Effects of polymer additives on the large scale structure of a two-dimensional submerged jet

The large structures on the boundary of a two-dimensional submerged jet were examined. In the first experiment, a jet of a 100 ppm aqueous polyacrylamid solution was fed into pure water (P/W). In the second experiment, the jet as well as the ambient fluid were pure water (W/W), whereas in the third experiment, polymer solution (W/P) was in the ambient only.The large structures were found to be of the same size for all three experiments. The spread-angle was lowest for P/W and highest for W/P. These effects are attributed to a strong flow which stretches the polymer molecules in the mixing layer.