@article {183816,
	title = {Mechanisms of mean flow formation and suppression in two-dimensional Rayleigh-B{\'e}nard convection},
	journal = {Physics of Fluids},
	volume = {26},
	year = {2014},
	pages = {054104},
	abstract = {Two-dimensional laminar roll convection is capable of generating energetic horizontalmean flows via a well-understood process known as the tilting instability. Less wellunderstoodis the physical mechanism behind the strong dependence of this effecton the horizontal lengthscale of the convection pattern. Mean flows of this type havebeen found to form for sufficiently large Rayleigh number in periodic domains with asmall aspect ratio of horizontal length to vertical height, but not in large aspect ratiodomains.We demonstrate that the elimination of the tilting instability for large aspectratio is due to a systematic eddy-eddy advectionmechanism intervening at linear orderin the tilting instability, and that this effect can be captured in a model retaining twononlinearly interacting horizontal wavenumber components of the convection field.Several commonly used low-order models of convection also exhibit a shutdown ofthe tilting instability for large aspect ratio, even though thesemodels do not contain theeddy-eddy advection mechanism. Instability suppression in such models is due to adifferent mechanism involving vertical advection.We showthat this vertical advectionmechanism is excessively strong in the low-order models due to their low resolution,and that the instability shutdown in such models vanishes when they are appropriatelyextended.},
	author = {Fitzgerald, J. G. and Farrell, B. F.}
}
