Article,
On the domain size for the steady-state CFD modelling of a tall building
WIND AND STRUCTURES, 15 (4): 313-329 (July 2012)
Abstract
There have existed for a number of years good practice guidelines for
the use of Computational Fluid Dynamics (CFD) in the field of wind
engineering. As part of those guidelines, details are given for the size
of flow domain that should be used around a building of height, H. For
low-rise buildings, the domain sizes produced by following the
guidelines are reasonable and produce results that are largely free from
blockage effects. However, when high-rise or tall buildings are
considered, the domain size based solely on the building height produces
very large domains. A large domain, in most cases, leads to a large cell
count, with many of the cells in the grid being used up in regions far
from the building/wake region. This paper challenges this domain size
guidance by looking at the effects of changing the domain size around a
tall building. The RNG k-epsilon turbulence model is used in a series of
steady-state solutions where the only parameter varied is the domain
size, with the mesh resolution in the building/wake region left
unchanged. Comparisons between the velocity fields in the near-field of
the building and pressure coefficients on the building are used to
inform the assessment. The findings of the work for this case suggest
that a domain of approximately 10\% the volume of that suggested by the
existing guidelines could be used with a loss in accuracy of less than
10\%.
