The structure of anomalous entry flow patterns through a planar contraction

Abstract

The structure and origin of the so-called bundle-like streams which are generated near the salient corners in unstable planar entry flows of rather dilute polyacrylamide solutions have been studied. The flow visualization experiments using the dye-solution injection technique clearly show that a bundle consists of two counterrotating vortex tubes, i.e. Goertler vortices whose cross-section is almost rectangular.