Classical and symmetrical horizontal convection: detaching plumes and oscillations

Classical and symmetrical horizontal convection is studied by means of direct numerical simulations for Rayleigh numbers up to 3 x 10(12) and Prandtl numbers , 1 and 10. For both set-ups, a very good agreement in global quantities with respect to heat and momentum transport is attained. Similar to Shishkina & Wagner (Phys. Rev. Lett., vol. 116, 2016, 024302), we find Nusselt number versus scaling transitions in a region . Above a critical , the flow undergoes either a steady-oscillatory transition (small ) or a transition from steady state to a transient state with detaching plumes (large ). The onset of the oscillations takes place at and the onset of detaching plumes at . These onsets coincide with the onsets of scaling transitions.