Reattachment flow issuing from a finite width nozzle. IV Effects of aspect ratio of the nozzle

From the experimental flow visualization results of a reattachment flow from a 25 mm width nozzle at various aspect ratios, the influence of nozzle shape, Reynolds number, and initial turbulence intensity on flow behavior is determined. As the aspect ratio of the nozzle becomes smaller than 3, side plates cause the behavior of the flow to change considerably; the calculated results for a two-dimensional reattachment flow are no longer valid. For flow having an aspect ratio smaller than 2, it is found from the reattachment distance and the bubble pressure that reattachment weakens rapidly. A new correction factor is introduced as a function of aspect ratio, offset ratio, and Reynolds number. Thus the reattachment distance can be given for aspect ratios larger than 0.5 and smaller than 2, except for relatively offset ratios.