TURBULENCE AND DRAG REDUCTION WITH POLYMER ADDITIVES

This thesis describes the research with drag reducing additives which was carried out on a part time basis between 1965 and the present date. As is inevitable with such a rapidly expanding field of study, between 85 and 90% of the published work of others in this field has occurred since the commencement of the present research. When the work was started surprisingly little was known about the drag reduction phenomenon in detail. At an early stage it was decided to attack the problem on a broad front in order to provide as much data as possible for likely practical applications and to throw light on the mechanism causing the effect. The initial approach had of necessity to be largely empirical. The work is concerned with internal flows through rough and smooth pipes, external flow over bluff bodies and other anomalous effects involving heat transfer cavitation and submerged jets. The thesis is conveniently presented in sections which are linked together with a general discussion. Many of the results herein have been previously published by the author in a number of scientific journals and symposia transactions. In some instances similar findings have been reported by other workers almost simultaneously, which is not surprising with such a rapidly developing topic. It is therefore very difficult to designate with certainty to any worker the priority for several of the discoveries. A collection of the publications by the author are presented in the flap at the end of this thesis, and the dates of publication will provide some indication of the time scale of the subject development during the course of this study.