Experimental investigation was carried out to study the flow fields of the outlet hole in two confined passages with different staggered jet arrangement.Detailed flow field measurements were conducted with a five-hole probe.The influence of jet arrangement on the flow field and discharge coefficient of the outlet hole was investigated.Experimental data show that the jet arrangement has little influence on flow behavior in the passage of low aspect ratio

but play important role on discharge coefficient.Distinctively different flow transformation was found when the aspect ratio increased to 3 and 5

while the variation of discharge coefficient showed similar results.