Frazil dynamics and precipitation in a water column with depth-dependent supercooling

Holland, Paul R.; Feltham, D. L.

doi:10.1017/s002211200400285x

Cited by 55 publications

(99 citation statements)

References 33 publications

(55 reference statements)

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“…Such models rely on previous theoretical work concerning frazil-ice dynamics, which was pioneered by Daly (1984). Models of frazilice dynamics have been applied to the study of frazil in the upper ocean Omstedt, 1994, 1998;Heorton et al, 2017) and also to the study of frazil ice beneath ice shelves (Jenkins and Bombosch, 1995;Khazendar and Jenkins, 2003;Smedsrud and Jenkins, 2004;Holland and Feltham, 2005;Jordan et al, 2014Jordan et al, , 2015. The theory of frazil-ice dynamics involves parameterizations of a number of physical processes that affect the evolution of a population of ice crystals.…”

Section: Frazil Ice In the Environmentmentioning

confidence: 99%

“…These papers are illustrative of a wider range of studies (e.g. Svensson and Omstedt, 1998;Khazendar and Jenkins, 2003;Holland and Feltham, 2005;Jordan et al, 2014Jordan et al, , 2015Wilchinsky et al, 2015;Smedsrud and Martin, 2015); recently it appears that growth law f 3 has been used most commonly, if not exclusively. In summary, numerical calculations show that there is only weak dependence on aspect ratio: f 1 is typically close to f 2 ; however, f 1 is some 10-100 times greater than f 3 , as illustrated in Fig.…”

Section: Crystal Growth Ratementioning

confidence: 99%

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Frazil-ice growth rate and dynamics in mixed layers and sub-ice-shelf plumes

Jones

Wells

2018

The Cryosphere

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Abstract. The growth of frazil or granular ice is an important mode of ice formation in the cryosphere. Recent advances have improved our understanding of the microphysical processes that control the rate of ice-crystal growth when water is cooled beneath its freezing temperature. These advances suggest that crystals grow much faster than previously thought. In this paper, we consider models of a population of ice crystals with different sizes to provide insight into the treatment of frazil ice in large-scale models. We consider the role of crystal growth alongside the other physical processes that determine the dynamics of frazil ice. We apply our model to a simple mixed layer (such as at the surface of the ocean) and to a buoyant plume under a floating ice shelf. We provide numerical calculations and scaling arguments to predict the occurrence of frazil-ice explosions, which we show are controlled by crystal growth, nucleation, and gravitational removal. Faster crystal growth, higher secondary nucleation, and slower gravitational removal make frazil-ice explosions more likely. We identify steady-state crystal size distributions, which are largely insensitive to crystal growth rate but are affected by the relative importance of secondary nucleation to gravitational removal. Finally, we show that the fate of plumes underneath ice shelves is dramatically affected by frazil-ice dynamics. Differences in the parameterization of crystal growth and nucleation give rise to radically different predictions of basal accretion and plume dynamics, and can even impact whether a plume reaches the end of the ice shelf or intrudes at depth.

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Section: Frazil Ice In the Environmentmentioning

confidence: 99%

Section: Crystal Growth Ratementioning

confidence: 99%

Frazil-ice growth rate and dynamics in mixed layers and sub-ice-shelf plumes

Jones

Wells

2018

The Cryosphere

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“…(ii) The ice production rate term (2.2) is probably adequate, to first order, for a slab of thin ice, but it does not capture the complexities of the thermodynamic growth of suspended frazil ice (e.g. Holland & Feltham 2005) or the consolidation of slush and ice rubble in the pile-up and new-ice regions (Marchenko 2008). (iii) The quadratic bottom stress (2.3), while apt for representing friction underneath consolidated ice, is not quite as suitable for a layer containing suspended frazil ice at low concentrations.…”

Section: Continuous Model Formulationmentioning

confidence: 99%

The opening of wind-driven polynyas

2014

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The opening of wind-driven coastal polynyas has often been investigated using idealised flux models. Polynya flux models postulate that the boundary separating the region of thin ice adjacent to the coast within the polynya from the thicker ice piling up downstream is a mathematical shock. To conserve mass, any divergence of the ice flux across the shock translates into a change in the shock's position or, in other words, a change in the width of the thin-ice region of the polynya. Polynya flux models are physically incomplete in that, while they conserve ice mass, they do not conserve linear momentum. In this paper, we investigate the improvements that can be achieved in the simulation of polynyas by imposing conservation of momentum as well as mass. We start by adopting a mathematically solid formulation of the ice mass and momentum balances throughout the polynya region, from the coast to the pack ice. Hydrostatic and plastic versions of the ice internal forces are used in the model. Two different approaches are then explored. We first postulate the existence of a shock at the seaward edge of the thin-ice region of the polynya and derive jump conditions for the conservation of ice mass and momentum at the shock which are consistent with the continuous model physics. Polynyas simulated by this mass-and momentum-conserving shock model always reach a steady state if the polynya forcing is uniform in space and constant in time. This is also true for all polynya flux models presented previously in the literature, but the location of the steady-state polynya edge and the time required to reach it can greatly differ between shock formulations and more simplistic flux ones. We next relax the assumption that a shock exists and let the boundary between thin ice and piling up ice emerge naturally as part of the full solution of the continuous model equations. Polynyas simulated in this way are very different from those simulated by either shock or flux models. Most notably, we find that steady-state polynya solutions are not always attainable in the continuous model. We determine under which conditions this is so and explain how such unsteady solutions come about. We also show that, in those cases when a steady-state solution exists in the continuous model, the steady-state polynya width is considerably larger than in the shock model, and the time required to attain it is accordingly longer. The occurrence of such significant differences between the polynya solutions calculated with flux and shock models, on the one hand, and with more sophisticated continuous † Email address for correspondence: mamm@noc.ac.uk

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“…[36,42,24,40,41,21], mainly based on Boussinesq-like approximation. More specifically, in this work we consider the mixture ice-sea water as a dense compressible fluids.…”

Section: Introductionmentioning

confidence: 99%

“…According to the Boussinesq approximation, the seawater density can be expressed by means of the following linearized equation of state, see e.g. [21] …”

mentioning

confidence: 99%

A Multiphase Model for the Numerical Simulation of Ice-Formation in Sea-Water

Covello¹,

Abbà²,

Bonaventura³

et al. 2016

Proceedings of the VII European Congress on Computational Methods in Applied Sciences and Engineering (ECCOMAS Congress 2016)

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Abstract. The first aim of this work is to improve the models currently available for the simulation of ice production in turbulent seawater, by means of the development of a multiphase model able to describe all the stages of ice production, overcoming the limitation of previous attempts, mainly based on Boussinesq approximation. We consider the mixture of ice and seawater as a dense compressible fluid, and we model the behaviour of seawater by an equation of state that links seawater density to temperature, salinity and pressure. The model is able to reproduce the interaction phenomena occurring between phases when the ice volume fraction exceeds the values allowed by the Boussinesq approximation, including in the momentum equations additional terms, related to the drag force between liquid and particles, and to the particle-particle interaction force. The second aim of our work is to implement and validate a numerical solver of our model. For this purpose, the model uses a sophisticated modelling approach, typically adopted for the numerical simulation of multiphase flows of industrial interest. The multiphase model can be coupled to the Large Eddy Simulation technique. The behaviour of the governing equations in the incompressible limit is investigated by means of a low-Mach number asymptotic analysis. The divergence constraint condition for the velocity field of continuous phase can then been imposed on the zero-Mach number equations by means of a projection method. The governing equations are discretized using the finite volume method, and the performance of the multiphase model has been assessed by solving a laminar Rayleigh-Bénard convection, for both large and small ice concentration regimes. In small concentration regime, the numerical solutions have been compared with the solutions obtained by a finite difference numerical code, based on the Boussinesq approximation.

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Frazil dynamics and precipitation in a water column with depth-dependent supercooling

Cited by 55 publications

References 33 publications

Frazil-ice growth rate and dynamics in mixed layers and sub-ice-shelf plumes

Frazil-ice growth rate and dynamics in mixed layers and sub-ice-shelf plumes

The opening of wind-driven polynyas

A Multiphase Model for the Numerical Simulation of Ice-Formation in Sea-Water

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