Numerical Investigation Into the Effects of Motion Parameters on Energy Extraction of the Parallel Foils

2018 ◽  
Vol 141 (6) ◽  
Author(s):  
Y. L. Wang ◽  
W. Jiang ◽  
Y. H. Xie
Keyword(s):  
Laminar Flow ◽  
Two Dimensional ◽  
Energy Extraction ◽  
Flow Simulations ◽  
Reduced Frequency ◽  
Wide Range ◽  
Extraction Performance ◽  
Motion Parameters ◽  
Parallel Configuration ◽  
Working Parameters

Due to the deficiency of the research on parallel foils, the parallel configuration of foils is concerned and the effects of motion parameters on energy extraction are systematically discussed in the present study. The foils undergo combined plunging and pitching motions. The effects of motion parameters (pitching amplitude, plunging amplitude, reduced frequency, and spacing between foils) in wide range are investigated at Re = 1100 through two-dimensional (2D) unsteady laminar flow simulations. The features of power output and efficiency changing with these motion parameters as well as the evolution of the vortex fields are gained. The principle that how motion parameters affecting energy extraction performance is studied. The extraction performance of parallel foils and single foil is compared at the optimal working parameters of the single foil. Numerical results indicate the optimal extraction performance of the parallel foils is superior to that of the single foil. CPm improves by 6.87% relatively. Therefore, it reveals that the parallel foils can perform the better extraction characteristics than the single foil by controlling parameters.

Experimental and Numerical Study on the Flow Field Around a Parallel-Foil Turbine

2020 ◽  
Author(s):  
Yulu Wang ◽  
Di Zhang ◽  
Yonghui Xie
Keyword(s):  
Flow Field ◽  
Aerodynamic Force ◽  
Numerical Study ◽  
Energy Extraction ◽  
Reduced Frequency ◽  
Image Velocimetry ◽  
Efficiency Increase ◽  
Oscillation Process ◽  
Effective Angle ◽  
Extraction Performance

Abstract An experiment facility of parallel-foil turbine is proposed in this study. The flow field around foils at different reduced frequency, pitching amplitude and plunging amplitude is measured by 2D Particle Image Velocimetry (PIV) system. And the energy extraction performance at different motion parameters is analyzed numerically. The comparison between experimental and numerical flow field is conducted at different reduced frequency. The evolution of flow field and the aerodynamic force with different pitching amplitude and plunging amplitude are discussed. The effect of pitching amplitude and plunging amplitude on energy extraction performance is obtained. Results indicate that the pitching amplitude can increase the range and the strength of acceleration area by varying the pitching velocity and the effective angle of attack. The optimal extraction performance appears at 70°. Due to the increase in plunging amplitude, the energy extraction performance and efficiency increase gradually. The optimal plunging amplitude is 1.0. The pitching amplitude and the plunging amplitude influence the power output by affecting the vortex shedding and the flow reattachment in oscillation process.

scholarly journals Two dimensional simulation of laminar flow by three- jet in a semi-confined space

2020 ◽  
Vol 9 (1) ◽  
pp. 111-117
Author(s):  
Mohammad Mosaddeghi
Keyword(s):  
Laminar Flow ◽  
Transient Flow ◽  
Flow Characteristics ◽  
Reynolds Numbers ◽  
Two Dimensional ◽  
Confined Space ◽  
Wide Range ◽  
Critical Reynolds Numbers ◽  
Dimensional Simulation ◽  
Geometric Changes

AbstractEquipment performance improvement in a wide range of working conditions is one of the major goals of aerodynamics. This goal can be achieved by the deformation of the object being examined or by using flow control techniques in active or inactive modes. In different researches, how to change the development ratio on the semi-confined space with input jet system is surveyed. In this study, two-dimensional simulation of the flow has been investigated in three-jet laminar flow in a semi-confined space. To determine the effective and optimal mixing in a laminar flow, critical Reynolds numbers were determined to distinguish when the flow in the channel from a steady-state symmetric flowformed downstream recirculation and ultimately transient flow. To better understand the flow characteristics, the simulations were changed at a fixed jet spacing (input jets distance to height of space ratio). Also, in this paper, for comparison, four jets were considered. Based on the results, it was observed that in all cases, mixing occurred in the space between three jets. Placing the jet along the walls of the semi-confined space allows the best combination, and increase in the distance between the first and third jets and reduction of the particle coefficient caused to reach the critical Reynolds number faster and, as a result, mixing in a laminar flow with geometric changes of the semi-confined space.

Study on Performance Enhancement of a Flapping Foil Energy Harvester Using Circulation Control

2021 ◽  
Vol 143 (7) ◽  
Author(s):  
Fangrui Shi ◽  
Xiaojing Sun
Keyword(s):  
Extraction Efficiency ◽  
Performance Enhancement ◽  
Net Energy ◽  
Circulation Control ◽  
Energy Extraction ◽  
Injection Port ◽  
Flapping Foil ◽  
Momentum Coefficient ◽  
Reduced Frequency ◽  
Wide Range

Abstract Oscillating motion, an effective way to harvest energy, has gradually become a hotspot in bionic motion research in recent years. Means of improving the energy-extraction efficiency of a flapping foil harvester have long been a focus of researchers. This paper proposes a new flapping foil harvester with circulation control and explores the effects of different parameters on its energy-extraction capacity to improve efficiency and achieve lowest cost. Setting the injection ports on the upper and lower surfaces near the trailing edge of the foil and implementing injection control during motion, the effects of the location of the injection port, pitching amplitude, momentum coefficient, reduced frequency, and jet mode on the circulation control flapping foil are systematically investigated under the condition of a Reynolds number of 13,800. The results show that circulation control can enhance the energy-extraction efficiency of a flapping foil across a wide range of parameters, in which the location of the injection port and momentum coefficient have the most obvious influence on efficiency, followed by pitching amplitude and reduced frequency. In addition, the jet mode is a crucial factor affecting net efficiency. Relative to the constant mode, the triangular mode of circulation control has the lowest energy consumption, and the net energy-extraction efficiency reaches up to 38.77% under a reduced frequency of 0.12, which is 22.24% higher than that of the plain flapping foil.

Numerical Investigation Into the Energy Extraction Characteristics of Parallel Dual-Foil Turbine

2018 ◽  
Author(s):  
Wei Jiang ◽  
Yulu Wang ◽  
Yonghui Xie ◽  
Di Zhang
Keyword(s):  
Lift Force ◽  
Ground Effect ◽  
Power Coefficient ◽  
Navier Stokes ◽  
Energy Extraction ◽  
Pitching Motion ◽  
Power Generator ◽  
Higher Power ◽  
Extraction Performance ◽  
Parallel Configuration

A new concept of power generator using two oscillating foils in parallel configuration to extract energy from fluid is proposed and numerically tested in the present study. The theoretical performance of the turbine in this form is investigated through unsteady two-dimensional laminar-flow Navier-Stokes simulations. The effect of the interaction between the two foils is studied at different pitching amplitudes and phase differences between the two foils. The energy extraction performance, instantaneous force coefficients and flow details are compared between single foil and dual foils, and thus the mechanism of performance improvement by wing-in-ground effect is revealed. Two different kinds of asymmetric sinusoidal motions are utilized to further improve the performance of the turbine. Numerical results indicate that anti-phase mode can achieve higher power coefficient than the in-phase mode. The contracted passage under anti-phase mode helps produce larger lift force and power coefficient. The maximum power coefficient per foil for anti-phase dual foils is 1.4% higher than that of single foil. The asymmetric sinusoidal pitching motion in phase can improve the synchronization between plunging velocity and lift force and thus further enhance the energy extraction performance by 1.3%. Besides, the pitching motion with asymmetric amplitude also can increase the power coefficient somehow, but the improvement is very limited.

Aromatic Volatile Composition of Celery and Celeriac Cultivars

HortScience ◽  
1990 ◽  
Vol 25 (5) ◽  
pp. 556-559 ◽  
Author(s):  
Fredy Van Wassenhove ◽  
Patrick Dirinck ◽  
Georges Vulsteke ◽  
Niceas Schamp
Keyword(s):  
Volatile Compounds ◽  
Chromatographic Method ◽  
Apium Graveolens ◽  
Volatile Components ◽  
Two Dimensional ◽  
Qualitative Composition ◽  
Volatile Composition ◽  
Wide Range ◽  
Gas Chromatographic Method ◽  
Identification And Quantification

A two-dimensional capillary gas chromatographic method was developed to separate and quantify aromatic volatiles of celery in one analysis. The isolation, identification, and quantification of the volatile compounds of four cultivars of blanching celery (Apium graveolens L. var. dulce) and six cultivars of celeriac (Apium graveolens L. var. rapaceum) are described. The qualitative composition of Likens-Nickerson extracts of both cultivars is similar. The concentration of terpenes and phthalides, the key volatile components, found in various cultivars of both celery and celeriac varied over a wide range.

Energy extraction performance of a flapping wing with active elastic airbag deformation at the leading edge

2021 ◽  
Vol 228 ◽  
pp. 108901
Author(s):  
Xiao-Dong Bai ◽  
Ji-Sheng Zhang ◽  
Jin-Hai Zheng ◽  
Yong Wang
Keyword(s):  
Leading Edge ◽  
Flapping Wing ◽  
Energy Extraction ◽  
Extraction Performance

scholarly journals Prediction of Wide Range Two-Dimensional Refractivity Using an IDW Interpolation Method from High-Altitude Refractivity Data of Multiple Meteorological Observatories

2021 ◽  
Vol 11 (4) ◽  
pp. 1431
Author(s):  
Sungsik Wang ◽  
Tae Heung Lim ◽  
Kyoungsoo Oh ◽  
Chulhun Seo ◽  
Hosung Choo
Keyword(s):  
High Altitude ◽  
Korean Peninsula ◽  
Interpolation Method ◽  
Atmospheric Condition ◽  
Propagation Path ◽  
Two Dimensional ◽  
Data Set ◽  
Wide Range ◽  
Atmospheric Data ◽  
Terrain Surface

This article proposes a method for the prediction of wide range two-dimensional refractivity for synthetic aperture radar (SAR) applications, using an inverse distance weighted (IDW) interpolation of high-altitude radio refractivity data from multiple meteorological observatories. The radio refractivity is extracted from an atmospheric data set of twenty meteorological observatories around the Korean Peninsula along a given altitude. Then, from the sparse refractive data, the two-dimensional regional radio refractivity of the entire Korean Peninsula is derived using the IDW interpolation, in consideration of the curvature of the Earth. The refractivities of the four seasons in 2019 are derived at the locations of seven meteorological observatories within the Korean Peninsula, using the refractivity data from the other nineteen observatories. The atmospheric refractivities on 15 February 2019 are then evaluated across the entire Korean Peninsula, using the atmospheric data collected from the twenty meteorological observatories. We found that the proposed IDW interpolation has the lowest average, the lowest average root-mean-square error (RMSE) of ∇M (gradient of M), and more continuous results than other methods. To compare the resulting IDW refractivity interpolation for airborne SAR applications, all the propagation path losses across Pohang and Heuksando are obtained using the standard atmospheric condition of ∇M = 118 and the observation-based interpolated atmospheric conditions on 15 February 2019. On the terrain surface ranging from 90 km to 190 km, the average path losses in the standard and derived conditions are 179.7 dB and 182.1 dB, respectively. Finally, based on the air-to-ground scenario in the SAR application, two-dimensional illuminated field intensities on the terrain surface are illustrated.

scholarly journals Energy Extraction Performance of Tandem Ground-effect Hydrofoils

2021 ◽  
Vol 809 (1) ◽  
pp. 012001
Author(s):  
Hao Yang ◽  
Guanghua He ◽  
Weijie Mo ◽  
Wei Wang
Keyword(s):  
Ground Effect ◽  
Energy Extraction ◽  
Extraction Performance
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