The Impact Of Air-Flow Separation On The Drag Of The Sea Surface

摘要: An approach that allows assessment ofthe impact of air-flow separation (AFS) fromwave breaking fronts on the sea-surface drag is presented. Wave are modelled by discontinuities slope. It assumedthat dynamics AFS from wave crests similar to thatfrom backward facing step. The form supported an individualbreaker described action pressure drop distributed alongthe forward face front. total stress due isobtained as a sum contributions different scales.Outside sea surface theviscous and wave-induced stress. To calculate stressdue physical model wind-wavespectrum used. Together with air flow in termsof stresses it forms self-consistent dynamical system for seasurface-atmosphere where wind waves strongly coupled.Model calculations coefficient agree measurements. shownthat dimensionless Charnock parameter (roughness length normalized onthe square friction velocity acceleration gravity)increases increase speed agreement fieldmeasurements. thefriction proportional cube speed. At low windsthe viscous dominates drag. role drag,which stress, isnegligible. moderate high winds dominates. windspeeds higher than 10 m s-1 becomescomparable supports up 50% totalstress.