Lock-release inertial gravity currents over a thick porous layer

Abstract

This paper examines the motion of a dense fluid that develops as an inertial gravity current of decreasing mass above a horizontal porous bed, while flow described by Darcy's law occurs in the bed. Measurements of the mass and the front position of the current in a set of laboratory experiments performed by changing different parameters are presented. The results are explained by means of a global analytical model that suggests practical correlations combining the parameters. Thus, previous experimental, numerical and theoretical findings are extended to describe lock-release gravity currents above more realistic porous beds.

Instabilities in a liquid film flow over an inclined heated porous substrate

“…The value B ¼10 as considered in Goussis and Kelly (1991) is taken to validate the results in the absence of experimental data for heat transfer coefficients at liquid-gas interfaces. The value of the permeability parameter, b 0 is based on the experimental conditions set up by Thomas et al (2004) who used a porous substrate with porosity W ¼ 0:375 and particle diameter d 0 ¼ 0:00286 m. Setting h 0 ¼0.0024 m as the mean film thickness (Pascal, 2006), the permeability k of the porous medium is computed usingthe relation (Christopher and Middleman, 1965) k ¼…”

Instability of power-law fluid flow down a porous incline

“…The particular value of H is the maximum fluid thickness that results in a laminar flow down an impermeable slope with an inclination of θ = 0.1 rad. In order to obtain possible values for the parameters related to a porous bottom we resort to the experimental conditions set up by Thomas et al [6], who used a porous substrate with porosity Φ = 0.375 and particle diameter d = 0.00286 m. Using these values we can calculate the modified permeability associated with power-law fluid flow from the formula (see [12])…”

“…Much attention is being focussed on incorporating the effect of bottom permeability in the study of the spread of dense fluids under layers of lighter fluid, with the goal of obtaining more realistic models for gravity-driven flows over such surfaces as soil, river beds and layers of gravel. A summary of these investigations can be found in a recent paper by Thomas et al [6]. It should also be pointed out that the layer of fluid behind the head of a gravity current resulting from the spread of dense fluid down an incline is subject to instability.…”

Effect of permeability on the instability of a non-Newtonian film down a porous inclined plane

“…This has relevance in modeling environmental flows that mostly occur over porous surfaces. A summary of the investigations that consider the effect of bottom permeability in the study of the spread of dense fluids under layers of lighter fluid, with the goal of obtaining more realistic models for gravity-driven flows over surfaces such as soil, river beds and layers of gravel is presented in Thomas et al [40].…”