Abstract
Basic flow characteristics were investigated for a circular wind tunnel with a 3/4 open-type test section. Its characteristics were exceptionally good; the uniformity of mean velocity is ±0.4%, turbulence intensity is 0.16% at the exit of its contraction nozzle and a statics pressure coefficient is 0.001/m along the center line of the test section. Meanwhile, since the final goal of the present research is to investigate the mechanism of pulsation flows generated in the test section, strong pulsation flows were generated and observed by the change of a streamwise distance between the contraction nozzle and the collector, a collector size and an inducement ratio into the collector.
