A brief review of transition processes of wave ripples

Abstract

Wave ripples forming under stable oscillatory-flow conditions have a particular set of morphologies, dimensions, and crest orientations. With any significant change in the hydraulic conditions, the wave ripples lose their original equilibrium configuration, take transient forms, and eventually attain a new equilibrium state. This transition process depends on ( ) the ratio of the wavelengths of the original ripples to the renewed equilibrium ripples (λ e /λ i ), ( ) the degree of asymmetry in oscillatory flow, and ( ) sediment grain size when a new oscillatory flow is perpendicular to the crest lines of pre-existing ripples. Distinctive transient ripples, which tentatively appear (and then disappear) during the period of modification, are likely to be preserved in the geological record when λ e /λ i < . The analysis of such ripples can benefit estimations of paleohydraulic conditions.