Thermal convection: patterns, evolution and stability, by M. Lappa

Free thermal convection driven by nonlocal effects.

We report and explain a convective phenomenon observed in molecular dynamics simulations that cannot be classified either as a hydrodynamics instability nor as a macroscopically forced convection. Two complementary arguments show that the velocity field by a thermalizing wall is proportional to the ratio between the heat flux and the pressure. This prediction is quantitatively corroborated by o...

New Stability Results for Long–Wavelength Convection Patterns

We consider the transition from a spatially uniform state to a steady, spatiallyperiodic pattern in a partial differential equation describing long-wavelength convection [1]. This both extends existing work on the study of rolls, squares and hexagons and demonstrates how recent generic results for the stability of spatially-periodic patterns may be applied in practice. We find that squares, eve...

Stability of hexagonal patterns in Bénard-Marangoni convection.

Hexagonal patterns in Bénard-Marangoni (BM) convection are studied within the framework of amplitude equations. Near threshold they can be described with Ginzburg-Landau equations that include spatial quadratic terms. The planform selection problem between hexagons and rolls is investigated by explicitly calculating the coefficients of the Ginzburg-Landau equations in terms of the parameters of...

Convection patterns: Time evolution of the wave-vector field.

‏‎suppression of coke formation in thermal cracking by coke inhibitors‎‏

‏‎the main purpose of this research was to:1.develop a coking model for thermal cracking of naphtha.2.study coke inhibition methods using different coke inhibitors.developing a coking model in naphtha cracking reactors requires a suitable model of the thermal cracking reactor based on a reliable kinetic model.to obtain reliable results all these models shall be solved simultaneously.for this pu...