Hydraulic and turbulent flow characteristics beneath a simulated partial ice-cover

Abstract

A series of experiments were conducted beneath simulated partial ice covers to investigate the turbulent flow behaviour using a particle image velocimetry system. The velocity data were used to assess predictive capabilities of some bed shear stress models developed for open channels. Specifically, the abilities of the Ludwieg–Tillmann, quadratic stress law and Prandtl's seventh power law techniques to estimate the bed shear stress were compared to estimates from the logarithmic law technique. The ice coverage ratios considered were 0% (representing open water condition), 25%, 50% and 75%. Increasing ice coverage ratio to 50% and 75% increased the freestream velocity by approximately 8%. The dynamic role of secondary flow caused prevalence of the dip phenomenon under open water conditions and increased level of large-scale anisotropy. The present results depict easy adoption of the quadratic and Prandtl's seventh power laws to partial ice-covered flows.