Fluid structures of flapping airfoil with elliptical motion trajectory

Esfahani, Javad Abolfazli; Barati, E.; Karbasian, Hamid Reza

doi:10.1016/j.compfluid.2014.12.002

Cited by 50 publications

(10 citation statements)

References 32 publications

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“…In order to ensure the accuracy of the calculation results and avoid the time step affecting the calculation accuracy, according to YU, Esfahani [10,11], and others' discussions, the calculation accuracy can be guaranteed when the time step ∆t = T/3000. In this study, in order to ensure the accuracy of numerical calculation, three groups of ∆t = T/3000, ∆t = T/3600, and ∆t = T/4000 were selected for trial calculation.…”

Section: Numerical Verificationmentioning

confidence: 99%

“…In the past, research on motion trajectories have mostly focused on the combined pitch and heave motion. Esfahani's [11] research found that adding a reciprocating horizontal motion to the pitch and heave motion makes its trajectory into an ellipse, changes its effective angle of attack profile, and subsequently changes the vortex shedding pattern and wake area of the trailing edge of the wing, which significantly improves the propulsion performance of the flapping hydrofoil. Subsequently, Chen et al [12] studied the propulsion performance of different elliptical motion trajectories of the flapping hydrofoil and gave a set of motion parameters with excellent propulsion performance by changing the ratio of the maximum amplitude of the heave motion to the horizontal motion and its phase difference.…”

Section: Introductionmentioning

confidence: 99%

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Optimal Matching of Flapping Hydrofoil Propulsion Performance Considering Interaction Effects of Motion Parameters

Wang

Chang

Hou

et al. 2022

JMSE

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In order to maximize the propulsion efficiency of flapping hydrofoil, a new method is proposed in this paper. The effects of heave amplitude, pitch amplitude, and the phase difference between heave and surge on propulsion performance were analyzed by numerical calculation, and it was found that three motion parameters had interactive effects on flapping hydrofoil propulsion performance. BP neural network was used to fit the three motion parameters and propulsion performance. Using this function model, the optimal motion parameters can be obtained under certain thrust. In this study, the optimization matching under certain thrust was carried out by using this method, and the propulsion efficiency was improved by 7.73%.

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Section: Numerical Verificationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Optimal Matching of Flapping Hydrofoil Propulsion Performance Considering Interaction Effects of Motion Parameters

Wang

Chang

Hou

et al. 2022

JMSE

View full text Add to dashboard Cite

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“…The amalgamation of these motions constructs an elliptical trajectory (path) of the pitching ellipse. This kind of kinematics is seen in the flying birds, aquatic animals, and has potential applications in high-efficiency Micro Air Vehicles (MAVs), and other energy harvesting vertical axis wind turbine (VAWT) designs [78,79,80,81].…”

Section: Plunging Ellipse With Elliptical Motion Trajectorymentioning

confidence: 99%

Parallel adaptive weakly-compressible SPH for complex moving geometries

Haftu,

Muta,

Ramachandran

2022

Preprint

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The use of adaptive spatial resolution to simulate flows of practical interest using Smoothed Particle Hydrodynamics (SPH) is of considerable importance. Recently, Muta and Ramachandran [1] have proposed an efficient adaptive SPH method where the particle resolution may change by a factor of 1000 in the fluid. This allows the authors to simulate problems with much fewer particles than was possible earlier. The method was not demonstrated or tested with moving bodies or multiple bodies. In addition, the original method employed a large number of background particles to determine the spatial resolution of the fluid particles. In the present work we establish the formulation's effectiveness for simulating flow around stationary and moving geometries. We eliminate the need for the background particles in order to specify the geometry-based or solution-based adaptivity and we discuss the algorithms employed in detail. We consider a variety of benchmark problems, including the flow past two stationary cylinders, flow past different NACA airfoils at a range of Reynolds numbers, a moving square at various Reynolds numbers, and the flow past an oscillating cylinder. We also demonstrate different types of motions using single and multiple bodies. The source code is made available under an open source license, and our results are reproducible.

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“…The retreating blades of the rotor generally work in an aerodynamic environment with a large angle of attack (AoA), and the complex unsteady dynamic stall phenomenon caused by the AoA of most sections of the blade exceeds its stall AoA. The dynamic stall of three-dimensional rotors [4,5] and two-dimensional airfoils [6][7][8] is investigated which indicates that the dynamic stall has a great influence on their aerodynamic performance.…”

Section: Introductionmentioning

confidence: 99%

Study on Dynamic Stall Control of Rotor Airfoil Based on Coflow Jet

Liu

Chen

Qiu

et al. 2020

International Journal of Aerospace Engineering

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In this study, a dynamic stall control strategy, called the co-flow jet (CFJ), is applied to the rotor airfoil. The effect of the CFJ on the unsteady dynamic stall characteristics of the rotor airfoil is numerically investigated via numerical simulations of the unsteady Reynolds-averaged Navier-Stokes (URANS) equations coupled with the Spalart-Allmaras (S-A) turbulence model. The numerical methods are validated by a NACA0012 pitching airfoil case and a NACA6415 airfoil case based on the CFJ, and good agreement with experiments is found. Via the study of the typical conditions of CFJ control to suppress the dynamic stall of the OA212 rotor airfoil, it is verified that this method has a good effect on dynamic stall suppression. The diffusion and blending of the turbulent shear layer between the CFJ injection jet and the main flow excite the main flow and enhance its ability to resist the reverse pressure gradient; this suppresses the generation and development of the separation vortex, thereby enhancing the aerodynamic characteristics, improving the hysteresis effect, and increasing the system stability. On this basis, the control parameters of the CFJ are further studied, including the influences of the jet momentum coefficient and the positions and sizes of the injection and suction slots on suppressing the dynamic stall of the rotor airfoil. It is found that there is a jet momentum coefficient that optimizes the suppression effect of the dynamic stall of the rotor airfoil. Moreover, the position of the injection slot is found to have a greater effect on the dynamic stall suppression, while the size of the injection slot and the position and size of the suction slot have little effect.

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Fluid structures of flapping airfoil with elliptical motion trajectory

Cited by 50 publications

References 32 publications

Optimal Matching of Flapping Hydrofoil Propulsion Performance Considering Interaction Effects of Motion Parameters

Optimal Matching of Flapping Hydrofoil Propulsion Performance Considering Interaction Effects of Motion Parameters

Parallel adaptive weakly-compressible SPH for complex moving geometries

Study on Dynamic Stall Control of Rotor Airfoil Based on Coflow Jet

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