Why do turbulent eddies transport momentum faster than molecular motion alone?

Turbulent eddies transport momentum faster than molecular motion alone because eddies are large, multimolecular aggregates of fluid that mix together significant masses of fluid. In contrast, molecular motion involves the slower migration of individual molecules between fluid layers.12

In laminar flow, momentum transfer occurs through molecular friction (viscosity). However, when flow becomes turbulent, eddies form, disrupting smooth layers. These eddies create erratic motions that superimpose on the bulk flow, leading to a much greater rate of momentum transport than what can be explained by viscosity alone. This enhanced transport is represented by the austausch coefficient.13