The unstable nature of buoyant flow in a vertical porous slab with a pure conduction temperature distribution is investigated. The permeable and isothermal boundaries are subject to a temperature difference, which is responsible for the basic stationary and parallel vertical flow in the slab. The momentum transfer is modeled by adopting the Darcy-Forchheimer law, thus including the quadratic form-drag contribution. The instability to small-amplitude perturbations is tested by parameterizing the basic stationary flow through the Darcy-Rayleigh number and the form-drag number. The modal analysis is carried out numerically with a pressure-temperature formulation of the governing equations for the perturbations. The neutral stability curves and the critical values of the wave number and of the Darcy-Rayleigh number are obtained for different prescribed values of the form-drag number.
On the onset of convection in a highly permeable vertical porous layer with open boundaries / Barletta A.; Rees D.A.S.. - In: PHYSICS OF FLUIDS. - ISSN 1070-6631. - STAMPA. - 31:7(2019), pp. 0741061.074106-0741061.074106. [10.1063/1.5110484]
On the onset of convection in a highly permeable vertical porous layer with open boundaries
Barletta A.
Membro del Collaboration Group
;
2019
Abstract
The unstable nature of buoyant flow in a vertical porous slab with a pure conduction temperature distribution is investigated. The permeable and isothermal boundaries are subject to a temperature difference, which is responsible for the basic stationary and parallel vertical flow in the slab. The momentum transfer is modeled by adopting the Darcy-Forchheimer law, thus including the quadratic form-drag contribution. The instability to small-amplitude perturbations is tested by parameterizing the basic stationary flow through the Darcy-Rayleigh number and the form-drag number. The modal analysis is carried out numerically with a pressure-temperature formulation of the governing equations for the perturbations. The neutral stability curves and the critical values of the wave number and of the Darcy-Rayleigh number are obtained for different prescribed values of the form-drag number.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.