Hydrodynamic dispersion in steady buoyancy-driven geological flows

Hamid Emami-Meybodi, H. Hassanzadeh

Research output: Contribution to journalArticle

11 Citations (Scopus)

Abstract

An analytical model is developed to evaluate mixing induced by natural convection in a fluid-saturated porous medium. First, the velocity and concentration fields are decoupled to generate a steady state velocity field and initiate a naturally convective system. In order to decouple the velocity and concentration fields, a steady thermal natural convection is established by imposing a destabilizing vertical temperature gradient across a porous layer and then introducing a passive tracer into the system. Based on the steady velocity field, effective longitudinal and transverse dispersion coefficients are evaluated using the shear flow dispersion theory, and convective mixing of the passive tracer is obtained using the developed analytical mixing model. The estimated dispersion coefficients and convective mixing are then characterized by the system Rayleigh and Sherwood numbers. The mixing obtained by the analytical model is then compared with high-resolution numerical simulations. The results reveal that the simple analytical solution represents the nonlinear mixing involved in such a system and agrees with the numerical results. The developed model has potential applications in geophysical and geothermal buoyancy-driven flows.

Original languageEnglish (US)
Article numberW12504
JournalWater Resources Research
Volume47
Issue number12
DOIs
StatePublished - Dec 19 2011

Fingerprint

buoyancy
hydrodynamics
convection
tracer
shear flow
convective system
temperature gradient
porous medium
fluid
simulation

All Science Journal Classification (ASJC) codes

  • Water Science and Technology

Cite this

@article{8192bec4f83a4c7397f926e3df566349,
title = "Hydrodynamic dispersion in steady buoyancy-driven geological flows",
abstract = "An analytical model is developed to evaluate mixing induced by natural convection in a fluid-saturated porous medium. First, the velocity and concentration fields are decoupled to generate a steady state velocity field and initiate a naturally convective system. In order to decouple the velocity and concentration fields, a steady thermal natural convection is established by imposing a destabilizing vertical temperature gradient across a porous layer and then introducing a passive tracer into the system. Based on the steady velocity field, effective longitudinal and transverse dispersion coefficients are evaluated using the shear flow dispersion theory, and convective mixing of the passive tracer is obtained using the developed analytical mixing model. The estimated dispersion coefficients and convective mixing are then characterized by the system Rayleigh and Sherwood numbers. The mixing obtained by the analytical model is then compared with high-resolution numerical simulations. The results reveal that the simple analytical solution represents the nonlinear mixing involved in such a system and agrees with the numerical results. The developed model has potential applications in geophysical and geothermal buoyancy-driven flows.",
author = "Hamid Emami-Meybodi and H. Hassanzadeh",
year = "2011",
month = "12",
day = "19",
doi = "10.1029/2011WR010949",
language = "English (US)",
volume = "47",
journal = "Water Resources Research",
issn = "0043-1397",
publisher = "American Geophysical Union",
number = "12",

}

Hydrodynamic dispersion in steady buoyancy-driven geological flows. / Emami-Meybodi, Hamid; Hassanzadeh, H.

In: Water Resources Research, Vol. 47, No. 12, W12504, 19.12.2011.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Hydrodynamic dispersion in steady buoyancy-driven geological flows

AU - Emami-Meybodi, Hamid

AU - Hassanzadeh, H.

PY - 2011/12/19

Y1 - 2011/12/19

N2 - An analytical model is developed to evaluate mixing induced by natural convection in a fluid-saturated porous medium. First, the velocity and concentration fields are decoupled to generate a steady state velocity field and initiate a naturally convective system. In order to decouple the velocity and concentration fields, a steady thermal natural convection is established by imposing a destabilizing vertical temperature gradient across a porous layer and then introducing a passive tracer into the system. Based on the steady velocity field, effective longitudinal and transverse dispersion coefficients are evaluated using the shear flow dispersion theory, and convective mixing of the passive tracer is obtained using the developed analytical mixing model. The estimated dispersion coefficients and convective mixing are then characterized by the system Rayleigh and Sherwood numbers. The mixing obtained by the analytical model is then compared with high-resolution numerical simulations. The results reveal that the simple analytical solution represents the nonlinear mixing involved in such a system and agrees with the numerical results. The developed model has potential applications in geophysical and geothermal buoyancy-driven flows.

AB - An analytical model is developed to evaluate mixing induced by natural convection in a fluid-saturated porous medium. First, the velocity and concentration fields are decoupled to generate a steady state velocity field and initiate a naturally convective system. In order to decouple the velocity and concentration fields, a steady thermal natural convection is established by imposing a destabilizing vertical temperature gradient across a porous layer and then introducing a passive tracer into the system. Based on the steady velocity field, effective longitudinal and transverse dispersion coefficients are evaluated using the shear flow dispersion theory, and convective mixing of the passive tracer is obtained using the developed analytical mixing model. The estimated dispersion coefficients and convective mixing are then characterized by the system Rayleigh and Sherwood numbers. The mixing obtained by the analytical model is then compared with high-resolution numerical simulations. The results reveal that the simple analytical solution represents the nonlinear mixing involved in such a system and agrees with the numerical results. The developed model has potential applications in geophysical and geothermal buoyancy-driven flows.

UR - http://www.scopus.com/inward/record.url?scp=83455205908&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=83455205908&partnerID=8YFLogxK

U2 - 10.1029/2011WR010949

DO - 10.1029/2011WR010949

M3 - Article

AN - SCOPUS:83455205908

VL - 47

JO - Water Resources Research

JF - Water Resources Research

SN - 0043-1397

IS - 12

M1 - W12504

ER -