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Title: A direct comparison of particle-resolved and point-particle methods in decaying turbulence

Abstract

We use particle-resolved direct numerical simulation (PR-DNS) as a model-free physics-based numerical approach to validate particle acceleration modelling in gas-solid suspensions. To isolate the effect of the particle acceleration model, we focus on point-particle direct numerical simulation (PP-DNS) of a collision-free dilute suspension with solid-phase volume fraction$$\unicode[STIX]{x1D719}=0.001$$in a decaying isotropic turbulent particle-laden flow. The particle diameter$$d_{p}$$in the suspension is chosen to be the same as the initial Kolmogorov length scale$$\unicode[STIX]{x1D702}_{0}$$($$d_{p}/\unicode[STIX]{x1D702}_{0}=1$$) in order to overlap with the regime where PP-DNS is valid. We assess the point-particle acceleration model for two different particle Stokes numbers,$$St_{\unicode[STIX]{x1D702}}=1$$and 100. For the high Stokes number case, the Stokes drag model for particle acceleration under-predicts the true particle acceleration. In addition, second moment quantities which play key roles in the physical evolution of the gas–solid suspension are not correctly captured. Considering finite Reynolds number corrections to the acceleration model improves the prediction of the particle acceleration probability density function and second moment statistics of the point-particle model compared with the particle-resolved simulation. We also find that accounting for the undisturbed fluid velocity in the acceleration model can be of greater importance than using the most appropriate acceleration model for a given physical problem.

Authors:
; ; ORCiD logo; ORCiD logo
Publication Date:
Research Org.:
Univ. of Colorado, Boulder, CO (United States); Stanford Univ., CA (United States)
Sponsoring Org.:
USDOE Office of Fossil Energy (FE)
OSTI Identifier:
1538914
DOE Contract Number:  
FC26-07NT43098; NA0002373
Resource Type:
Journal Article
Journal Name:
Journal of Fluid Mechanics
Additional Journal Information:
Journal Volume: 850; Journal ID: ISSN 0022-1120
Publisher:
Cambridge University Press
Country of Publication:
United States
Language:
English
Subject:
Mechanics; Physics

Citation Formats

Mehrabadi, M., Horwitz, J. A. K., Subramaniam, S., and Mani, A. A direct comparison of particle-resolved and point-particle methods in decaying turbulence. United States: N. p., 2018. Web. doi:10.1017/jfm.2018.442.
Mehrabadi, M., Horwitz, J. A. K., Subramaniam, S., & Mani, A. A direct comparison of particle-resolved and point-particle methods in decaying turbulence. United States. doi:10.1017/jfm.2018.442.
Mehrabadi, M., Horwitz, J. A. K., Subramaniam, S., and Mani, A. Wed . "A direct comparison of particle-resolved and point-particle methods in decaying turbulence". United States. doi:10.1017/jfm.2018.442.
@article{osti_1538914,
title = {A direct comparison of particle-resolved and point-particle methods in decaying turbulence},
author = {Mehrabadi, M. and Horwitz, J. A. K. and Subramaniam, S. and Mani, A.},
abstractNote = {We use particle-resolved direct numerical simulation (PR-DNS) as a model-free physics-based numerical approach to validate particle acceleration modelling in gas-solid suspensions. To isolate the effect of the particle acceleration model, we focus on point-particle direct numerical simulation (PP-DNS) of a collision-free dilute suspension with solid-phase volume fraction$\unicode[STIX]{x1D719}=0.001$in a decaying isotropic turbulent particle-laden flow. The particle diameter$d_{p}$in the suspension is chosen to be the same as the initial Kolmogorov length scale$\unicode[STIX]{x1D702}_{0}$($d_{p}/\unicode[STIX]{x1D702}_{0}=1$) in order to overlap with the regime where PP-DNS is valid. We assess the point-particle acceleration model for two different particle Stokes numbers,$St_{\unicode[STIX]{x1D702}}=1$and 100. For the high Stokes number case, the Stokes drag model for particle acceleration under-predicts the true particle acceleration. In addition, second moment quantities which play key roles in the physical evolution of the gas–solid suspension are not correctly captured. Considering finite Reynolds number corrections to the acceleration model improves the prediction of the particle acceleration probability density function and second moment statistics of the point-particle model compared with the particle-resolved simulation. We also find that accounting for the undisturbed fluid velocity in the acceleration model can be of greater importance than using the most appropriate acceleration model for a given physical problem.},
doi = {10.1017/jfm.2018.442},
journal = {Journal of Fluid Mechanics},
issn = {0022-1120},
number = ,
volume = 850,
place = {United States},
year = {2018},
month = {7}
}