General aspects of turbulence and drag reduction

A new approach toward the origin of turbulence has been developed recently. In this theory, the key concept is the entropy of the flowing liquid. Any liquid in flow is characterized by a lower entropy than the liquid at rest. It can therefore be considered as more organized when flowing. Turbulence is treated as the loss of some of this organization. The theory is particularly applicable to drag reduction. The effect of a polymer in solution can be followed from very small concentrations (where it exhibits a stabilizing effect in drag reduction) up to very high concentrations (where in contrast it has a stabilizing influence on the flow). Through this new approach, the discrepancy between the two treatments of drag reduction represented by Astarita and Virk can be overcome. These two quite different theories (the one taking the maximum relaxation time of a polymer molecule as critical parameter, the other the size of the molecule) become complementary in our approach and are subsumed under a more general principle