Local Dynamic Similarity Model of
Cross-Ventilation
Part 2 - Application of Local Dynamic Similarity Model
Masaaki Ohba1,
Takashi Kurabuchi2,
Tomoyuki Endo3, Yoshihiko Akamine3, Motoyasu Kamata3,
Aya Kurahashi1
1Tokyo
Polytechnic
University, 2
Tokyo
University
of Science, 3
University
of
Tokyo
Abstract
The
proposed local dynamic similarity model of cross-ventilation predicted
ventilation flow rates more accurately than the conventional orifice flow model
assuming constant discharge coefficients when discharge coefficients actually
decreased with change of wind direction. This model was used to develop a new
method for evaluating the ventilation performance of window openings. The
obstructive effect of model size on flow fields in a wind tunnel was avoided by
installing the opening parallel to the wind tunnel floor. The ventilation
performance for various types of inflow openings was assessed by the ventilation
performance evaluation system. The discharge coefficient was expressed by an
approximate expression using dimensionless room pressure PR*. A
ventilation performance database was thus produced. For the field experiment in
a full-sized house, it was found that about 60% of all wind data were in the
range of |PR*| < 5. This reveals that the discharge coefficient
decreases frequently in actual wind.
Key
words: local dynamic similarity
model, ventilation flow rate, inflow opening, outflow opening, total pressure,
simplified measurement, ventilation performance, database.
|
