Karman Vortex Creation Using Cylinder for Flutter Energy Harvester Device

Atrah, Ahmed B.; Ab-Rahman, Mohammad Syuhaimi; Salleh, Hanim; Nuawi, Mohd. Zaki; Nor, Mohd Jailani Mohd; Jamaludin, Nordin

doi:10.3390/mi8070227

Cited by 11 publications

(13 citation statements)

References 28 publications

(34 reference statements)

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“…The flow was less disturbed by vegetation before it entered the vegetation section, and the RSN presented obvious increases after entering the vegetation section; thus, the RSNs in the vegetation section increased as the vegetation density increased. Particularly, the RSNs in the last vegetation section were 2.5 times larger than that of the non-vegetation section, which may be caused by the horseshoe vortex [59] and the karman vortex [60] generated by the impediment of the vegetation stem. The presence of these vortices would successively cause the rise of turbulent kinetic energy [61].…”

Section: Reynolds Stress Numbermentioning

confidence: 92%

Experimental Study of Overland Flow through Rigid Emergent Vegetation with Different Densities and Location Arrangements

Wang

Zhang

Yang

et al. 2018

Water

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The effect of vegetation density on overland flow dynamics has been extensively studied, yet fewer investigations have focused on vegetation arrangements with different densities and position features. Flume experiments were conducted to investigate the hydrodynamics of flow through rigid emergent vegetation arranged in combinations with three densities (Dense, Middle, and Sparse) and three positions (summit, backslope, and footslope). This study focused on how spatial variations regulated hydrodynamic parameters from two dimensions: direction along the slope and water depth. The total hydrodynamic parameters of bare slopes were significantly different from those of vegetated slopes. The relationship between Re and f illustrated that Re was not a unique predictor of hydraulic roughness on vegetated slopes. In the slope direction, all hydrodynamic parameters on vegetated slopes exhibited fluctuating downward/upward trends due to the clocking effect before the vegetated area and the rapid conveyance effect in the vegetated area, whereas constant values were observed on bare slopes. The performance of hydrodynamics parameters suggested that the dense rearward arrangement (SMD) was the optimal vegetation pattern to regulate flow conditions. Specifically, the vertical profiles of the velocity and turbulence features of the SMD arrangement at different sections demonstrated the significant role of vegetation density in identifying the velocity layers along the water depth. The maximum velocity and Reynolds Stress Number (RSN) indicated the position where local scour was most likely to occur, which would improve our basic understanding of the mechanisms underlying hydraulic and soil erosion processes.Thus, determining the optimum conditions for flow within vegetated slopes is vital for water and soil conservation and control.To understand the mechanisms underlying the hydraulic and soil erosion processes on vegetated hillslopes, hydrodynamic characteristics, which were mainly quantified by hydraulic parameters, e.g., water depth, mean velocity, flow pattern and resistance, kinetic energy and momentum distributions were considered as fundamental variables [6,7]. The hydrodynamic effects of emergent vegetation have been widely investigated in controlled laboratory experiments. In previous studies, well-defined rigid cylinder rods were assumed to represent an appropriate model for groups and trees or reeds and to generate accurate representations of the geometric characteristics [8]; thus, this method has been utilized as vegetation stems in numerous laboratory studies [7]. Generally, vegetation promotes the water depth [9], slows down the flow [10,11], enhances flow resistance [12], raises energy and momentum coefficients [13], attenuates the turbulence intensity [14], and promotes diffusion and deposition processes [15]. Dunkerley et al. [16] pointed out that plants could stabilize the flow state as laminar flow, whereas Hamilton et al. [17] stated that mixed flow states occurred on vegetated slopes. The definition of t...

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Section: Reynolds Stress Numbermentioning

confidence: 92%

Experimental Study of Overland Flow through Rigid Emergent Vegetation with Different Densities and Location Arrangements

Wang

Zhang

Yang

et al. 2018

Water

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“…By altering the design and mass of magnet, the device can be tuned as desired (Ahmad and Khan, 2018). Atrah et al (2017) mentioned that by adding a cylinder in front of the wind belt, Karmen vortex can be created to improve the wind belt performance. Materials, dimensions, tension of the wind belt are some design parameters that might affect performance.…”

Section: Wind Belt-based Approachmentioning

confidence: 99%

Design and performance evaluation of vertical axis wind turbine for wind energy harvesting at railway

Thadani

Zaaba

Shahrizal

et al. 2021

WJSTSD

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PurposeThis paper aims to design an optimum vertical axis wind turbine (VAWT) and assess its techno-economic performance for wind energy harvesting at high-speed railway in Malaysia.Design/methodology/approachThis project adopted AutoCAD and ANSYS modeling tools to design and optimize the blade of the turbine. The site selected has a railway of 30 km with six stops. The vertical turbines are placed 1 m apart from each other considering the optimum tip speed ratio. The power produced and net present value had been analyzed to evaluate its techno-economic viability.FindingsComputational fluid dynamics (CFD) analysis of National Advisory Committee for Aeronautics (NACA) 0020 blade has been carried out. For a turbine with wind speed of 50 m/s and swept area of 8 m2, the power generated is 245 kW. For eight trains that operate for 19 h/day with an interval of 30 min in nonpeak hours and 15 min in peak hours, total energy generated is 66 MWh/day. The average cost saved by the train stations is RM 16.7 mil/year with battery charging capacity of 12 h/day.Originality/valueWind energy harvesting is not commonly used in Malaysia due to its low wind speed ranging from 1.5 to 4.5 m/s. Conventional wind turbine requires a minimum cut-in wind speed of 11 m/s to overcome the inertia and starts generating power. Hence, this paper proposes an optimum design of VAWT to harvest an unconventional untapped wind sources from railway. The research finding complements the alternate energy harvesting technologies which can serve as reference for countries which experienced similar geographic constraints.

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“…The membrane was sandwiched by rubber, which flutters elastically when an airflow of 13 to 25 ms −1 passes through the EH. 104 In wind tunnel tests, the prototype produced a power of 50 mW at a wind velocity of 18.67 km/h. 102 Figure 26 illustrates the simulated outputs of using single and multiple layers of aeroelastics VEH.…”

Section: Aeroelastics or Flusteringmentioning

confidence: 99%

“…34 Otherwise, a fluttering belt attached to an EM VEH was also tested. 104 In wind tunnel tests, the prototype produced a power of 50 mW at a wind velocity of 18.67 km/h. 34 The PE flutter EH system is recommended over wind turbine generation for quieter, safer, and more space-efficient operation.…”

Section: Aeroelastics or Flusteringmentioning

confidence: 99%

Review of vibration-based energy harvesting technology: Mechanism and architectural approach

2018

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Summary Energy harvesting technologies are growing rapidly in recent years because of limitation by energy storage and wired power supply. Vibration energy is abundant in the atmosphere and has the potential to be harvested by different mechanisms, mainly through piezoelectric and electromagnetic means. Various architectural structures were also designed for several operating conditions, namely, resonance frequency and range thereof, acceleration, and energy extraction from several motions. The advantages and disadvantages were elaborated on, and improvements on ideas from current research were discussed in this review.

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Karman Vortex Creation Using Cylinder for Flutter Energy Harvester Device

Cited by 11 publications

References 28 publications

Experimental Study of Overland Flow through Rigid Emergent Vegetation with Different Densities and Location Arrangements

Experimental Study of Overland Flow through Rigid Emergent Vegetation with Different Densities and Location Arrangements

Design and performance evaluation of vertical axis wind turbine for wind energy harvesting at railway

Review of vibration-based energy harvesting technology: Mechanism and architectural approach

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