Direct numerical simulation of a turbulent forced buoyant plume in a crossfow is performed at a source Reynolds number Re 0 = 1000, Richardson number Ri0 = 1, Prandtl
number Pr = 1 and source-to-crossfow velocity ratio R0 = 1. The instantaneous and
temporally averaged fow felds are assessed in detail, providing an overview of the fow
dynamics. The velocity, temperature and pressure felds are used together with enstrophy
felds to describe qualitatively the evolution of the plume as it is swept downstream by the
crossfow, and the mechanisms involved in its evolution are outlined. The plume trajectory
is determined quantitatively in a number of ways, and it is shown that the central streamline
and the centre of buoyancy of the plume difer signifcantly—as with jets in crossfow, the
central streamline is seen to follow the top of the plume, whereas the centre of buoyancy,
by defnition, describes the plume as a whole. We then investigate the turbulence properties
inside the plume; in particular the eddy viscosity and difusivity are presented, which are
signifcant parameters in turbulence modelling. Assessment of turbulence production demonstrates the presence of regions where turbulence kinetic energy is redistributed to the
kinetic energy of the mean fow, implying a negative eddy viscosity within certain regions
of the domain. Similarly, the observation that the buoyancy fux and buoyancy gradient
are anti-parallel in specifc regions of the fow implies a negative eddy difusivity in said
regions, which must be realised in models of such fows in order to capture the countergradient transport of thermal properties. A characteristic eddy viscosity and difusivity are
presented, and shown to be approximately constant in the fully developed regime, resulting
in a constant characteristic turbulent Prandtl number, in turn signifying self-similarity.