Influence of background vertical motions on free convection over a thermally inhomogeneous horizontal surface

In a linear approximation the problem of the influence of background vertical motions on free convection over a thermally inhomogeneous horizontal surface has been solved analytically. The dimensionless number that determines this influence and that represents the ratio of the product of the characteristic velocity of background vertical motions and of the horizontal scale of thermal inhomogeneities to the coefficient of thermal diffusivity of the medium has been found. Descending motions may effectively suppress convection (not only decrease the height of penetration of convective motions into the medium but also to decrease their amplitude substantially). Ascending motions increase the height of penetration of convective motions into the medium and, to a lesser extent, the vertical component of convective velocity. © 2008 Springer Science+Business Media, Inc.