The effect of polymer additives on pressure pulsation in a boundary layer

Momentum, heat, and mass transfer analogy for drag-reducing solutions

“…Guided by these experimental findings, Dudukovic (1985) developed a model to illustrate the influence of the turbulent Schmidt number on mass transfer rates even in Newtonian solutions, and to show that the effect predicted by theory is small, and, hence, more of theoretical than practical interest. On the other hand, it was found experimentally (Fortuna and Hanratty, 1972;Makarenkov et al, 1973;Taylor and Middleman, 1974;Berman, 1978) that drag-reducing polymers not only decrease the turbulent intensity but also shift the turbulent spectra toward lower fequencies; i.e., the highfrequency portion of turbulent spectra is much more suppressed. As a consequence, in drag-reducing solutions both eddy viscosity and eddy mass diffusivity are reduced due to decrease in turbulent intensity.…”