| 摘要 |
PROBLEM TO BE SOLVED: To make it possible to calculate the maximum value of the unit-time average concentration of a tracer gas simply by dividing the fluctuation range of the wind direction in the direction of a main airflow, obtaining the unit-time average-concentration component from the average gas-concentration distribution, which is measured in every wind direction in a short time, and extracting the maximum value. SOLUTION: The (x) axis is set in the direction of a main airflow, passing the position of a chimney model 2 in a wind tunnel, which is a gas source, andθcoordinates are set in the direction perpendicular to the (x) coordinate axes with the chimney 2 as the center for every coordinate of a plurality of the (x) coordinates xj (j=1, 2, 3...). The average gas- concentration distribution Ct0 for three minutes at every point (xj ,θ) is obtained. Then, the fluctuation range of the wind direction is divided into a plurality of the wind directionsϕi (i=...-1, 0, -1...) for every coordinate of a plurality of the (x) coordinates xi . It is assumed that the concentration distribution Cti at each wind directionϕi is approximately equal to the three-minute average gas-concentration distribution at the wind directionϕ0 in the direction of the (x) axis. Each concentration distribution Cti is weighted by the appearance frequency, and the 1-hour average concentration distribution CHi (xi ,θ) is obtained. Then, the maximum value among them is extracted as the maximum ground-surface tracer-gas concentration.
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