DRAG REDUCTION BY POLYMER ADDITION
The reduction of flow friction drag through polymer addition, a phenomenon first subjected to systematic study has been the subject of very extensive research during the last decade. However, despite the combined efforts of specialists from many different fields, no satisfactory explanation of the phenomenon has as yet been found. Drag reduction has been observed with a large number of additive-fluid combinations, the most effective ones being high-molecular-weight linear polymers (such as polyethyleneoxide) in water. There are clear experimental indications that drag reduction is associated with a modification of the turbulence structure, and this is most remarkable in view of the permanence and statistical stability exhibited by ordinary Newtonian shear flow turbulence. Therefore, the phenomenon of drag reduction becomes of interest not only because of the promising technical applications it offers but just as much for fundamental fluid mechanical reasons. In this review of the subject, special attention is paid to the changes in turbulence structure brought about by the additivies, and an effort is made to understand these in the light of recent advances in the study of shear flow turbulence in ordinary fluids. Also, a simplified theoretical model of shear flow wall turbulence is presented, with the aid of which an exploratory study of the influence of some non-Newtonian fluid properties is carried out.
- Published also in Applied Mechanics, Proceeding of International Congress of Theoretical and Applied Mechanics (13th), Moscow, Aug 72, pp 177-198, 1973.
Massachusetts Institute of TechnologyDepartment of Aeronautics and Astronautics, 77 Massachusetts Avenue
Cambridge, MA United States 02139
- Landahl, M T
- Publication Date: 1972
- Pagination: 26 p.
- TRT Terms: Additives; Drag; Flow; Polymers; Shear stress; Turbulence; Walls
- Candidate Terms: Turbulent flow
- Old TRIS Terms: Drag reduction; Polymer additives; Wall shear stress
- Subject Areas: Design; Marine Transportation;
- Accession Number: 00098209
- Record Type: Publication
- Source Agency: National Technical Information Service
- Report/Paper Numbers: AFOSR-TR-74-1892 Intrm Rpt.
- Files: TRIS
- Created Date: Aug 13 1975 12:00AM