The flow behaviour over various two-dimensional (2D) urban-type surfaces was investigated in a
laboratory wind tunnel. Square aluminium bars of size 2.5 cm were used to represent flat-roof
buildings and the building separation was adjusted to fabricate various types of urban surface of
building-height-to-street-width (aspect) ratios of 1, 1/2, 1/8, 1/10 and 1/12. Mean velocities and
velocity fluctuations were measured with a 90o X–hotwire anemometry. The current results compare
well with our previous large-eddy simulation (LES). Analysis of the turbulence characteristics for
different urban surfaces was performed in attempt to examine the near-ground boundary layer
response to various street-canyon configurations.postprin
