Polymer solution and fiber suspension rheology and their relationship to turbulent drag reduction

It is shown that the rheological behavior of dilute polymeric solutions can be described, at least semi‐quantitatively, by means of an equation containing a single viscosity coefficient and a single time constant. This expression and the Batchelor equation for suspension rheology are used to predict the major drag‐reduction phenomena observed experimentally. It is shown that mixed polymer‐fiber systems may be much more effective in their drag reduction capabilities than is either kind of additive when used alone. This latter prediction finds its qualitative verification in drag coefficients which are several‐fold lower than those observed at the asymptote of ’’maximum’’ drag reduction in polymer solutions.