Flow Characteristics in Two-Dimensional Expansions

Flow patterns for recirculating flows in sudden two-dimensional expansions have been obtained by numerical approaches and experimental studies. Analytical results for low expansion ratio of 1.25 are in good agreement with those of experimental findings. For larger expansion ratios, experimental findings reveal that the flow patterns are asymmetric and unstable. Two distinct types of flow occur in which the flow characteristics are almost the mirror image of one another in each type of flow. For large expansion ratios, turbulence develops peak values early and also decays at faster rate after the points of reattachment. Flow attains symmetric conditions earlier for larger expansion ratios.