Product Code: JLA_1_3_44

Authors:
David T. Walker
William G. Tiederman
School of Mechanical Engineering, Purdue University, West Lafayette, Indiana 47907, U.S.A.

Inability to predict the high Schmidt number mixling of a concentrated polymer solution injected into a channel flow of water motivated the development of a method for measuring the product of the velocity fluctuation normal to the wall and the fluctuation in the polymer concentration. Time‐resolved concentration measurements were obtained using a laser‐induced fluorescence technique. The injected fluid was marked with a fluorescent dye and the spatial distribution of the intensity of fluorescent light emitted from an argon‐ion laser beam directed normal to the channel wall was measured with a line‐scan camera. Concentration of the injected fluid was inferred from the dye concentration. A dual scatter, helium‐neon laser Doppler velocimeter traversed along the line of the concentration measurements was used to measure the velocity normal to the wall. Successful implementation of this technique required very rapid sampling of the output from the line‐array camera as well as a large addressable random access memory. Instantaneous and time‐average results have been obtained for the injection of both water and a 700 ppm aqueous solution of SEPARAN AP‐273 into fully developed channel flows of water at a Reynolds number of 42,800.