  This paper was originally published in June 2013 in JFM (vol. 725). There was
one result concerning an expression of viscous dissipation in convective flows
and a second result on the condition of applicability of the anelastic liquid
equation ($\gamma - 1 \ll 1$). We then found that this second result was wrong
and the explanation why this is so was published as a corrigendum in July 2014
in JFM (vol. 751). In a few words, the origin of the error is that we have
derived an expression for dissipation in the framework of the exact equations
and subsequently used it in the framework of the anelastic models. Here we have
included the original article, followed by its corrigendum.
