Convection

Convection is the physical phenomenon that involves heat exchange through two systems at different temperatures, where at least one of them is fluid, and develops on the fluid medium in proximity to the separating surfaces.
Convection heating is derived from the transfer of heat by the movement of liquids or gases between surfaces. In a heating procedure by oven, hot gas and flame heat are transferred by convection of the heated gases and liquids to the surface of material to be heated.

Convection in a horizontal layer of an isotropic fluid heated from below is well known as the Rayleigh-Bènard convection. This phenomenon is, however, modified dramatically in the case of NLCs. When n is perpendicular to the temperature gradient, a new mechanism involving heat focusing, due to the anisotropy of the heat conductivity comes into play. It leads to a periodic horizontal heat current component, yielding a buoyancy force and flow. Due to the coupling between flow and n, small director perturbations will be enhanced and the instability sets in, in the form of periodic, roll structures (vortices).

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S. Bruschi, A. Ghiotti, Comprehensive Materials Processing, 2014.

Andrew J. Jefferson, ... Hom Nath Dhakal, Repair of Polymer Composites, 2018.

Ágnes Buka, Nándor Éber, Reference Module in Materials Science and Materials Engineering, 2018.