Overflow on the Mackenzie Delta sea ice surface and the hydraulics of strudel flows

Abstract

The main objective of this study was to describe the overflow of freshwater onto the sea ice surface in the Mackenzie Delta and to investigate the hydraulic behaviour of the upwelling and strudel events. This study was performed from the analysis of data collected during field investigations, from satellite images and from experimental laboratory studies. A forecasting method using the water level in the Mackenzie River was formulated to predict the overflow initiation about five days before its occurrence. The physical modelling of a strudel flow through a circular hole established a relation between the overflow depth and the discharge coefficient. Velocity measurements of the free-surface vortex using an Acoustic Doppler Velocimeter found that velocities at the vortex’s core were influenced by its vorticity. Finally, predictions of maximum strudel scour, which are of great importance for the determination of burial depth of pipelines, were predicted from published impinging jet experiments.