Experimental estimation of turbulence modification by inertial particles at moderate<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mi>Re</mml:mi><mml:mi>λ</mml:mi></mml:msub></mml:math>

Mora, Daniel Odens; Cartellier, Alain H.; Obligado, Martín

doi:10.1103/physrevfluids.4.074309

Cited by 14 publications

(17 citation statements)

References 36 publications

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“…Tables 1 Bose et al [38], Monchaux and Dejoan [39] and Malloupas et al [40] showed that two-way coupling makes some difference to the results even for α in the range of 10 -5 to 10 -4 if Reλ < 50, where Reλ is the Reynolds number based on the Taylor microscale length. However, Mora et al [41] found that two-way coupling has some effect on dissipation and settling time for the fluid droplets in their study with Reλ up to 400 or 500. For the flow conditions in the current study, Reλ is in the range 3000 -18000.…”

Section: Cfd Model Description and Simulation Detailsmentioning

confidence: 82%

Performance of a wind turbine blade in sandstorms using a CFD-BEM based neural network

Zidane

Swadener

et al. 2020

Journal of Renewable and Sustainable Energy

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In arid regions, such as the North African desert, sandstorms impose considerable restrictions on horizontal axis wind turbines (HAWT) which have not been thoroughly investigated. This paper examines the effects of debris flow on the power generation of HAWT. Computational Fluid Dynamics (CFD) models were established and validated to provide novel insights on the effects of debris on the aerodynamic characteristics of NACA 63415. To account for the change in chord length and Reynolds number along the span of the blade and the 3D flow patterns, the power curves for a wind turbine were obtained using the Blade Element Momentum (BEM) method. We present a novel coupled application of neural network, CFD and BEM to investigate the erosion rates of the blade due to different sandstorm conditions. The proposed model can be scaled and developed to assist in monitoring and prediction of HAWT blade conditions. This work shows that HAWT performance can be significantly diminished due to the aerodynamic losses under sandstorm conditions. The power generated under debris flow conditions can decrease from 10 to 30 % compared to clean conditions.

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Section: Cfd Model Description and Simulation Detailsmentioning

confidence: 82%

Performance of a wind turbine blade in sandstorms using a CFD-BEM based neural network

Zidane

Swadener

et al. 2020

Journal of Renewable and Sustainable Energy

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“…The tensor invariants of Reynolds stress imply the geometrical and physical information of turbulence fluctuations, which are denoted as Ig,x, Ig,y and Ig,z. using the components of normal and shear Reynolds stress, see Equations ( 7), ( 8) and (9). Now that invariants indicate the fundamental geometrical and physical characteristics of turbulence fluctuations related with stress components, it is more reasonable to observe the modulations on the invariants than those of any individuals.…”

Section: Modulations Of the Tensor Invariants Of The Reynolds Stress mentioning

confidence: 99%

“…Experimental investigations by means of the particle image velocity (PIV), the laser Doppler anemometry (LDA), the phase Doppler particle analyzer (PDPA) and the high speed camera (HSC) have been measured successfully the hydrodynamics of gas-particle turbulent flows [6][7][8][9][10][11][12][13][14][15][16][17] . As for the LDA technique, Kulick et al 1994 [6] studied the interactions between small-dense Copper and glass beads with diameter of 70 μm, 50 μm and 90 μm and gas turbulence behaviors in fully developed channel.…”

Section: Introductionmentioning

confidence: 99%

“…2019 [9] quantified the impact of inertial particle on turbulent kinetic energy, and turbulent kinetic energy dissipation in particle-laden flows. By using of the PIV instrument, Kiger et al 2002 [10] found that the presence of particle noticeably alters the carrier phase turbulence properties through an effective increase in the wall friction velocity of approximately 7%, and an increase of the normal and shear Reynolds stress by approximately 8-10% in the outer flow.…”

Section: Introductionmentioning

confidence: 99%

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Hydrodynamic Modeling of Turbulence Modulation by Particles in Swirling Gas-Particle Two-Phase Flow

Liu

Zhou

2021

Preprint

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Turbulence modulations by particles of swirling gas-particle two-phase flow the axisymmetric chamber is investigated. To fully consider the preferential concentrations and anisotropic dispersions of particle, a second-order moment model coupling particle-particle collision model was improved based on the Eulerian-Eulerian two-fluid approach and the kinetic theory of granular flow. Proposed model, algorithm and in-house codes are validated and they are in good agreement with the experiment. Effects of ultralight expanded graphite and heavy Copper particles with large spans of Stokes number on gas velocity and fluctuations, Reynolds shear stress and tensor invariants, turbulence kinetic energy, and vortices structures are numerically simulated. Results show turbulent modulation exhibits strongly anisotropic characteristics and keeps in close relationship with flow structure. The disturbances of modulations, the alternations of vortex evolution are enforced by heavy-large particle with higher Stokes numbers. Preferential accumulations of light particle at shear stress regions in low vortices are weaker than those of heavy particle. For axial turbulence modulations, heavy particle plays the primary role on inhibition action due to larger inertia and light particle contributes to enhancement effect due to excellent followability.

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“… 9 By use of the PIV instrument, the presence of particles noticeably alters the carrier phase turbulence properties through an effective increase in the wall friction velocity of approximately 7% and an increase in normal and shear Reynolds stress by approximately 8–10% in the outer flow. 10 Particle inertia are of great importance for gas turbulence modification, even if the lower mass loading ratio of 5 × 10 –4 . It was attenuated with increasing particle size and mass loadings.…”

Section: Introductionmentioning

confidence: 99%

Hydrodynamic Modeling of Turbulence Modulation by Particles in a Swirling Gas–Particle Two-Phase Flow

2021

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Turbulence modulations by particles of a swirling gas–particle two-phase flow in an axisymmetric chamber are numerically simulated. To fully consider the preferential concentrations and the anisotropic dispersions of particles, a second-order moment model coupling particle–particle collision model was improved. Experimental validation for the proposed model, algorithm, and in-house codes by acceptable match was carried out. The effects of ultralight-expanded graphite and heavy copper particles with a large span of Stokes number on gas velocities and fluctuations, Reynolds shear stresses and tensor invariants, turbulence kinetic energies, and vortice structures are investigated. The results show that turbulent modulation exhibits strong anisotropic characteristics and remains in a close relationship with the flow structure. Modulation disturbances and vortex evolution are enforced by heavy-large particles with higher Stokes numbers. Preferential accumulations of ultralight particles in shear stress regions at lower vortices are weaker than those of heavy particles. For axial turbulence modulations, a heavy particle plays the primary role in the inhibition action because of larger inertia, and a light particle contributes to the enhancement effect due to excellent followability. The instantaneous flow information and coherent turbulent structure are failed to be acquired due to the limitation of the Reynolds time-averaged algorithm.

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Experimental estimation of turbulence modification by inertial particles at moderateReλ

Cited by 14 publications

References 36 publications

Performance of a wind turbine blade in sandstorms using a CFD-BEM based neural network

Performance of a wind turbine blade in sandstorms using a CFD-BEM based neural network

Hydrodynamic Modeling of Turbulence Modulation by Particles in Swirling Gas-Particle Two-Phase Flow

Hydrodynamic Modeling of Turbulence Modulation by Particles in a Swirling Gas–Particle Two-Phase Flow

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