A generalized model of flow in meandering subaqueous and subaerial channels is
developed. The conservation equations of mass and momentum are depth/layer
integrated, normalized, and represented as deviations from a straight base state. This
allows the determination of integrable forms which can be solved at both linear and
nonlinear levels. The effects of various flow and geometric parameters on the flow
dynamics are studied. Although the model is not limited to any specific planform, this
study focuses on sine-generated curves. In analysing the flow patterns, the turbidity
current of the subaqueous case is simplified to a conservative density flow with water
entrainment from above neglected. The subaqueous model thus formally corresponds
to a subcritical or only mildly supercritical mud-rich turbidity current. By extension,
however the analysis can be applied to a depositional or erosional current carrying
sand that is changing only slowly in the streamwise direction. By bringing the
subaqueous and subaerial cases into a common form, flow behaviour in the two
environments can be compared under similar geometric and boundary conditions. A
major difference between the two cases is the degree of superelevation of channel flow
around bends, which is modest in the subaerial case but substantial in the subaqueous
case. Another difference concerns Coriolis effects: some of the largest subaqueous
meandering systems are so large that Coriolis effects can become important. The
model is applied to meander bends on the youngest channel in the mid-fan region of
the Amazon Fan and a mildly sinuous bend of the North-West Atlantic Mid-Ocean
Channel. In the absence of specific data on the turbid flows that created the channel,
the model can be used to make inferences about the flow, and in particular the range
of values of flow velocity and sediment concentration that would allow the growth
and downfan migration of meander bends.
Experimental Analysis on the Water Entrainment of Turbidity Current over a Mobile Bed
