| Summary: | 碩士 === 淡江大學 === 水資源及環境工程學系 === 86 === In order to investigate environmental wind field problem
caused byhigh-rise buildings,a series of wind tunnel experiments
were carried out on asmall scale model of the Taipei
metropolitan area . Data of wind velocity and wind direction
during five different situations -daytime , nighttime , the
wholeday , summer , and winter, and seven acceptable criteria
for comfortabilitywere used . Based on these , we tried to
estimate the comfort criteria prior toand after construction.
According to experimental results , the comfort criteria varies
as different meteorological data is used . It is most
appropriate to use wind velocity and direction data of the whole
day when setting the criteria for the average street . But in
special areas , the proper data depend on the time ofuse.there
is an obvious change in the environmental wind field after
theconstruction of high-rise buildings . In general , the
pedestrian - level meanand fluctuating wind velocities increase
, with only a few exceptions where they decrease . The
increase in wind velocity results from the channel effect caused
by the decrease in space which is taken up by the building . On
the other hand , the building may shield certain areas from the
wind , thus resulting in a decrease in wind velocity . The
comfort criteria obtained from the mean wind velocity data and
that obtained from the fluctuating wind velocity data vary .
This indicates that the wind velocity in an area may be low but
filled with strong fluctuations. Therefore , when evaluating the
comfort criteria of an area , the appropriate wind velocity and
direction data should be used and both the mean and fluctuating
wind velocites should be considered.
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