Abstract
The effects of temperature-dependent viscosity, gravity modulation and thermo-mechanical anisotropies on heat transport in a low-porosity medium are studied using the Ginzburg–Landau model. The effect of gravity modulation is to decrease the Nusselt number, Nu and variable viscosity leads to increase in Nu. The thermo-mechanical anisotropies have opposite effect on Nu with thermal anisotropy decreasing the heat transport.
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Abbreviations
- A :
-
Amplitude of convection
- C :
-
Specific heat capacity
- g = (0, 0, −g):
-
Acceleration due to gravity
- k :
-
Permeability tensor
- k :
-
Wave number
- K h, K v :
-
Permeability in horizontal and vertical direction
- Nu :
-
Nusselt number
- p :
-
Dynamic pressure
- q = (u, 0, w):
-
Velocity vector
- Ra :
-
Darcy-Rayleigh number
- T :
-
Temperature
- t :
-
Time
- V :
-
Variable viscosity parameter
- Va :
-
Darcy–Prandtl number or Vadasz number
- (x, z):
-
Horizontal and vertical coordinates
- α :
-
Coefficient of thermal expansion
- γ :
-
Ratio of heat capacity
- δ 0 :
-
Small parameter indicating variation of viscosity with temperature
- δ 1 :
-
Amplitude of gravity modulation
- \({\epsilon = \frac{K_{\rm h}}{K_{\rm v}}}\) :
-
Ratio of permeabilities in horizontal and vertical direction (mechanical anisotropy parameter)
- \({\epsilon_{1}}\) :
-
Small quantity indicative of weak variation
- \({\eta = \frac{\chi_{\rm h}}{\chi_{\rm v}}}\) :
-
Ratio of conductivities in horizontal and vertical direction (thermal anisotropy parameter)
- μ :
-
Fluid viscosity
- ν :
-
Kinematic viscosity
- ρ, ρ 0 :
-
Fluid density and reference fluid density
- χ h, χ v :
-
Thermometric conductivity in horizontal and vertical direction
- ψ :
-
Stream function
- Ω 0 :
-
Dimensional frequency of gravity modulation
- b:
-
Basic state
- f:
-
Property pertaining to fluid
- m:
-
Property pertaining to porous media
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Siddheshwar, P.G., Vanishree, R.K. & Melson, A.C. Study of Heat Transport in Bénard-Darcy Convection with g-Jitter and Thermo-Mechanical Anisotropy in Variable Viscosity Liquids. Transp Porous Med 92, 277–288 (2012). https://doi.org/10.1007/s11242-011-9901-z
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DOI: https://doi.org/10.1007/s11242-011-9901-z