

Physics of Fluids, Journal Year: 2023, Volume and Issue: 35(12)

Published: Dec. 1, 2023

This research was inspired by the long-eared owl's ability to fly silently. For first time in this study, a wind turbine blade is designed mimic wing surface and leading edge of owl. The commonly used two-dimensional profile previous studies replaced more effective three-dimensional profile. change leads improved aerodynamic performance multi-blade centrifugal fan reduced noise levels. airfoil parameters owl were extracted utilized. These develop fitting formula based on their correlation. facilitated design optimization bionic (B-Blade). results indicate 4.1% enhancement maximum flow rate compared original fan, alongside reduction 1.3 dB(A) under identical static pressure conditions. An examination internal flow, noise, sound source characteristics both types conducted, elucidating mechanism. Fan propagation showed pronounced dipole traits. area at B-Blade fan's inlet volute tongue compact, decrease mid-low frequency discrete noise. intensity also diminished. ameliorated distribution impeller outlet, reducing unstable interaction between tongue, thereby effectively diminishing

Language: Английский

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Symmetry-breaking response of a flexible splitter plate attached to a circular cylinder in uniform flow

Physics of Fluids, Journal Year: 2023, Volume and Issue: 35(12)

Published: Dec. 1, 2023

Static and dynamic fluid–structure interaction of a flexible plate behind stationary cylinder in uniform flow is explored for body-to-fluid mass ratio 10. Steady flow-structure computations Re = 150, based on the diameter free-stream speed, reveal four regimes with respect to increasing flexibility plate. The does not undergo any lateral deflection regime 1 beyond which it undergoes symmetry-breaking bifurcation causing spontaneously deflect laterally. curvature same sign along entire length 2 while changes 3. deflection, however, still maximum at tip. location moves away from tip 4. evolution structures including strength various standing vortices, flexibility, studied. role reattachment surface modification pressure distribution explored. critical Re, splitter achieves deflected shape, decreases increase flexibility. It estimated be 122.33 limiting case an infinitely Computations several lock-in different natural vibration modes related hysteresis. No bias time-averaged found during lock-in; occurs desynchronization that precedes second mode. For considered, static simulations start

Language: Английский

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