کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
657447 1458063 2014 10 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
On Gill’s stability problem for non-Newtonian Darcy’s flow
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی جریان سیال و فرایندهای انتقال
پیش نمایش صفحه اول مقاله
On Gill’s stability problem for non-Newtonian Darcy’s flow
چکیده انگلیسی

Gill’s stability problem is the analysis of the parallel buoyant flow in a vertical porous channel whose parallel walls are kept at different uniform temperatures. Gill’s classical paper [Journal of Fluid Mechanics, 35 (1969) 545–547] provides a rigorous proof that this flow is linearly stable. The aim of our study is to extend Gill’s analysis to the class of non-Newtonian viscous fluids modelled by Ostwald-de Waele power law. The main difference between Newtonian fluids and general power-law fluids is that the basic velocity profile is linear, in the Newtonian case, and nonlinear with an inflexion point at the mid-plane, in the non-Newtonian case. Despite the presence of the inflexion point, this study evidences a stable behaviour of the basic flow versus general normal mode perturbations: longitudinal, oblique and transverse rolls. Stability to longitudinal rolls is proved analytically, while the behaviour of transverse and oblique rolls is investigated numerically. The damping rates of perturbations, evaluated for oblique and transverse rolls, display increasing values as the Darcy–Rayleigh number increases. Numerical data thus suggest that linear stability holds for the whole class of power-law fluids.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: International Journal of Heat and Mass Transfer - Volume 79, December 2014, Pages 759–768
نویسندگان
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