DOI: 10.1615/ICHMT.2009.TurbulHeatMassTransf
ISBN Print: 978-1-56700-262-1
ISSN: 2377-2816
Numerical simulation of scalar dispersion in separated flows using algebraic flux models
ABSTRACT
We present a numerical study of passive scalar dispersion in turbulent separated flows to establish the predictive capabilities of algebraic flux models against the standard eddy-diffusivity representation. The scalar dispersion from a point source over a wavy wall is initially investigated to carefully evaluate scalar flux models using accurate DNS data. The roof-top release of a passive plume from a wall-mounted cube in a turbulent boundary layer is then presented to prove that algebraic models can also be applied successfully to atmospheric dispersion at street-scale. Despite the similarities with the standard gradient-diffusion hypothesis and the questionable validity of local-equilibrium conditions, the numerical experiments show that algebraic models provide a significant improvement for scalar dispersion simulations in complex flows with respect to the standard eddy-diffusivity model.