As such, our analysis conceptually precedes meandering behavior, and does not conflict with the detailed sedimentological and hydraulic studies available in the literature. We suggest that meandering in a broad range of systems is triggered by fundamental processes stemming from the dynamics of fluid flow that lead to local deceleration and development of an adverse pressure gradient within the flow. We thus explore the common cause of the instability behind all meandering systems, including rivers, the poster child of meandering. Yet, a universal criterion is lacking to explain meandering of rivers and other systems. Meandering is observed in glacial meltwater, the Gulf Stream, Jet Stream, submarine channels, free-falling streams of viscous fluid, and other systems in one, two and three dimensions, including derailed trains and jackknifed tractor trailer trucks. Rivers are only one of many fluid systems that exhibit meandering behavior, and no other involves sediment. It was recognized in the mid-20 th century that "no general theory of meanders is as yet satisfactory" and this remained the case to the present time. Previous formulations have characterized meandering as a response of a straight river to an imposed perturbation and comprehensively addressed meander development and morphology as well as the hydraulics internal to the various parts of meandering rivers, but not attempted to identify a universal cause of meandering itself. Historically, river meandering has been attributed to erodible banks and sediment transport.
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