RECENT DEVELOPMENTS IN 2ND-MOMENT CLOSURE FOR BUOYANCY-AFFECTED FLOWS

The paper summarizes a new type of second-moment closure, more elabora te in form than earlier versions but designed to satisfy the two-compo nent limit to which turbulence reduces at a wall or at a sharp density interface. Because they are intrinsically realizable, closures of thi s type are believed to offer the prospects of a wider range of applica bility than earlier schemes. They may also be expected to display bett er numerical stability. Several illustrative applications are provided including the downward directed warm jet, the stratified mixing layer and buoyancy affected grid-turbulence decay. Extension of the scheme to near wall flows appears possible without introducing empirical 'wal l-reflection' terms, at least in flows parallel to walls.