Drag-reducing fluids in a free turbulent jet

Article type: Research Article

Authors: Jackley, Donald N.

Affiliations: Underwater Ordnance Department

Abstract: To determine whether drag reduction is the result of turbulence dampening per se, the decay characteristic of a free turbulent jet was investigated. The work was suggested by recent boundary-layer studies showing that fluid drag reduction is caused by the presence of high-molecular-weight polymers in solution. The jet, having all the properties associated with turbulence except those caused by the presence of a wall, provided an ideal tool for the experiment. It was found that in a water solution of drag-reducing polymer, shear stress was reduced in the nozzle but not in the free jet. Drag reduction was therefore concluded to be a phenomenon of the wall because the character of the turbulence that is beyond the influence of the wall resembles the character of the turbulence in a free jet, which was found to be unaffected by the drag-reducing agent.

DOI: 10.3233/ISP-1967-1415204

Journal: International Shipbuilding Progress, vol. 14, no. 152, pp. 158-165, 1967