Effect of surface-active material on the damping of gravity waves: A reappraisal

Abstract Calculations on wave properties for gravity waves have shown that their damping coefficient can be considerably increased by the presence of surface-active material. The potential increase in damping is larger than that for short wavelength capillary waves, but the surface dilational modulus required to give a noticeable effect increases with increasing wavelength of the gravity waves. In practice-with a proper choice of surface-active material-effects on waves of up to 1 m wavelength can be expected. A reassessment of the old technique of wave calming by spreading of oil is advocated and some instances are mentioned in which it is expected to have a beneficial effect.