Imbrication of Tabular Boulders

See related content

by Cyril Galvin,

Document Type: Proceeding Paper

Part of: Hydraulic Engineering

Abstract: Analysis of moments on tabular boulders projecting into a uniform stream indicates that a tabular boulder dipping downstream is unstable and can be overturned by velocities expected during storm flows. For a tabular, downstream-dipping, quartz boulder, at least half of which projects above mean bed level, there is a critical overturning Froude number, somewhat less than 3. 0. As a result of this instability, tabular boulders will preferentially dip upstream, overlapping the next downstream boulder where such boulders are abundant. Because this imbrication is a form of streamlining, imbrication, and related preferential orientation of isolated boulders, may explain observed overprediction of friction factor for flows in some mountain rivers.

Subject Headings: Boulders | Rivers and streams | River flow | Mountains | Fluid velocity | Storms | Froude number | Friction |

Services: Buy this book/Buy this article


Return to search