Rayleigh–Bénard convection in non-Newtonian fluids: Experimental and theoretical investigations
نویسندگان
چکیده
We present an experimental and theoretical study of Rayleigh–Bénard convection in shear-thinning fluids with temperature-dependent properties. Experiments were performed using a cylindrical cell radius R̂=60 mm height adjustable at d̂=15 20 giving radius-to-height ratio L = 4 3, respectively. The used are glycerol (Newtonian fluid) aqueous xanthan gum solutions (shear-thinning fluids) 1000 1200 ppm. Convection patterns visualized by the shadowgraph method. In part this study, weakly nonlinear analysis Varé et al. [J. Fluid Mech. 905, A33 (2020)] is extended to take into account variation thermal expansion coefficient temperature. For used, temperature dependence fluid parameters sufficiently strong obtain hexagonal cells onset convection. It has been observed that their size decreases increase difference across layer above critical value. This result provides support our where it shown for hexagons, band stable wavenumbers bent toward higher wavenumbers. glycerol, Newtonian large Prandtl number, slight wavelength rolls agreement literature.
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ژورنال
عنوان ژورنال: Physics of Fluids
سال: 2021
ISSN: ['1527-2435', '1089-7666', '1070-6631']
DOI: https://doi.org/10.1063/5.0070983