A model has been developed using the general-purpose Navier-Stokes solver CFX4 to
simulate Atmospheric Boundary Layer flow over complex terrain. This model has
been validated against the measured data from the Askervein Hill experiment, and has
been shown to perform well. The CFD model is also compared to the WAsP linear
model of wind flow over topography, and a significant improvement is noted for flow
over complex topography. Boundary conditions, gridding issues and sensitivity to
other solver parameters have all been investigated.
An advanced roughness model has been developed to simulate flow over forest
canopies, using a resistive body force within the canopy volume. The model is
validated against measured data for simple 2D cases, and for a complex 3D case over
real topography. The model is shown to give a more physically realistic profile for the
wind speed in and just above forest canopies than the standard roughness length
model used in most CFD simulations.
An automated methodology for setting up CFD simulations using the models
described has been developed. A custom pre-processing package to implement this
has been written, to enable the use of the CFD methodology in a commercial
environment
