Transient Forced Convection in an Isothermal Fluid-Saturated Porous-Medium Layer: Effective Permeability and Boundary Layer Thickness

2005 ◽  
Vol 8 (2) ◽  
pp. 165-174 ◽  
Author(s):  
Antonio F. Miguel ◽  
A. Heitor Reis
Keyword(s):  
Boundary Layer ◽  
Porous Medium ◽  
Layer Thickness ◽  
Forced Convection ◽  
Boundary Layer Thickness ◽  
Effective Permeability ◽  
Saturated Porous Medium ◽  
Medium Layer ◽  
Isothermal Fluid ◽  
Fluid Saturated Porous Medium

High-Rayleigh-number convection of a reactive solute in a porous medium

2014 ◽  
Vol 760 ◽  
pp. 95-126 ◽  
Author(s):  
T. J. Ward ◽  
O. E. Jensen ◽  
H. Power ◽  
D. S. Riley
Keyword(s):  
Boundary Layer ◽  
Porous Medium ◽  
Rayleigh Number ◽  
Transfer Rate ◽  
Saturated Porous Medium ◽  
Order Unity ◽  
Nonlinear Convection ◽  
Solute Transfer ◽  
Scaling Properties ◽  
Fluid Saturated Porous Medium

AbstractWe consider two-dimensional one-sided convection of a solute in a fluid-saturated porous medium, where the solute decays via a first-order reaction. Fully nonlinear convection is investigated using high-resolution numerical simulations and a low-order model that couples the dynamic boundary layer immediately beneath the distributed solute source to the slender vertical plumes that form beneath. A transient-growth analysis of the boundary layer is used to characterise its excitability. Three asymptotic regimes are investigated in the limit of high Rayleigh number $\mathit{Ra}$, in which the domain is considered deep, shallow or of intermediate depth, and for which the Damköhler number $\mathit{Da}$ is respectively large, small or of order unity. Scaling properties of the flow are identified numerically and rationalised via the analytic model. For fully established high-$\mathit{Ra}$ convection, analysis and simulation suggest that the time-averaged solute transfer rate scales with $\mathit{Ra}$ and the plume horizontal wavenumber with $\mathit{Ra}^{1/2}$, with coefficients modulated by $\mathit{Da}$ in each case. For large $\mathit{Da}$, the rapid reaction rate limits the plume depth and the boundary layer restricts the rate of solute transfer to the bulk, whereas for small $\mathit{Da}$ the average solute transfer rate is ultimately limited by the domain depth and the convection is correspondingly weaker.

Soret and Dufour effects in three-dimensional flow over an exponentially stretching surface with porous medium, chemical reaction and heat source/sink

2015 ◽  
Vol 25 (4) ◽  
pp. 762-781 ◽  
Author(s):  
Tasawar Hayat ◽  
Taseer Muhammad ◽  
Sabir Ali Shehzad ◽  
A. Alsaedi
Keyword(s):  
Boundary Layer ◽  
Porous Medium ◽  
Layer Thickness ◽  
Boundary Layer Thickness ◽  
Three Dimensional ◽  
Stretching Surface ◽  
Three Dimensional Flow ◽  
Soret And Dufour Effects ◽  
Content Type ◽  
Dimensional Flow

Purpose – The purpose of this paper is to study the Soret and Dufour effects in three-dimensional flow induced by an exponential stretching surface in a porous medium. Design/methodology/approach – Series solutions are developed. Findings – The authors observed that the temperature profile and thermal boundary layer thickness are enhanced when the authors increase the values of Dufour number. It is also examined that the concentration field and its associated boundary layer thickness are higher for the larger values of Soret number. Originality/value – Such investigation is not available in the literature.

Sign in / Sign up

Export Citation Format

Share Document