Transport by capillary waves: Fluctuating Stokes drift

Measurements of dye transport by /Idisordered capillary waves (generated by the Faraday instability) are reported as a function of the wave amplitude. The transport is diffusive, with effective diffusion coefficients that are typically at least a factor of 10³ larger than the molecular values. A model based on fluctuations in the Stokes drift caused by the disordered surface waves is tested and found to predict diffusion coefficients of the right order of magnitude, but roughly a factor of 3 too small. Residual correlations in the wave field are suggested to account for this discrepancy.