Flow dynamics and sediment transport in vegetated rivers: A review

Journal of Hydrodynamics, Journal Year: 2021, Volume and Issue: 33(3), P. 400 - 420

Published: June 1, 2021

Language: Английский

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On the effects of hybrid surface wettability on the structure of cavitating flow using implicit large eddy simulation

Journal of the Taiwan Institute of Chemical Engineers, Journal Year: 2023, Volume and Issue: 148, P. 104828 - 104828

Published: March 22, 2023

Language: Английский

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Investigations on the performance and wake dynamics of a tidal stream turbine under different yaw-offset conditions

Physics of Fluids, Journal Year: 2025, Volume and Issue: 37(1)

Published: Jan. 1, 2025

The misalignment between flow and rotor can significantly alter the efficiency of tidal stream turbine (TST), therefore, it is vital to predict in field performance TST under yaw-offset conditions. First, this paper implements a high-precision Lagrangian dynamic sub-grid-scale model based on large-eddy simulation (LES) method. A classical computational fluid dynamics benchmark case selected validate accuracy LES (DLES) results indicate that newly implemented method exhibits reduced dissipation effectively captures local effects non-uniform fields, including vortex structures. Second, an efficient high-fidelity numerical (AL-DLES) for forecasting wake presented by integrating actuator line (AL) code with aforementioned DLES framework. After comparing experimental results, was discovered developed AL-DLES coupling approach, which addresses issues challenging meshing, rapid dissipation, insufficient fidelity previous methods, accurately simulate forces acting while also capturing detailed characteristics field. Furthermore, study will be extended investigate various conditions, exploring mechanisms instability evolution meandering. Meanwhile, latest third-generation (Ωnew) identification program successfully applied visualization Through comparative analysis three distinct approaches, demonstrated Ωnew superior system located behind rotor, eliminating need manual threshold selection. In addition, capable simultaneously both strong weak vortices, aspect future research.

Language: Английский

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An experimental investigation of transient cavitation control on a hydrofoil using hemispherical vortex generators

Journal of Hydrodynamics, Journal Year: 2021, Volume and Issue: 33(6), P. 1139 - 1147

Published: Dec. 1, 2021

Language: Английский

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Hydraulic loss analysis in a pump-turbine with special emphasis on local rigid vortex and shear

Physics of Fluids, Journal Year: 2022, Volume and Issue: 34(12)

Published: Nov. 10, 2022

Since the pump as turbine is increasingly employed in energy storage, improving efficiency both and modes required for economic benefits. This study aims to analyze vortex flow characteristics control methods reduce hydraulic loss. In this paper, a delayed detached eddy simulation was applied low specific speed pump-turbine. Based on entropy production analysis vorticity binary decomposition local vortices, results show that shear leading cause of loss instead existence vortices. The average wake can be 1.6 times higher than jet regions mode, but there little difference distribution vortices mode. caused by rotor–stator interaction with tongue effect at blade passing frequency up threefold over without modes. Reducing ratio rigid via modification volute angle suppress an effective way decrease

Language: Английский

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Numerical study of the kinematic and acoustic characteristics of bubble clusters

Journal of Hydrodynamics, Journal Year: 2023, Volume and Issue: 35(1), P. 61 - 75

Published: Feb. 1, 2023

Language: Английский

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Noise analysis in the centrifugal pump based on vortex sound theory with vorticity binary decomposition

Physics of Fluids, Journal Year: 2023, Volume and Issue: 35(2)

Published: Feb. 1, 2023

This paper aims to analyze the sound and pseudo-sound generation mechanism its corresponding control method in a centrifugal pump. The delayed detached eddy simulation vortex theory are applied calculate flow acoustic fields. prediction results agree well with experimental results. Based on vorticity binary decomposition, influence of components rigid shear fluctuation is discussed. show that source dominated by shearing part rather than vorticity. Sound pressure levels could be amplified when gets intense, but less sensitive. amplitude threefold over spiral casing, while becomes higher at outlet as former decay slowly along tube. Increasing volute tongue angle reduce tube, leading decrease much 44% 10% pseudo-sound.

Language: Английский

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Comparative Study of Different Turbulence Models for Cavitational Flows around NACA0012 Hydrofoil

Journal of Marine Science and Engineering, Journal Year: 2021, Volume and Issue: 9(7), P. 742 - 742

Published: July 5, 2021

The present work focuses on the comparison of numerical simulation sheet/cloud cavitation with Reynolds Average Navier-Stokes and Large Eddy Simulation(RANS LES) methods around NACA0012 hydrofoil in water flow. Three kinds turbulence models—SST k-ω, modified SST Smagorinsky’s model—were used this paper. unstable sheet cavity periodic shedding were predicted, results, namelycavitation shape, frequency, lift drag coefficients those three models, analyzed compared each other. results above basically accordance experimental ones. It was found that k-ω Smagorinsky models performed better aspects capturing unsteady vortex cluster developing period at number σ = 0.8. At a small angle attack, model more accurate practical than other two models. However, large LES method able to give specific information flow field, which RANS could not give. Further study showed structure wing is main cause shedding.

Language: Английский

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Research on complex wake interference of aligned rotors considering the precone variation of the upstream wind turbine

Frontiers in Marine Science, Journal Year: 2022, Volume and Issue: 9

Published: Dec. 6, 2022

To understand the interaction wake effects of aligned horizontal-axis wind turbines, a refined and low-cost simulation framework is developed by combining actuator line (AL) with local dynamic Smagorinsky (LDS) model. Firstly, published performance NREL-5MW turbine used to corroborate accuracy AL-LDS coupling Secondly, research extended predict interference between two tandem rotor wakes. The influence precone characteristics on overall power output turbines explored modifying upstream introducing latest third-generation Ω vortex identification method in post-processing procedure. According results, have complex interference, angle variation always reducing global power, leading an unstable downstream wake. This detrimental system lifespan due high fluctuation stress as well may ecological implications sediment alteration. From upwind (negative) can lead higher but lower performance, compared non-tilted turbine. Despite optimal 0°, -2.5° proves more advantageous owing large flexible deformation wingtips. findings serve continuous incentive for improving farm numerical simulation.

Language: Английский

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Liutex-based centripetal force field model for improving the resistance and wake performances of JBC ship sailing in calm water

Journal of Hydrodynamics, Journal Year: 2021, Volume and Issue: 33(3), P. 494 - 502

Published: June 1, 2021

Language: Английский

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