Separated Flow Through Large Sudden Expansions

Flow patterns for large, sudden expansions have been obtained experimentally. The experimental studies reveal that flow patterns for large expansions are highly asymmetric and unsteady. Two distinct types of flow have been observed in which the flow characteristics are essentially mirror images of each other. Turbulence develops peak values earlier and decays faster with increasing expansion ratios. Because of the increased turbulent mixing with increased expansion ratio, the mean flow pattern becomes steady and uniform more rapidly with increased expansion ratios. For the Reynolds number range 0.5 x 10⁵ to 1.0 x 10⁵, there is no Reynolds number influence on these flow patterns.