Only lower flow regime occurs with aeolian transport. Thus grains lift higher and the tractive mode of transport known as saltation is more common in wind-blown sand than subaqueous flow. The momentum transfer is also greater in aeolian transport due to the absence of a water cushion and the higher saltation. Aeolian ripples are mostly straight to slightly sinuous in crest form with bifurcations along the crests. Entrainment and Transport by Waves Waves generate an orbital motion than extends downward in progressively smaller orbitals to a depth equal to half the wave length.
Ripples formed by waves are nearly symmetrical with a slight coarsening in the troughs.
Waves cause symmetrical ripples unless waves are near breaking, then asymmetrical ripples form as if flow were in the same direction as waves are moving. As orbital vel. increases, ripples give way to plane parallel beds of upper flow regime. Ice-transport load consists of mostly mud and all available coarser sizes. A slope and thus gravity are necessary for all gravity flows. Fluids play a secondary role of reducing friction between particles until the flow is well underway.