Consolidation of fresh ice ridges for different scales

Evgenii Salganik,Knut Vilhelm Høyland,Sönke Maus

doi:10.1016/j.coldregions.2019.102959

Evgenii Salganik, Knut Vilhelm Høyland + Show 1 more

Open Access

https://doi.org/10.1016/j.coldregions.2019.102959

Copy DOI

Abstract

This study characterizes the refreezing process of deformed ice. Twenty laboratory experiments in ice ridge consolidation were conducted to study the influence of ridge blocks size, initial temperature, and top surface roughness on the consolidation rate. Experiments covered a ridge block thickness range of 2–6 cm, initial block temperatures from −1 °C to −23 °C, ridge sail height up to 3 cm, and consolidated layer thickness up to 14 cm. Experiments were conducted with the average value of the convectional heat transfer coefficient of 20 W/m2K. The presented analytical model for ridge solidification was able to predict the observed ice growth rates and differences between level ice and consolidated layer thicknesses at different stages of the experiments. For the provided experiments, the consolidated layer was as much as 2.2–2.8 times thicker than the surrounding ice level. The consolidation rate was lower than in the analytical solution at the start of the experiment and approached the analytical solution only when the thickness of the surrounding level ice was larger than the ridge void width. The developed numerical model confirmed the observed experimental effects from the block size, initial temperature and surface roughness. Both numerical and analytical models can predict solidification rates for previous studies at the large range of scales for both fresh and saline ice. The advantages of the simplified experimental ridge geometry include high accuracy of the main parameters governing the process, including the ridge macroporosity.

Highlights

IntroductionDue to cooling from the atmosphere, the keels consolidate by freezing of these voids, largely proceeding vertically downwards and forming the consolidated layer (Leppäranta et al, 1995)
Level ice growth It is quite common that experiments focused on level ice growth provide results that deviate from theoretical predictions when plotted against FDD or∫ (Tf − Ta)dt
The usage of FDD for experimental comparison results in an increasing error and is more practical to avoid the conversion from level ice thickness to FDD and back to the consolidated layer thickness (Fig. 7b)

Summary

Introduction

Due to cooling from the atmosphere, the keels consolidate by freezing of these voids, largely proceeding vertically downwards and forming the consolidated layer (Leppäranta et al, 1995). This layer may be thicker than the surrounding level ice and constitutes a threat to the marine, coastal or hydraulic infrastructure, such as bridges, pipelines, lighthouses, range markers, fixed and floating facilities for production of oil and gas or offshore wind, harbours and ships. Leppäranta et al (1995), Blanchet (1998), Høyland (2002), Strub-Klein and Høyland (2011) described the seasonal development of the consolidated layer

Methods

Results

Discussion

Conclusion