Artificial Ice Research Articles

Notes on Towed Self-Propulsion Experiments with Simulated Managed Ice in Traditional Towing Tanks

Efficiency estimation of a propeller behind a vessel’s hull while sailing through ice floes, together with the ship’s resistance to motion, is a key factor in designing the power plant and determining the safety measures of a ship. This paper encloses the results from the experiments conducted at the CEHINAV towing tank, which consisted of analyzing the influence of the concentration at the free surface of artificial blocks, simulating ice, in propeller–block interactions. Thrust and torque were measured for a towed self-propelled ship model through simulated broken ice blocks made of paraffin wax. Three block concentrations of different block sizes and three model speeds were studied during the experimentation. Open-water self-propulsion tests and artificial broken ice towed self-propulsion tests are shown and compared in this work. The most relevant observations are outlined at the end of this paper, as well as some guidelines for conducting artificial ice-towed self-propulsion tests in traditional towing tanks.

An elastoplastic damage ice material model based on modified Tsai-Wu yield criterion: Experiment, theory and numerical application

Ice, as a novel green and sustainable building material, has attracted more and more attention in building engineering. Appropriate ice material models are crucial for the performance analysis of the increasing ice structures. There is still challenging in modelling ice responses due to the complexity of ice. This study aims to present a nonlinear elastoplastic damage model for ice material. First, a triaxial compression test of artificial ice is conducted. Based on the test results, the modified Tsai-Wu failure criterion with better performance in the tensile zone and physical meaning for hydraulic strength is established. Then, combining plasticity theory with damage mechanics, an elastoplastic damage constitutive law considering the difference between tensile and compressive properties is proposed. The piecewise damage model and the Weibull exponential damage model are employed for compression and tension damage, respectively. Moreover, the numerical iterative algorithm is developed and a user-defined material subroutine (UMAT) is embedded in the finite element software ABAQUS to simulate the mechanical properties of ice. Furthermore, the constitutive model is verified by comparing the FEM results with the results of uniaxial compression, triaxial compression, and three-point bending tests. The results show that the constitutive model can well describe the stress-strain nonlinear behavior and capture the basic failure mode of ice materials. Finally, considering temperature affecting on the failure surface, a temperature dependent ice material model is developed. The current study would help in the design, operation and maintenance of ice structures.

Investigation of the temperature field of the ice sheet in a prefabricated curling ice rink: Experiment and finite element simulation

Ice temperature is crucial for the quality of artificial ice rinks and ice sports. This study aims to investigate the temperature field of the ice sheet in the prefabricated curling rink for the Beijing Winter Olympics through a combination of experiments and simulations. Through the analysis of heat exchange in the ice sheet, three numerical models of the temperature field of the ice sheet were developed using the finite element software ABAQUS. An environmental temperature model and a comprehensive ambient temperature were proposed to consider thermal radiation and heat convection. Moreover, the simulation results at varying positions were validated through on-site observations of ice temperature, the comparison of three temperature field modeling methods was conducted, and the distribution characteristics of the temperature field were analyzed. In addition, the impact of various parameters on the ice temperature was investigated, and a parameter of the response efficiency of the ice temperature was proposed to conduct sensitivity analysis. Results show that the simplified finite element model of the ice sheet could provide a practical approach to obtain the ice temperature fields. The horizontal and vertical distribution characteristics of the ice temperature can be mathematically described using a sine function with variable amplitude and a cubic polynomial, respectively. A sensitivity analysis indicates that the response efficiency of the ice surface temperature corresponding to cooling medium, ceiling, and air is 90%, 10%, and 10%, respectively. And the ice surface is effectively regulated by the temperature of the cooling medium. The current study would help in the design, operation, and maintenance of ice sheets.

Ultrastrong magnon-magnon coupling and chiral spin-texture control in a dipolar 3D multilayered artificial spin-vortex ice

Strongly-interacting nanomagnetic arrays are ideal systems for exploring reconfigurable magnonics. They provide huge microstate spaces and integrated solutions for storage and neuromorphic computing alongside GHz functionality. These systems may be broadly assessed by their range of reliably accessible states and the strength of magnon coupling phenomena and nonlinearities. Increasingly, nanomagnetic systems are expanding into three-dimensional architectures. This has enhanced the range of available magnetic microstates and functional behaviours, but engineering control over 3D states and dynamics remains challenging. Here, we introduce a 3D magnonic metamaterial composed from multilayered artificial spin ice nanoarrays. Comprising two magnetic layers separated by a non-magnetic spacer, each nanoisland may assume four macrospin or vortex states per magnetic layer. This creates a system with a rich 16N microstate space and intense static and dynamic dipolar magnetic coupling. The system exhibits a broad range of emergent phenomena driven by the strong inter-layer dipolar interaction, including ultrastrong magnon-magnon coupling with normalised coupling rates of Δfν=0.57\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\frac{\\Delta f}{\ u }=0.57$$\\end{document}, GHz mode shifts in zero applied field and chirality-control of magnetic vortex microstates with corresponding magnonic spectra.

A thermodynamic analysis of alternative cooling options for beverages

The so-called artificial ices are easily found on the market nowadays. They are commercialized with the promise of freezing drinks in general. The advantage over traditional ice is that they do not dilute drinks during the cooling process. These artificial ices come in a variety of forms, including plastic, gel, stone, and metal. In this study, we investigate theoretically and experimentally the effectiveness of these objects in comparison to traditional water ice (ordinary ice). Our findings suggest that artificial ice produced without water provides a less significant cooling effect when compared to those made with water and traditional water ice. Additionally, we observed that the material used to coat the ice has a significant impact on the cooling process and can be selected based on its specific application. We also suggest an experimental parameter that can be used to verify the effectiveness of these objects. Finally, our results are supported by thermodynamic laws.

Rational design patterns for artificial ice cluster construction at bottoms of mined-out kimberlite pits by means of layer-by-layer water filling

Rational design patterns for artificial ice cluster construction at bottoms of mined-out kimberlite pits by means of layer-by-layer water filling

Design Analysis of CO2 Refrigeration System for Artificial Ice Rinks

With the increasingly serious environmental problems, the use of natural refrigerants has become an inevitable trend. In this paper, an artificial ice rink with a CO2 refrigeration system is studied, and the ice rink site and refrigeration system process are analyzed. The structure of the ice rink site includes a surface layer, a base layer, and an antifreeze layer. The refrigeration system flow has indirect ice rink refrigeration systems and direct ice rink refrigeration systems. With the application of the CO2 transcritical refrigeration cycle, the efficiency of the ice rink has been greatly improved.

Modeling of Non-stationary Heat Transfer of Floor Structures of Rooms with Artificial Ice

Statement of the problem. The purpose of the scientific article is to develop an adjusted methodology and program for calculating the non-stationary heat exchange of floor structures with artificial ice, taking into account the asymmetric radiation cooling of heat exchange surfaces to determine the time they reach the critical temperature. Results. An important characteristic of the adjusted technique is the use of the average coefficient of irradiation of the surfaces of the structure, as well as taking into account the displacement of the thermal center during its asymmetric heating. The technique takes into account the radiant component from the ice surface in the determining generalized heat transfer coefficient. Conclusions. The considered features make it possible to increase the accuracy of calculating the cooling time of the surface of the structure to critical values, which can be used to adjust the operating modes of microclimatic systems of rooms with artificial ice.

Numerical Study on Wave–Ice Floe Interaction in Regular Waves

The marginal ice zone (MIZ) is located at the junction of ice-covered areas and open water, where waves cause ice floes to break up and change their state of motion, thus threatening the safety of ships navigating the ice. This study employs the Structured Arbitrary Lagrangian–Eulerian (S-ALE) method and the numerical wave-making method based on dynamic boundary conditions to numerically examine the motion response of ice floes in waves. The longitudinal motion of ice floes in waves can be classified into two distinct states, namely irregular and regular, depending on the wavelength. In the short-wave range, the ice floes exhibit primarily irregular motion, whereas in the long-wave range, their motion becomes regular, resembling that of isolated ice floes. The longitudinal motion response of the ice floes remains unaffected by their size. However, the longitudinal velocity, surge velocity, and displacement of the ice floes are influenced by the wavelength. Furthermore, the numerical calculations are compared to the model test conducted in a towing tank using paraffin artificial ices, revealing a qualitative agreement between the experimental and numerical results.

Penetration of a solid spherical particle into artificial and natural wet granular ice layers: Dynamic strength characterization

The strength of wet granular ice layers is an important quantity for modelling the behaviour of ice accretions encountered in aircraft engine icing since it determines the dynamics of the collision of ice crystals, their penetration into the layer, breakup and the characteristics of the ejected material. In the present study, impact tests of 3.18 mm nylon spheres are conducted on wet granular ice layers for a dynamic strength characterization. An experimental setup and methodology are designed to measure the crater depth for impact velocities ranging from 5 ms−1 to 90 ms−1. Experiments are conducted using both ice layers generated by ice crystal accretion on a solid substrate inside an icing wind tunnel and artificial ice layers prepared in a laboratory environment. By fitting the Poncelet penetration equation to the experimental data, two dimensionless parameters are derived that characterize the strength of the investigated ice layers in relation to the layer inertial resistance and apparent yield strength. A key finding is that strong connections between individual ice particles exist for ice layer generated in the wind tunnel, originating from re-freezing of liquid water near the particle contacts. Only by re-enforcing the ice particle connections in ice layers prepared in the laboratory, comparable strength values are obtained. The presented methodology enables measurement of ice layer strength and comparison at different facilities as well as conducting advanced experiments with realistic ice layers in a laboratory environment.

Experimental and numerical study of zonal heat and moisture migration inside artificial ice rinks

Ice rinks feature typical non-uniform indoor environment with evident vertical and horizontal parameter differences. A validated CFD model established based on the on-site measurement is utilized to investigate the indoor environment along with the zonal heat and moisture transfer characteristics in a recreational ice rink. It is demonstrated that there are both cooling and heating demands inside the ice hall due to different control standards for various functional regions. Zonal mixing induces a large amount of additional load with 53.5% of the heat brought by the dehumidifiers eventually flowing into the ice sheet and carried away by the refrigeration system. The ice sheet cooperates with the dehumidifiers to dislodge the indoor moisture gain. The importance of proper design of ventilation systems and adequate physical separation is emphasized. Zonal migration coefficients are proposed, and the variation range influenced by different factors are investigated. The migration coefficients between the near-ice zone and the occupied ice field are around 4 W/(m2·K) and 5 g/(s·m2), and those between the occupied and unoccupied ice field are around 14 W/(m2·K) and 18 g/(s·m2). The findings provide a simplified calculation method for regional heat and moisture flow, and are beneficial for the optimization of system design and energy conservation in ice rinks.

Ice rule breakdown and frustrated antiferrotoroidicity in an artificial colloidal Cairo ice

We combine experiments and numerical simulations to investigate the low energy states and the emergence of topological defects in an artificial colloidal ice in the Cairo geometry. This type of geometry is characterized by a mixed coordination (z), with coexistence of both z = 3 and z = 4 vertices. We realize this particle ice by confining field tunable paramagnetic colloidal particles within a lattice of topographic double wells at a one to one filling using optical tweezers. By raising the interaction strength via an applied magnetic field, we find that the ice rule breaks down, and positive monopoles with charge accumulate in the z = 4 vertices and are screened by negative ones () in the z = 3. The resulting, strongly coupled state remains disordered. Further, via analysis of the mean chirality associated to each pentagonal plaquette, we find that the disordered ensemble for this geometry is massively degenerate and it corresponds to a frustrated antiferrotoroid.

New six degree of freedom model for ice throw simulations

Icing and thus ice throw from wind turbines is currently unavoidable in cold climates. Therefore, the associated risk requires adequate quantification and assessment. In this study, a new six degree of freedom model with increased accuracy is introduced, which aims to overcome limitations of currently used approaches. This is achieved by taking into account translation and rotation of the thrown fragments and thus allowing to represent more complex trajectories. To limit the necessary numerical effort, look-up tables for forces and moments are pre-calculated with the help of CFD simulations. Validation of the model was achieved by comparison to real life experiments. For these, artificial ice fragments based on collected real fragments were produced and released from wind turbines under partially controlled conditions. This showed a significantly improved agreement between simulated and observed values when compared to the state-of-the-art model. Since the distribution patterns of the presented model differ significantly from those of the established model, these consequences must be taken into account in future risk assessments.

Artificial Magnetic Tripod Ice.

We study the collective behavior of interacting arrays of nanomagnetic tripods. These objects have six discrete moment states, in contrast to the usual two states of an Ising-like moment. Our experimental data demonstrate that triangular lattice arrays form a "tripod ice" that exhibits charge ordering among the effective vertex magnetic charges, in direct analogy to artificial kagome spin ice. The results indicate that the interacting tripods have effective moments that act as emergent local variables, with strong connections to the well-studied Potts and clock models. In addition, the tripod moments display a tendency toward a nearest neighbor alignment in our thermalized samples that separates this system from kagome spin ice. Our results open a path toward the study of the collective behavior of nonbinary moments that is unavailable in other physical systems.

Reconciling ice dynamics and bed topography with a versatile and fast ice thickness inversion

Abstract. We present a novel thickness inversion approach that leverages satellite products and state-of-the-art ice flow models to produce distributed maps of sub-glacial topography consistent with the dynamic state of a given glacier. While the method can use any complexity of ice flow physics as represented in ice dynamical models, it is computationally cheap and does not require bed observations as input, enabling applications on both local and large scales. Using the mismatch between observed and modelled rates of surface elevation change (dh/dt) as the misfit functional, iterative point-wise updates to an initial guess of bed topography are made, while mismatches between observed and modelled velocities are used to simultaneously infer basal friction. The final product of the inversion is not only a map of ice thickness, but is also a fully spun-up glacier model that can be run forward without requiring any further model relaxation. Here we present the method and use an artificial ice cap built inside a numerical model to test it and conduct sensitivity experiments. Even under a range of perturbations, the method is stable and fast. We also apply the approach to the tidewater glacier Kronebreen on Svalbard and finally benchmark it on glaciers from the Ice Thickness Models Intercomparison eXperiment (ITMIX, Farinotti et al., 2017), where we find excellent performance. Ultimately, our method shown here represents a fast way of inferring ice thickness where the final output forms a consistent picture of model physics, input observations and bed topography.

Experimental investigation of ice sublimation process on ice surface in ice rink

Indoor artificial ice rinks often spend large amount of energy for dehumidifying the air, in order to prevent frosting and guarantee the ice quality. However, over drying in ice rinks would reverse ice sublimation which might cause loss of ice thickness and unevenness. This paper adopts experimental approaches to study the sublimation of ice in ice rinks. From the experimental result, ice sublimation velocity vary from 0.02 mm/h to 0.12 mm/h in common ice rink environment. The sublimation thickness mainly depends on ice temperature (ti), the air humtidy ratio (da) and air flow rate (va). The experimental results conducted to the relationship between sublimation rate (S) and sublimation factor (α) and the above parameters. Moreover, the empirical formula for sublimation is obtained by using the experimental conclusion, and the confidence is about 0.74. Experiment and formula could provide guidance for air humidity controlling in ice rinks. In order to prevent excessive loss of ice, Δd could be 0.7 ∼ 1.4 g/kg when the va is 1 m/s. In order to ensure uniform ice surface, this value is only 0.4 ∼ 0.7 g/kg when the air flow is relatively uniform. The calculation and analysis of sublimation and humidity threshold provide a theoretical basis for accurately controlling the ice rink environment. This would also be helpful to the design of air parameters and flow pattern on ice.

The Macro- and Microphysical Response Characteristics of the Multicell Hailstorm Hail-Suppression Operation: Case Study

Abstract This study analyzed the macro- and microphysical response characteristics of a typical multicell hailstorm after seeding on 27 April 2019 in Weining, China, using X-band dual-polarization radar (YLD1-D) data. An improved X-pol hydrometeor identification algorithm was employed for hydrometeor identification. According to the diffusion of the seeding agents, the seeded hailstorm was graded into three study regions, and the evolution of the seeded hailstorm was divided into four periods. The response characteristics of the seeded hailstorm in each region and period were compared and analyzed. The results show that 1) macroscopically, the decrease in the reflectivity and the height of strong echo mainly occurred in the seeded period, whereas the decrease in the echo top and the height of the storm was mainly in the postseeded period; the echo height variation of the unseeded hailstorm is obviously different from that of the seeded hailstorm; and 2) from the microscopic perspective, the decrease in low-density graupel and supercooled water and the increase in ice crystals and aggregates in the seeded region mainly occurred in the seeded period, which was consistent with the time required for the “benefit competition” after the silver iodide completed nucleation. When compared with the seeded region, the hydrometeors in the unseeded region had an opposite trend (or an in-phase trend with an obviously lower changing rate), which further indicated the impact of the artificial ice nuclei on microphysical processes in the seeded region. For hailstorms with a high content of supercooled droplets and graupel, the key mechanisms of hail suppression are “cloud water glaciation,” “beneficial competition,” and “early rainout.”

Understanding the role of polymers on the nucleating behavior of water in dilute supercooled solutions.

Understanding the nucleation behavior of water in dilute polymeric solutions is quintessential for the development of suitable artificial ice recrystallization inhibition (IRI) agents. Although poly(vinyl alcohol) (PVA) is found to be one of the most potent biomimetic IRI agents, the molecular understanding of the nucleation behavior of water in the presence of PVA is still lacking. Here, we use molecular dynamics to elucidate the role of concentration, degree of supercooling, degree of polymerization, and amphiphilicity of PVA and PVA-like polymers on the homogeneous nucleation of water in dilute polymeric solutions using the seeding method. Using classical nucleation theory (CNT), our simulations indicate an increase in the chemical potential difference between ice and melt that favors ice nucleation. However, it also predicts a significant increase in the ice-melt interfacial energy that impedes nucleation. The relative increase in the interfacial energy dominates the increase in the chemical potential difference, which results in a decrease in the nucleation rate of water with an increase in the solute concentration. This study contradicts the previous simulation study that suggested the promotion of homogeneous ice nucleation by PVA and supports the experimental observations of the heterogeneous origins of ice nucleation. Our results also suggest the non-classical origins of ice nucleation in polymeric solutions and the limitation of the CNT in predicting heterogeneous ice nucleation in polymeric solutions.

Does prognostic seeding along flight tracks produce the desired effects of cirrus cloud thinning?

Abstract. To date the climate intervention (CI) proposal of cirrus cloud thinning (CCT) was only assessed in general circulation models (GCMs) using a globally uniform distribution of artificial ice nucleating particles (INPs). In this study, we made the first attempt using the ECHAM–HAM (Hamburg Aerosol Module) GCM to simulate CCT using a fully prognostic cirrus seeding aerosol species. Seeding particles were assumed to be made of bismuth triiodide and were emitted into the atmosphere following aircraft emissions of black carbon (soot). This new approach drastically reduced the number concentration of seeding particles available as INPs in our cirrus ice nucleation sub-model compared to the globally uniform approach. As a result, we found that in order to achieve a significant signal we needed to reduce the assumed radius of emitted seeding particles by an order of magnitude to 0.01 µm and scale the mass emissions of seeding particles by at least a factor of 100 or 1000. This latter scaling factor led to a large net top-of-atmosphere (TOA) warming effect of 5.9 W m−2. This warming effect was a clear response to overseeding with a large concentration of seeding particles (>105 L−1 in the Northern Hemisphere) that was most evident in the tropics. Due to this undesired effect, in a second series of simulations we avoided seeding the tropics by restricting emissions to only the Northern Hemisphere (NH) during winter. We also found a small and insignificant effect, or overseeding, which for the extreme case was reduced compared to the global aircraft emission scenario (2.2 W m−2). Ice crystal radius anomalies were not what we expected, with the largest reduction in size found for the case with a mass scaling factor of 10 instead of the extreme, ×1000, scenario. We attributed this peculiar behavior to the differences in the competition between different seeding particle concentrations and background particles. Finally, we also found that seeding with such large concentrations increased the albedo effect of mixed-phase clouds in the NH due to less efficient cloud droplet consumption, consistent with previous findings from our model. Overall, however, based on this study it is recommended to pause further modeling efforts of CCT unless more observational-based evidence of aerosol–ice-cloud interactions indicates favorable conditions for producing the desired outcome of this CI proposal.

Three-dimensional fully-Lagrangian DEM-SPH modeling of river ice interaction with control structures

Ice control structures (ICSs) play a vital role in preventing ice jams and safeguarding communities by either stabilizing ice cover or relocating jams upstream. Understanding and modeling the interaction between ice floes and these structures is crucial for assessing their effectiveness and optimizing their designs. However, simulating these complex multi-physics systems poses challenges for numerical techniques. In this paper, we introduce and evaluate a fully-Lagrangian mesh-free continuum-discrete model based on the Smoothed Particles Hydrodynamics (SPH) method and Discrete Element Method (DEM) for three-dimensional (3D) simulation of ice interactions with control structures. To validate and parameterize the numerical model, we conduct two sets of experiments using real and artificial ice materials: (1) dam-break wave-ice-structure interaction and (2) ice-ICS interaction in an open channel. By comparing numerical and experimental results we demonstrate the capability and relative accuracy of our model. Our findings indicate that real ice generally exhibits faster jam evolution and ice passage through the ICS compared to artificial ice. Moreover, we identify the Froude number and ice material type as important factors influencing jam formation, evolution, and ICS effectiveness. Through sensitivity analysis of material properties, we highlight the significant impact of friction and restitution coefficients.