Rayleigh Convection in a Fluid Heated Differentially at the Bottom

[摘要] Roll-type convection in a viscous Boussinesq fluid layer heated differentially at thebottom is numerically investigated by a spectral model. The differential heating along thebottom is assumed sinusoidal for the sake of simplicity.Results are summarized as follows: a) as the horizontal temperature gradient increases, Rayleigh convection cells tend to be deformed so that reinforced large (so-called) direct cellsand suppressed small indirect cells stand alternately; b) the horizontal temperature gradientacts to suppress the vertical heat transport due to convective rolls; c) as the horizontaltemperature gradient increases, the longer wave components of the spectrum tend to beintensified; d) when stable and unstable regions exist side by side, the Rayleigh-type convection seems to develop in the unstable region only if the width of the unstable regionexceeds that of Rayleigh convection cells in qualitative agreement with our experimentalobservations (Part I).

[学科分类] 大气科学