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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High-fidelity numerical simulation of unsteady cavitating flow around a hydrofoil

Journal of Hydrodynamics, Journal Year: 2023, Volume and Issue: 35(1), P. 1 - 16

Published: Feb. 1, 2023

Language: Английский

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Surface cavitation flow characterization of jet hydrofoils based on vortex identification method

Physics of Fluids, Journal Year: 2022, Volume and Issue: 35(1)

Published: Dec. 16, 2022

The vortex structure is a typically coherent structure. influence of hydrofoil jets with different chordal positions on the in flow field investigated to improve suppression mechanism cavitation by jet hydrofoils. investigation based identification method and position best effect large-scale surface explored. In addition, dynamics states are analyzed means transport equations optimal chordwise position. results show that U-shaped main morphology bubble shedding; form shedding surface; compared original other positions, can be suppressed better when located at 0.6c; dominant vorticity terms various stages. primary stage, dilatation term dominant. contrast, during development, maturation, phases, stretching dominates, reducing pressure gradient suppressing strength return jet.

Language: Английский

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Wake interference of tandem wind turbines considering pitch strategy based on the AL-LDS-Ωnew coupling method

Frontiers in Energy Research, Journal Year: 2024, Volume and Issue: 12

Published: Aug. 12, 2024

This paper establishes a high-fidelity and efficient Computational Fluid Dynamics (CFD) numerical method (AL-LDS-Ω new ) for wind turbine wake by combining the actuator line (AL), localized dynamic Smagorinsky (LDS) sub-grid scale (SGS), generation Ω vortex identification under framework of large eddy simulation. The model advantages are encouraging: 1) In terms modeling, AL is adopted to replace traditional three-dimensional solid model, which avoids solving boundary layer on blade surface improves computational efficiency; 2) simulation, LDS SGS used turbulence, reducing dissipation further improving refinement wake; 3) identification, difficult threshold selection in previous captures more refined structures. accuracy validated against published data NREL 5 MW turbine, then extended simulate interference tandem twin-rotor turbines changing pitch angle upstream (WT1). influence mechanisms between array energy conversion efficiency strategy explored, demonstrating AL-LDS-Ω coupling computationally accurate simulating complex interference. From analyses, can effectively suppress effect (WT1) increase power output downstream (WT2), thus overall farm. Compared with non-pitch condition (0 angle), (2°) maximizes global array: augmentation 0.29%, thrust reduction 5%. optimal state reduces fatigue load conducive long-term operation. findings, whilst preliminary, encourage use strategies farm planning

Language: Английский

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Investigation of correlation between vorticity, Q, λci, λ2, Δ

Computers & Fluids, Journal Year: 2021, Volume and Issue: 225, P. 104977 - 104977

Published: May 6, 2021

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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Identification and analysis of the inlet vortex of an axial-flow pump

Journal of Hydrodynamics, Journal Year: 2022, Volume and Issue: 34(2), P. 234 - 243

Published: April 1, 2022

Language: Английский

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Modeling study of the energy separation effect of a control valve structure on a vortex tube

Case Studies in Thermal Engineering, Journal Year: 2024, Volume and Issue: 61, P. 104828 - 104828

Published: July 17, 2024

This paper compares the effect of different angles triangular conical and truncated regulating valves on heat cold separation vortex tubes. Numerical simulation experimental studies show that60° cone valve has better cooling effect. The inlet pressure is in range 0.2MPa–0.4 MPa, temperature rate change at end tube larger numerical smaller. Under same circumstances, connected to area cold-heat exchange hot end, as well location fluid's stagnation point. merging related angle form valve. data results are relative agreement with each other, maximum difference being 4.41 % minimum 3.52 %. validated by house validation method using theoretical model study, control trend model.

Language: Английский

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Numerical investigation into air flow separation around ship based on the wall-modeled large eddy simulation

Physics of Fluids, Journal Year: 2025, Volume and Issue: 37(5)

Published: May 1, 2025

The problem of strong flow separation presents challenges in terms both the accuracy and computational cost numerical simulation methods. To address issue where traditional wall-resolved large eddy (WRLES) methods offer high but require fine-scale grids, Reynolds-averaged Navier–Stokes are computationally efficient struggle to capture transient turbulent structures, this study introduces a wall-modeled (WMLES) method with multi-layer grid mapping. In method, WRLES is employed bulk solve velocity pressure fields, while wall model used compute shear stress near wall. Based on appropriate partitioning strategies, simulations Reynolds number airflow field around Simple Frigate Ship conducted. comparison between WMLES, results, experimental data indicates that WMLES effectively reduces potential for random errors introduced by single-layer mapping can successfully boundary layer redevelopment phenomena. Moreover, it offers significantly lower compared methods, providing practical problems.

Language: Английский

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On the Vortical Characteristics of Horn-Like Vortices in Stator Corner Separation Flow in an Axial Flow Pump

Journal of Fluids Engineering, Journal Year: 2021, Volume and Issue: 143(6)

Published: Jan. 14, 2021

Abstract The phenomenon of horn-like vortex in stator corner separation flow an axial pump was first reported by Wang et al. (2020, “Investigation on the Horn-Like Vortices Stator Corner Separation Flow Axial Pump,” ASME J. Fluids Eng., 142(7), p. 071208), and associated external features were preliminarily presented. However, internal vortical characteristics vortices, including distributions swirling strength, deformation mechanism tube correlation with pressure fluctuation surge, are not revealed. In this paper, newly developed vorticity decomposition approach is introduced, thus more novel quantitative results provided for physics evolution pump. First, absolute relative strength Liutex spectrum presented to outline fields. Second, It found that spatial can be described terms (Liutex stretching term, dilatation curl term pseudo-Lamb vector) controlling transport process. These constantly act almost independent way, causing its continuous deformations transit Third, between surge given. proved periodic cause severe much larger than induced rotor–stator interaction. From multiple perspectives, a clearer process outlined, which conducive flows improving stability large-capacity low-head pumping stations.

Language: Английский

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