Various issues in turbulent thermal convection

Thermal convection, which has attracted much attention in the past two decades, is a common phenomenon occurring in nature and in many engineering applications. Despite extensive studies of various aspects of convection, our knowledge about its nature remains incomplete. This paper presents an overview of new advances in the studies of turbulent thermal convection mainly from four areas: turbulent heat transport, coherent structures, large-scale circulation, and turbulent fluctuations in small-scale turbulence.