ELECTRICAL FLUCTUATIONS AND ENTRY FLOW INSTABILITIES DURING CAPILLARY FLOW OF ELASTIC POLYMER SOLUTIONS.

This thesis is an experimental account of measurements of electrical fluctuations (noise) during capillary flow of polymer solutions, primarily aqueous solutions of poly(ethylene oxide). In general, the noise level increases with the flow rate. Within certain ranges of flow rate, two sets of harmonic peaks appear in the spectra. The fundamental frequency of the set that appears at lower frequencies, changes relatively little with the flow rate. The frequency components of the unstable entry flow were obtained by optical means. The noise method is shown to be a simple and powerful means of studying entry flow instabilities.