Ice Processes Research Articles

Influence mechanism of AC electric field on rime ice accretion on the insulator and its experimental verification in the natural environment

Insulator icing can easily trigger flashover trips in heavily ice-covered areas, and analyzing the formation mechanism of ice accumulation on the insulator is essential for predicting its flashover development. To accurately dissect the process of insulator icing, a coupled mathematical model of the flow field and electric field, as well as a droplet motion model were elaborated in this paper based on the principles of fluid mechanics and electromagnetic field. Subsequently, the characteristics of droplet motion deviation and its physical collision process with an insulator surface under AC electric field were investigated. The results demonstrate that the charged droplets tend to oscillate along the electric field lines in AC electric field, and the amplitude of the oscillation increases with the applied voltage increasing. Moreover, the number of droplets captured by the insulator rises with the increase of voltage, wind speed, and median volume diameter of the droplet. Combined with the simulation and natural icing experiments, it is observed that ice branches grow in the direction of electric field force, and as the voltage rises, ice branches gradually spread from the edge of the shed to its surface, increasing surface roughness. The density of ice exhibits an inverted U-shaped relationship as the electric field strength increases. Ice mass and ice length present nonlinear growth with an increase in icing time. Furthermore, compared with that without energization, the icing amount and icing length increase by more than 13 % under AC voltage of 40 kV.

Numerical study of ice impacted by a vehicle launched underwater based on Smoothed Particle Hydrodynamics

ABSTRACT In this paper, a new method coupling the traditional Smooth Particle Hydrodynamics (SPH) with the Weakly-Compressible Smoothed Particle Hydrodynamics (WCSPH) was proposed to simulate the process of ice impacted by a vehicle launched water. The ice resistance and the motion characteristics of the vehicle were studied under different ice thicknesses, the radial dimension of the ice, the speeds of the vehicle, and the aspect ratios of the vehicle. The influence of ice thickness on the ice resistance is more reflected in the time of action rather than the peak value. When the vehicle is moving at a high speed, the effect of ice thickness on the velocity loss rate decreases, and the curves of acceleration show high similarity. When the velocity of the vehicle is greater than 50m/s, the effect of the radial size of the ice layer is negligible, and the peak value of acceleration is around 6km/s².

Numerical Simulation of Ice Crystal Accretion and Aerodynamic Impacts on Wind Turbine Blades in Cold Climates

With the advancement of science and technology, wind power generation has been widely adopted globally. However, ice accretion severely limits the operational efficiency and structural safety of wind turbines in cold regions, while existing research primarily focuses on the impact of supercooled droplets on blade icing, the influence of ice crystals in cold environments on the blade icing process has been largely overlooked. This study systematically simulated the accretion of ice crystals and supercooled droplets under clear ice conditions. It evaluated the effects of various ice crystal parameters on the icing process using Fensap-Ice, which is an advanced icing simulation tool. The results indicate that ice accretion, driven by the combined action of ice crystals and supercooled droplets, weakened ice corners, making the ice shape smoother and fuller. When the angle of attack of the ice-covered airfoil exceeded 15°, a separating vortex formed on the suction side of the blade, leading to a reduction in the lift coefficient. The findings of this study highlight the critical role of ice crystals in the icing process and provide a scientific foundation for understanding the icing mechanism under complex meteorological conditions.

River Ice Effects on Sediment Transport and Channel Morphology—Progress and Research Needs

Sediment transport in alluvial channels has a long history of intensive research. River ice could affect sediment transport and channel morphology through the impact of various dynamic and thermal ice processes. However, studies on sediment transport under the influence of ice have been minimal until recent years. This phenomenon was partially due to the complicated interactions between ice, flow, and sediment dynamics, which require a good understanding of the river ice process, in addition to the difficult field data collection conditions. This paper reviews the progress and needs of river ice-related research on sediment transport and channel morphology, including the influence of ice cover and surface ice runs on sediment transport, the effects of frazil ice, anchor ice, and bank stability with freeze-thaw effects.

Increased vulnerability of Arctic potential ice roads under climate change

Temporary ice roads built by the process of snow compaction, watering, and icing during cold winters are lifelines for land access in remote Arctic. In the context of the Arctic amplified warming, the vulnerability of potential ice roads under the influence of complex climate system remains unclear. Here, we construct a potential ice road assessment model that allows quantization of the climatic suitability of potential ice roads in the Arctic. Using satellite remote sensing and meteorological data, we find changes in surface air temperature and snow cover reduced the climatic suitability of potential ice roads during 1979–2017. Spatially, potential ice roads in North America face more immediate threats due to decreased snow depth compared to Eurasia. Before the end of the 21st century, we project a further decline in the climatic suitability of potential ice roads, primarily due to increasing surface air temperatures and decreasing permafrost stability. Taking precious metal/diamond exploration as an example, we conclude that mining activities associated with ice roads will face access difficulties by 2050–2100 due to the decreased potential ice roads. These results give new insights into the challenges and opportunities of Arctic overland travel.

Role of a key microphysical factor in mixed-phase stratocumulus clouds and their interactions with aerosols

Abstract. This study examines the ratio of ice crystal number concentration (ICNC) to cloud droplet number concentration (CDNC), that is ICNC / CDNC, in mixed-phase stratocumulus clouds. This examination is performed using a large-eddy simulation (LES) framework and is one of the efforts toward a more general understanding of mechanisms controlling cloud development and aerosol–cloud interactions, as well as the impacts of ice processes on them in mixed-phase stratocumulus clouds. For the examination, this study compares a case of polar mixed-phase stratocumulus clouds to one of midlatitude mixed-phase stratocumulus clouds with weak precipitation. It is found that ICNC / CDNC plays a critical role in causing differences in cloud development with respect to the relative proportion of liquid and ice mass between the cases by affecting in-cloud latent-heat processes. Note that this proportion has an important implication for cloud radiative properties and, thus, for climate. It is also found that ICNC / CDNC plays a critical role in causing differences in the interactions between clouds and aerosols and in the impacts of ice processes on clouds and their interactions with aerosols between the cases by affecting in-cloud latent-heat processes. Findings of this study suggest that ICNC / CDNC can be a simplified general factor that contributes to a more general understanding and parameterization of mixed-phase clouds, their interactions with aerosols and the roles of ice processes within them.

Dynamics simulation analysis of the melting process of ice on the surface of aramid IIIA fabrics

In many industries, workers are facing the inconvenience caused by icing on fabrics. Fabric is a porous material, and researchers generally hold that porous material is not suitable for being used as an anti-icing material. Therefore, research on the anti-icing properties of fabrics have not attracted researchers' attention, thus relevant research results are few. The influence of sample surface wettability on snow melting has been rarely studied in depth. In this paper, a test device for testing the melting rate of ice on the surface of a sample was developed. Based on this experiment, a simulation model for simulating the melting process of the ice on the aramid IIIA fabric samples was established based on the melting promoting anti-icing theory. This work also indicates that the use of computational models in the study of ice melting processes is successful. Results show that the relative error between the simulated value and the experimental value was 1.63%. These computational models provide details on the phase transition and temperature changes of ice during the melting process, which are difficult to observe in experiments. Meanwhile, the simulated phase transition of ice is consistent with actual observations. The results indicate that the simulation model established in this article can be extended to study the melting process of ice on aramid IIIA fabric samples, and can be used to guide the study of the anti-icing performance of aramid IIIA fabrics.

Deposition of Water Vapor on Au(001) Substrates: Effect of Temperature and Deposition Frequency.

Ice formation from water vapor is a common phenomenon with significant implications for both natural ice formation and industrial processes. However, there remains controversy over how deposition frequency and substrate temperature affect the structural forms of deposition products and their formation processes. In this study, we employed molecular dynamics simulations to investigate the deposition process of water vapor onto a cold Au(001) substrate at different temperatures and deposition frequencies. We analyzed the effects of temperature and deposition frequency on the forms of deposition products including bilayer hexagonal ice, amorphous water, and their mixtures. Additionally, we identified and explained the unique formation of square ice as an unstable intermediate within specific temperature and deposition frequency ranges. We also discuss the crystallization processes of pancake- and droplet-like amorphous waters. This research contributes to a better understanding of ice formation, with implications for more accurate forecasting of natural ice formation and improved control of artificial ice processes.

UV processing of icy pebbles in the outer parts of VSI-turbulent disks

Icy dust particles emerge in star-forming clouds and are subsequently incorporated in protoplanetary disks, where they coagulate into larger pebbles up to millimeter in size. In the disk midplane, ices are shielded from UV radiation, but moderate levels of disk turbulence can lift small particles to the disk surface, where they can be altered, or destroyed. Nevertheless, studies of comets and meteorites generally find that ices at least partly retain their interstellar medium (ISM) composition before being accreted onto these minor bodies. We modeled this process through hydrodynamical simulations with vertical shear instability (VSI) driven turbulence in the outer protoplanetary disk. We used the PLUTO code in a 2.5 D global accretion setup and included Lagrangian dust particles of 0.1 and 1 mm sizes. In a post-processing step, we used the RADMC3D code to generate the local UV radiation field to assess the level of ice processing of pebbles. We find that a small fraction (∼17%) of 100 µm size particles are frequently lifted up to Z/R = 0.2, which can result in the loss of their pristine composition as their residence time in this layer allow effective CO and water photodissociation. The larger 1 mm size particles remain UV-shielded in the disk midplane throughout the dynamical evolution of the disk. Our results indicate that the assembly of icy bodies via the accretion of drifting millimeter-sized icy pebbles can explain the presence of pristine ice from the ISM, even in VSI-turbulent disks. Nevertheless, particles ≤100 µm experience efficient UV processing and may mix with unaltered icy pebbles, resulting in a less ISM-like composition in the midplane.

How Ice Mapping Can Help Manage and Prevent Ice Jams: Remote Sensing Monitoring of the Saint-François River, Québec

We focus on the Saint-François River (Quebec), which is known for recurrent ice jam-induced floods. This study addresses monitoring deficiencies and proposes solutions by presenting a comprehensive large-scale ice cover monitoring approach using diverse remote sensing tools for managing ice-jam risks effectively on this watercourse. We achieved three sub-objectives: (1) gathering spatial characteristics of the ice jam by acquiring images during the ice jam with an RGB camera-equipped drone; (2) mapping river ice using radar and optical images; and (3) river segmentation based on the dominant ice process. The methodological approach integrates data remotely sensed before and during the ice jam event, employing various tools. By comparing remote sensing methods with traditional monitoring, we underscore the importance of spatial data acquisition in ice-jam risk management. Orthomosaic and summary maps illustrate ice evolution processes, highlighting remote sensing efficacy in discerning hydro-meteorological events and emphasizing the need to target specific areas for risk mitigation. River segmentation based on the dominant ice process provides insights into freeze and thaw sequences, thereby illustrating ice evolution processes.

Influence of Ice Growth Mode on the Ice Thickness and Shape Prediction of Two-Dimensional Airfoil

Computational results of aircraft icing and predictions of ice shape are not only determined by the solutions of air-supercooled droplet two-phase flow and icing thermodynamic models of surface water film, but are also influenced by the growth mode of the ice layer. Two ice growth modes were established in a two-dimensional (2D) icing process simulation framework to calculate the ice thickness and ice shape, depending on whether surface deformation of the icing process was considered. Ice accretion simulations were performed with the two ice growth modes for an NACA0012 airfoil under rime ice and mixed ice conditions, and the results of ice amount, ice thickness, and ice shape were compared and analyzed. Under the same amount of ice formation, the ice thickness and ice shape obtained using different ice growth modes vary. The ice thickness and the ice shape size are relatively large without considering surface deformation, whereas the results with growth correction show a certain degree of reduction, which is more noticeable around the leading edge and the ice horns. However, the degrees of difference in ice thickness and ice shape are not the same, and the deviation in ice thickness is more obvious. Furthermore, the ice thickness and ice shape obtained using the ice growth correction mode are more consistent with experimental data and commercial software results, verifying the accuracy of the ice simulation method and the necessity of considering ice surface deformation. This paper is an essential guide for understanding the icing mechanism and accurately predicting two-dimensional ice shape.

The Role of Sea Ice Insulation Effects on the Probability of AMOC Transitions

Abstract Recent simulations performed with the Community Earth System Model (CESM) have suggested a crucial role of sea ice processes in Atlantic meridional overturning circulation (AMOC) hysteresis behavior under varying surface freshwater forcing. Here, we further investigate this issue using additional CESM simulations and a novel conceptual ocean–sea ice box model. The CESM simulations suggest that the presence of sea ice gives rise to the existence of statistical equilibria with a weak AMOC strength. This is confirmed in the conceptual model, which captures similar AMOC hysteresis behavior as in the CESM simulation and where steady states are computed versus freshwater forcing parameters. In the conceptual model, transition probabilities between the different equilibrium states are determined using rare event techniques. The transition probabilities from a strong AMOC state to a weak AMOC state increase when considering sea ice insulation effects and indicate that sea ice promotes these transitions. On the other hand, sea ice insulation effects strongly reduce the probabilities of the reverse transition from a weak AMOC state to a strong AMOC state and this implies that sea ice also limits AMOC recovery. The results here indicate that sea ice effects play a dominant role in AMOC hysteresis width and influence transition probabilities between the different equilibrium states. Significance Statement We develop a novel conceptual ocean–sea ice box model to explain AMOC hysteresis behavior recently found in a modern complex climate model (the Community Earth System Model) and determine how sea ice insulation effects influence the hysteresis width and the probability of AMOC transitions.

Numerical analysis of glaze ice accretion on cables by considering the effects of typical in-plane vibrations

During the glaze icing process, cables experience vibrations due to the presence of aerodynamic forces, gravity, and other external forces. In most existing glaze icing models, the cables are assumed to be fixed, and water film is just run-down streams that do not reflect the complexity of the ice accretion process. To reveal the effects of in-plane motions of cable on the glaze icing process, two typical in-plane motions of aeolian vibration and galloping are taken into consideration and a mathematical water film-ice layer model is proposed for the first time. Based on the water film-ice layer model, ice accretion and water flow on the vibrating cables are studied, and key parameters of Collision Efficiency (CE), aerodynamic coefficients, and water film are evaluated by comparison with fixed cables. Moreover, by iterating the discretized mass and energy conservation equations with the computed aerodynamic coefficients, the effects of in-plane motions of the cable on water film and ice shapes are computed. The model then is verified with published experimental and numerical data. The results show that in-plane motions of the cables enlarge the windward face in dynamic forms which have certain effects on water film and ice shapes, and the model could provide accurate predictions of ice accretion.

Stereooptical Methods of Sea Surface Processes Registration

This work presents the optical methods for measurements of physical parameters on sea surface also covered by ice by using stereo cameras. New method of images with sea ice processing is offered. It can detect areas of open water and sharp edges on ice, which influence on radar signal refraction. This method is based on area of interest detection on optical images, statistical parameters for each area calculation, classification and local level definition to recognize needed structures. By using stereo system perspective distortions can be corrected and physical parameters of wind waves and sea ice can be calculated. This method was probe on stereo images obtained from 90th voyage of R/V «Akademik Mstislav Keldysh» in the Laptev Sea.The results of ripple waves velocity measurements in case on open water by using development previously stereo method is presented. Comparison with Doppler shift of microwave signal is made.The methods presented in this paper are of interest in field experiments simultaneously with the use of coherent radar stations for the quantitative interpretation of radar data, as well as for remote monitoring of the sea surface and ice conditions methods development.

Redox Chemical Transformation of Organic and Inorganic Compounds in Frozen State - Intrinsic Electron Transfer Processes in Ice

Ice is one of the most abundant substances on Earth. However, little research has been done on ice as a medium for chemical reactions. Most of chemical reactions take place slowly when temperature drops based on Arrhenius Equation (k=A·e-EA/RT). However, it has been found that several chemical processes markedly accelerated in ice phase. For example, Takenaka et. al. reported that the NO2 - oxidation to NO3 - in the presence of O2 which is very slow reaction in aqueous solution was markedly accelerated (appx. 105 times) by freezing. The enhanced chemical transformation is attributed to the Freeze Concentration Effect, whereby organic and inorganic compounds are separated from ice crystals and highly concentrated in unfrozen parts or ice grain boundaries.In this presentation, we want to introduce accelerated chemical redox reactions in frozen state such as 1)enhanced redox dissolution of metal oxide/clay minerals in ice and the novel process for the new mineral formation 2)accelerated chemical transformation of iodine species in frozen state, and 3) accelerated redox transformation of organic and inorganic pollutants in ice such as Cr(VI)/organic reductants, Cr(VI)/As(III), Cr(VI)/H2O2, Cr(VI)/NO2 - and Cr(VI)/phenolic pollutants systems. The detailed research background, experimental conditions, mechanistic explanation, and effects on climate changes will be discussed in the presentation.

Tropical cyclone activity over western North Pacific favors Arctic sea ice increase.

Teleconnections between the tropics and the Arctic have attracted a lot of scientific interest. However, the mechanisms by which tropical synoptic-scale systems influence the variability of Arctic sea ice remain unknown. In this study, we highlight the impacts of tropical cyclone (TC) activity over the western North Pacific (WNP) on Arctic Sea Ice Concentration (SIC) using observational evidence and climate model simulation experiments. Our findings demonstrate significant positive correlations between Accumulated Cyclone Energy (ACE) in the WNP and SIC in the Arctic-Pacific Sector (APS), particularly when considering a 30-day lag. The TC activity over the WNP induces Rossby wave train propagation towards the Arctic, leading to anomalous cyclonic circulation over the upper troposphere of the APS. The anomalous cyclone over the Arctic, on one hand, signifies the deepening of the Arctic polar vortex and diminishes adiabatic warming over the APS, subsequently inducing cooling and drying of the lower Arctic air. This process reduces downward longwave radiation, promoting an increase in September APS SIC. On the other hand, the anomalous cyclone over the Arctic hinders the export of sea ice and local melting processes throughout the Fram Strait. These findings contribute to a deeper comprehension of tropics-Arctic teleconnections.

Multifunctional laser-ablated lubricant-infused slippery film with self-sensing and anti-icing/deicing properties

In this paper, we have developed a multifunctional laser-ablated lubricant-infused slippery film (MLLSF) by combining laser-induced graphene and lubricant-infused processes. Due to its lubricant-infused slippery surface characteristics, the MLLSF can decrease the ice adhesion strength to 7 kPa and prolong the ice time to 5 min at -20 °C. At the same time, benefitting from the outstanding photothermal effect of the laser-induced graphene conductive network, the surface temperature can rapidly rise from -20 °C to 45.6 °C in 60 s under 808-NIL illumination, thereby effectively melting the ice. More importantly, owing to the temperature sensing ability of the LIG conductive network, the prepared MLLSF can monitor the whole process of droplet icing and deicing process in real time. Therefore, this MLLSF with self-sensing, anti-icing and deicing properties has important practical values in monitoring and removing ice.

A model of freeze desalination for predicting salt concentration in ice using the laws of conservation of matter & mass

The assessment of freeze desalination (FD) efficiency is lagging behind due to the lack of an effective means of determining ice total dissolved solid (TDS). In this paper, an ice TDS prediction model was constructed by utilizing the law of conservation of matter (LCMat) and conservation of mass (LCMas) in the icing process. It was concluded that the average TDS ice crystals in any icing process was correlated with the TDS of the raw (concentrated) water at the starting of freezing, the salt mass change rate of the concentrate water, and the volume of ice crystals. A one-way FD test was carried out using the saltwater from South Xinjiang, and the exponential equation model and linear equation model of LCMat-LCMas were derived, and the simulation accuracy of LCMat-LCMas was verified by using the test data. The results show that the model has high prediction accuracy. The exponential equation model is suitable for predicting the ice TDS for ice with thickness within 15 cm, and the linear equation is suitable for predicting the ice crystal TDS for ice thicker than 15 cm. Further validation of the model accuracy is needed for larger cooled areas and icing thicknesses, and multidirectional icing processes.

The effect of dilution on the energy dissipation in water interstellar ice analogues

Context. Interstellar ices and their energetic processing play an important role in advancing the chemical complexity in space. Interstellar ices covering dust grains are intrinsically mixed, and it is assumed that physicochemical changes induced by energetic processing – triggered by photons, electrons, and ions – strongly depend on the content of the ice. Yet, the modelling of these complex mixed systems in experiments and theory is complicated. Aims. In this paper, we investigate the effect of infrared irradiation on a series of different molecules mixed with porous amorphous solid water (pASW) to study the release of vibrational energy in the hydrogen-bonding network of water as a function of mixing ratio and ice content. Particularly, we select mixtures of 20:1 H2O:X and 5:1 H2O:X with X=CO2, NH3, or CH4. Methods. Infrared radiation was supplied by the intense and tunable free electron laser (FEL) 2 at the HFML-FELIX facility. We monitored the structural changes in the interstellar ice analogue after resonant infrared excitation using Fourier-transform reflection absorption infrared (FT-RAIR) spectroscopy. Results. We observed that on-resonance irradiation at the OH-stretching vibration of pASW results in quantitatively identical changes compared to pure pASW for all investigated mixtures. The structural changes we observed closely resemble the previously reported local reordering. The 5:1 mixtures show weaker changes compared to pure pASW, with a decrease in strength from NH3 to CO2. Conclusions. Since the hydrogen-bonding network of pASW restructures similarly upon FEL irradiation, regardless of the mixing component, treating ice layers in models that simulate energy dissipation in the hydrogen-bonding network as pure H2O ice layers can be a justified approximation. Hence, complex systems might not always be necessary to describe the infrared energetic processing of ices.

1-Adamantanamine implementation in surface engineering of biomimetic PVDF-based membranes for enhanced membrane distillation

Membrane distillation (MD) stands at the forefront of desalination technology, harnessing the power of phase change to separate water vapor from saline using minimal energy resources efficiently. In response to this challenge, membranes with tuned pores morphology and surface chemistry with biomimetic 3D pine-like structures with improved affinity to water (desalination) and/or hazardous VOC (VOC removal) were developed and studied systematically. By implementing VIPS-PVDF membranes and a green modifier of 1-adamantanamine for the first time, membranes with a revolutionary network architecture were generated. The modifier was introduced either physically to the polymeric matrix or chemically through covalent attachment onto the surface and inside the porous structure. As a result, membranes that defy wetting under extreme hydrostatic pressures (>11.5 bar) were produced while preserving unparalleled vapor transport efficiency. The 1-adamantanamine promotes transport and enhances the affinity to the VOC, ensuring excellent membrane performance at different applications of the MD process. Transport was enhanced >3.6 times and separation factor beta changed from 3.48 to 15.22 for MTBE removal and from 2.0 to 3.46 for EtOH removal when comparing pristine PVDF with membrane chemically modified with 1-adamantanamine (PVDF_Ch02). The process separation index during the MTBE removal changed from 20 kg m−2 h−1 (PVDF) to 297 kg m−2 h−1 (PVDF_Ch02). All materials were highly stable and durable during the MD applications. This innovative approach not only revolutionizes desalination but also holds immense promise for diverse applications beyond, particularly in the realm of wastewater treatment. A study of the icing process on a cold plate with new membranes provided deeper insight into the icing mechanism and the role of membrane LEP in it.