A Study on Anomalous Turbulent Flows of Non-Newtonian Fluids : 3rd Report, Experiment and Analysis in Transitional Region

Abstract

Transitional region of pipe flows of dilute polymer solutions is investigated. Experiment is made with HEC water solutions and the following results are obtained. Anomaly of the resistance coefficient is very small in the flow region before transition, though it is comparatively large for PEO solutions as reported in the previous paper. In this flow region a kind of fluctuations of static pressure is recognized and once the fluctuations occur, the appearance of issuing jets shows some anomalous winding effects. An approximate analysis is made on the anomaly of the resistance coefficient in the flow region before transition. The results show that the resistance coefficient becomes larger than that of Poiseuille flow and that if Reynolds numbers and the fluctuations are constant, the rate of increase of the resistance coefficient enlarges as Weissenberg number increases. Comparison between analytical results and experimental data shows an approximate agreement.