On the gravitational suppression of hydrothermal modes in liquid layers with a blockage on the bottom wall

Lappa, Marcello (2019) On the gravitational suppression of hydrothermal modes in liquid layers with a blockage on the bottom wall. International Journal of Thermal Sciences, 145. 105987. ISSN 1290-0729 (https://doi.org/10.1016/j.ijthermalsci.2019.105987)

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Abstract

The present analysis follows and integrates author's previous work (Lappa M., 2017, Int. J. Thermal Science, 118: 303–319), where the main focus was on buoyancy flow of semiconductor and superconductor melts in geometries with an obstruction located on the bottom. Here we consider hybrid thermogravitational/thermocapillary convection in the case of high-Pr materials for which typical disturbances are represented by the so-called hydrothermal waves. By means of two-dimensional and three-dimensional numerical simulations, we show that the presence of a blockage in the physical domain can significantly change the dynamics of these waves in some regions of the space of parameters. More precisely, their velocity of propagation can be modulated and even reduced to zero. In the latter case, rolls travelling in the system are replaced with disconnected segments of stationary waves originating from the stations where sudden variations of the geometry occur.

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