Some developments in turbulence modeling for wind and environmental engineering

We present an overview of some developments in accommodating Reynolds-averaged Navier-Stokes (RANS) models to better predict complex high Reynolds and high Rayleigh number industrial and environmental flows. Considered are several novel modifications introduced into the second-moment and the eddy-viscosity framework. The treatment of wall boundary conditions is then discussed with focus oil a recently proposed robust integration up to the wall (ItW), a generalization of the standard wall functions (GWF), and a compound wall treatment (CWT) that combines both of the concepts. Arguing that large-eddy simulation (LES) will not for long be reliable and convenient for large-scale industrial and environmental computations, we consider the transient RANS approach to flows subjected to strong forcing, as well as combing RANS with LES. Several controversial issues and approaches in hybrid RANS/LES are discussed. Various concepts and improvements are illustrated by examples of wind- and buoyancy-driven environmental flows. (c) 2008 Elsevier Ltd. All rights reserved.