Formation of Capillary Ripples on Gravity-Capillary Waves.

Abstract

Parasitic capillary ripples emerging on the forward face of wind-driven gravity-capillary waves are investigated experimentally. The wave slope angle is measured optically with sufficient time and space to characterize short ripples. The condition of ripple generation and the ripple steepness are correlated with the amplitude, the degree of fore-aft asymmetry, and the maximum local curvature of the underlying gravity-capillary waves. The phase speed of the gravity-capillary waves carrying ripples can be correlated with the characteristic parameter of ripples. These characteristics do not explicity depend on the wind velocity over the waves.