Stratified Fluid Saturated Porous Medium Research Articles

Floquet Instability of Gravity-Modulated Salt Fingering in a Porous Medium

Fingering convection in a horizontal doubly stratified fluid-saturated porous medium is examined under the influence of modulating gravitational field. The Brinkman model of momentum transfer is considered, and the Boussinesq approximation is assumed for natural convection. Floquet theory is employed to determine the onset condition within the framework of linear theory. Continued fractions that can handle arbitrary modulational parameters has been used to predict the dynamic instability regions at the marginal state and critical instability boundaries. Certain combinations of solutal Rayleigh and Schmidt numbers give rise to the occurrence of doubly unstable regions. An increase in the modulation amplitude always encourages instability. The competition between synchronous and subharmonic instability modes is observed for a certain range of values of the parameters. Solutal convection is found to introduce closed disconnected instability loops at the marginal state. It is seen that gravity modulation effe...

Numerical Study of Free Convection in a Doubly Stratified Non-Darcy Porous Medium Using Spectral Quasilinearization Method

Abstract Free convection boundary layer flow past a semi-infinite vertical plate in a doubly stratified fluid-saturated porous medium in the presence of constant suction/injection is analyzed. The flow in the porous medium is described by the Brinkman–Forchheimer-based model. A suitable coordinate transformation is introduced, and the obtained system of non-similar, coupled and nonlinear partial differential equations is solved numerically using the spectral quasi-linearization method. The effects of buoyancy parameter, Darcy number, Forchheimer parameter, suction/injection parameter, thermal and solutal stratification parameters on the dimensionless velocity, temperature and concentration are presented graphically. Further, the local skin friction coefficient, heat and mass transfer rates are presented graphically.

Non-Darcy Mixed Convection in a Doubly Stratified Porous Medium with Soret-Dufour Effects

This paper presents the nonsimilarity solutions for mixed convection heat and mass transfer along a semi-infinite vertical plate embedded in a doubly stratified fluid saturated porous medium in the presence of Soret and Dufour effects. The flow in the porous medium is described by employing the Darcy-Forchheimer based model. The nonlinear governing equations and their associated boundary conditions are initially cast into dimensionless forms and then solved numerically. The influence of pertinent parameters on dimensionless velocity, temperature, concentration, heat, and mass transfer in terms of the local Nusselt and Sherwood numbers is discussed and presented graphically.

Unsteady Free Convection along an Infinite Vertical Flat Plate Embedded in a Stably Stratified Fluid-Saturated Porous Medium

The problem of unsteady free convection heat transfer from a one-dimensional (parallel) flow along an infinite vertical flat plate embedded in a thermally stratified fluid-saturated porous medium is considered. Flows are induced by a sudden change in the arbitrary temporal plate temperature. By a formal reduction of the corresponding boundary value problems to well-known Fourier heat conduction problems, analytical solutions of the Darcy and energy equations are obtained. Several special cases are discussed in detail.

Non-Darcy free convection induced by a vertical wavy surface in a thermally stratified porous medium

The partial differential equations governing the natural convection heat transfer from a vertical wavy surface in a thermally stratified fluid saturated porous medium are analysed under Forchheimer based non-Darcian assumptions. Based on non-similarity transformation deduced by scale analysis the governing equations are reduced to boundary layer equations. These simplified partial differential equations are solved numerically by a finite difference scheme following the Keller Box approach. Extensive numerical simulations are carried out for various values of wavelength-to-amplitude ratio of wavy vertical surface at different thermal stratification levels of porous medium both under Darcian and non-Darcian assumptions. Results from the current study are compared with those available in literature. In Darcian case local heat fluxes along the wavy vertical surface are periodic with an oscillatory pattern of period, which is exactly half of the period of vertical wavy surface. In the non-Darcian case local heat fluxes continue to be periodic but with a complex oscillatory pattern of period exactly same as that of the vertical wavy surface. Increasing S or Gr ∗ or a leads to a fall in local Nusselt number.

Non-Darcy free convection from vertical surfaces in thermally stratified porous media

In this paper, non-Darcy free convection boundary layer flow along an isothermal vertical plate embedded in a thermally stratified fluid saturated porous medium has been described. The main aim in the analysis is to study the effect of stratification on non-Darcian free convection flow and heat transfer. The solutions are obtained by perturbation technique and the resulting ordinary differential equations are solved numerically. It is found that the heat transfer is significantly affected by the modified Grashof number and the stratification parameter.

Natural convection in a thermally stratified fluid saturated porous medium

Natural convection heat transfer results are presented for a vertical plate of finite length immersed in a fluid saturated porous medium. The ambient vertical temperature gradient is positive but the plate temperature is everywhere higher than that of the surrounding fluid. Solutions are obtained by series expansion about the leading edge of the plate. The effects of stratification parameter on local and overall heat transfer coefficients, velocity and temperature fields are studied.