Turbulent flow over isolated ridges; influence of vegetation

The NCAR large-eddy simulation (LES) code has been converted to use a conformal mapping to transform Cartesian coordinates into a flat computational space. Using this newly developed tool, we will present an investigation of turbulent flow over isolated rough ridges. Comparisons will be made between runs with a specified roughness length and runs resolving the influence of a forest canopy. Observations from wind tunnel simulations will provide support for the numerical results. The interplay between pressure drag induced by the ridge and that by the vegetation will be discussed.