抄録
As a result of the characteristics of the flow structure of plane jet from push-pull local ventilation systems, we reached the conclusion as follows. At first, in the region close to the nozzle, the maximum value of the mean velocity of jet goes down with downstream distance and the distribution spread upward and downward. The distribution profile of velocity u^^- and v^^- develops forming similar figure when X_1/L=0.34. The relative turbulence intensity profile of u' and v' shows the similar tendency and the position of the peak value moves from y_1/b_<1/2>=1 to y_1/b_<1/2>=0.8 with down stream distance. Secondary, in the region close to the exhaust hood, the mean velocity distribution in the axial direction is almost identical to the gauss distribution when y_1/b_<1/2><1. However, when y_1/b_<1/2>>1, the distribution moves upward from the gauss distribution. When it comes to the relation turbulence intensity profile, the value is lower than the results by Gutmark et al. As it gets close to the exhaust hood, the relative value of u^^-/u^^-_m increases because the value u^^-_m goes down, resulting in unclear peak point. Thirdly, the maximum value of mean velocity on the central axis goes down with downstream distance. That result is almost identical to that by V.W. goldschmidt et al. When the half-velocity points are almost identical to the relation expressions by Gutmark et al. until X_1/2B_1=8, however, when it comes to the downstream below that, the value increases under the influence of the exhaust.
