scholarly journals Wave-induced stress and breaking of sea ice in a coupled hydrodynamic discrete-element wave–ice model

2017 ◽  
Vol 11 (6) ◽  
pp. 2711-2725 ◽  
Author(s):  
Agnieszka Herman
Keyword(s):  
Sea Ice ◽  
Wave Attenuation ◽  
Wave Model ◽  
Discrete Element ◽  
Two Dimensions ◽  
Particle Model ◽  
Time Step ◽  
Bonded Particle Model ◽  
Induced Stress ◽  
Wave Induced

Abstract. In this paper, a coupled sea ice–wave model is developed and used to analyze wave-induced stress and breaking in sea ice for a range of wave and ice conditions. The sea ice module is a discrete-element bonded-particle model, in which ice is represented as cuboid grains floating on the water surface that can be connected to their neighbors by elastic joints. The joints may break if instantaneous stresses acting on them exceed their strength. The wave module is based on an open-source version of the Non-Hydrostatic WAVE model (NHWAVE). The two modules are coupled with proper boundary conditions for pressure and velocity, exchanged at every wave model time step. In the present version, the model operates in two dimensions (one vertical and one horizontal) and is suitable for simulating compact ice in which heave and pitch motion dominates over surge. In a series of simulations with varying sea ice properties and incoming wavelength it is shown that wave-induced stress reaches maximum values at a certain distance from the ice edge. The value of maximum stress depends on both ice properties and characteristics of incoming waves, but, crucially for ice breaking, the location at which the maximum occurs does not change with the incoming wavelength. Consequently, both regular and random (Jonswap spectrum) waves break the ice into floes with almost identical sizes. The width of the zone of broken ice depends on ice strength and wave attenuation rates in the ice.

scholarly journals Wave-induced stress and breaking of sea ice in a coupled hydrodynamic–discrete-element wave–ice model

2017 ◽  
Author(s):  
Agnieszka Herman
Keyword(s):  
Sea Ice ◽  
Wave Attenuation ◽  
Wave Model ◽  
Discrete Element ◽  
Two Dimensions ◽  
Particle Model ◽  
Time Step ◽  
Bonded Particle Model ◽  
Induced Stress ◽  
Wave Induced

Abstract. In this paper, a coupled sea ice–wave model is developed and used to analyze the variability of wave-induced stress and breaking in sea ice. The sea ice module is a discrete-element bonded-particle model, in which ice is represented as cuboid "grains" floating on the water surface that can be connected to their neighbors by elastic "joints". The joints may break if instantaneous stresses acting on them exceed their strength. The wave part is based on an open-source version of the Non-Hydrostatic WAVE model (NHWAVE). The two parts are coupled with proper boundary conditions for pressure and velocity, exchanged at every time step. In the present version, the model operates in two dimensions (one vertical and one horizontal) and is suitable for simulating compact ice in which heave and pitch motion dominates over surge. In a series of simulations with varying sea ice properties and incoming wavelength it is shown that wave-induced stress reaches maximum values at a certain distance from the ice edge. The value of maximum stress depends on both ice properties and characteristics of incoming waves, but, crucially for ice breaking, the location at which the maximum occurs does not change with the incoming wavelength. Consequently, both regular and random (Jonswap spectrum) waves break the ice into floes with almost identical sizes. The width of the zone of broken ice depends on ice strength and wave attenuation rates in the ice.

scholarly journals Toward a coupled model to investigate wave-sea ice interactions in the Arctic marginal ice zone

2019 ◽  
Author(s):  
Guillaume Boutin ◽  
Camille Lique ◽  
Fabrice Ardhuin ◽  
Clément Rousset ◽  
Claude Talandier ◽  
...  
Keyword(s):  
Sea Ice ◽  
Wave Attenuation ◽  
Coupled Model ◽  
Wave Model ◽  
The Arctic ◽  
Strong Interactions ◽  
Short Time Scale ◽  
Sea Ice Concentration ◽  
Marginal Ice Zone ◽  
Wave Induced

Abstract. The Arctic Marginal Ice Zone (MIZ), where strong interactions between sea ice, ocean and atmosphere are taking place, is expanding as the result of the on-going sea ice retreat. Yet, state-of-art models are not capturing the complexity of the varied processes occurring in the MIZ, and in particular the processes involved in the ocean-sea ice interactions. In the present study, a coupled sea ice - wave model is developed, in order to improve our understanding and model representation of those interactions. The coupling allows us to account for the wave radiative stress resulting from the wave attenuation by sea ice, and the sea ice lateral melt resulting from the wave-induced sea ice break-up. We found that, locally in the MIZ, the waves can affect the sea ice drift and melt, resulting in significant changes in sea ice concentration and thickness as well as sea surface temperature and salinity. Our results highlight the need to include the wave-sea ice processes in models aiming at forecasting sea ice conditions on short time scale, although the coupling between waves and sea ice would probably required to be investigated in a more complex system, allowing for interactions with the ocean and the atmosphere.

Research on Attenuation of Shock Induced Stress Wave in Multi-Layered Thin Cylindrical Rods

2018 ◽  
Vol 878 ◽  
pp. 35-40
Author(s):  
Fei Peng ◽  
Zhi Guang Yang ◽  
Li Peng Wang
Keyword(s):  
Stress Wave ◽  
Wave Attenuation ◽  
Impact Load ◽  
Layered Media ◽  
One Dimension ◽  
Stress Wave Propagation ◽  
Propagation Theory ◽  
Induced Stress ◽  
The One ◽  
Wave Induced

The attenuation of stress wave induced by impact load in multi-layered thin cylindrical rods has been investigated and analyzed. Firstly, based on stress wave propagation theory, the one dimension solution of the response of stress wave in three-layered media has been given. Secondly, a three-layered thin cylindrical rod has been established through FEM, and the propagation and attenuation of stress wave in it has been analyzed. The analytical and numerical results showed that the stress wave attenuation could be achieved by using multi-layered media.

Numerical Simulation of Granite on Pre-Stressed Machining by Discrete Element Method (DEM)

2013 ◽  
Vol 372 ◽  
pp. 646-649 ◽  
Author(s):  
Yong Ye ◽  
Liang Kang
Keyword(s):  
Discrete Element Method ◽  
Fracture Behavior ◽  
Discrete Element ◽  
Machining Process ◽  
Particle Model ◽  
Transgranular Fracture ◽  
Transverse Cracks ◽  
Bonded Particle Model ◽  
Radial Cracks ◽  
Element Method

The bonded particle model (BPM) of granite for pre-stressed machining is build by using the discrete element method (DEM). This model can not only descript the intergranular fracture behavior but also the transgranular fracture behavior of the granite. The processes of crack propagation under different pre-stressed machining conditions are studied by means of DEM simulation. Damages and cracks of surface/subsurface are also observed. The simulation results show that, while the magnitude of pre-stress is controlled in a certatin range, the number of radial cracks reduce as the increasing of pre-stress magnitude, contray to the transverse cracks. It could be seen that maching damage is decreased and surface quality is improved by applying the pre-stressed machining method, and the discrete element method is an effective way to simulate the machining process of granite.

scholarly journals Towards a coupled model to investigate wave–sea ice interactions in the Arctic marginal ice zone

2020 ◽  
Vol 14 (2) ◽  
pp. 709-735 ◽  
Author(s):  
Guillaume Boutin ◽  
Camille Lique ◽  
Fabrice Ardhuin ◽  
Clément Rousset ◽  
Claude Talandier ◽  
...  
Keyword(s):  
Sea Ice ◽  
Wave Attenuation ◽  
Coupled Model ◽  
Wave Model ◽  
The Arctic ◽  
Wave Radiation ◽  
Strong Interactions ◽  
Sea Ice Concentration ◽  
Ocean Surface Waves ◽  
Marginal Ice Zone

Abstract. The Arctic marginal ice zone (MIZ), where strong interactions between sea ice, ocean and atmosphere take place, is expanding as the result of ongoing sea ice retreat. Yet, state-of-the-art models exhibit significant biases in their representation of the complex ocean–sea ice interactions taking place in the MIZ. Here, we present the development of a new coupled sea ice–ocean wave model. This setup allows us to investigate some of the key processes at play in the MIZ. In particular, our coupling enables us to account for the wave radiation stress resulting from the wave attenuation by sea ice and the sea ice lateral melt resulting from the wave-induced sea ice fragmentation. We find that, locally in the MIZ, the ocean surface waves can affect the sea ice drift and melt, resulting in significant changes in sea ice concentration and thickness as well as sea surface temperature and salinity. Our results highlight the need to include wave–sea ice processes in models used to forecast sea ice conditions on short timescales. Our results also suggest that the coupling between waves and sea ice would ultimately need to be investigated in a more complex system, allowing for interactions with the ocean and the atmosphere.

scholarly journals Satellite-retrieved sea ice concentration uncertainty and its effect on modelling wave evolution in marginal ice zones

2020 ◽  
Vol 14 (6) ◽  
pp. 2029-2052 ◽  
Author(s):  
Takehiko Nose ◽  
Takuji Waseda ◽  
Tsubasa Kodaira ◽  
Jun Inoue
Keyword(s):  
Sea Ice ◽  
Wave Attenuation ◽  
Chukchi Sea ◽  
Cumulative Effect ◽  
Wave Model ◽  
Subgrid Scale ◽  
Sea Ice Concentration ◽  
Ocean Surface Waves ◽  
Modelling Uncertainty ◽  
Ice Concentration

Abstract. Ocean surface waves are known to decay when they interact with sea ice. Wave–ice models implemented in a spectral wave model, e.g. WAVEWATCH III® (WW3), derive the attenuation coefficient based on several different model ice types, i.e. how the model treats sea ice. In the marginal ice zone (MIZ) with sea ice concentration (SIC) < 1, the wave attenuation is moderated by SIC: we show that subgrid-scale processes relating to the SIC and sea ice type heterogeneity in the wave–ice models are missing and the accuracy of SIC plays an important role in the predictability. Satellite-retrieved SIC data (or a sea ice model that assimilates them) are often used to force wave–ice models, but these data are known to have uncertainty. To study the effect of SIC uncertainty ΔSIC on modelling MIZ waves during the 2018 R/V Mirai observational campaign in the refreezing Chukchi Sea, a WW3 hindcast experiment was conducted using six satellite-retrieved SIC products based on four algorithms applied to SSMIS and AMSR2 data. The results show that ΔSIC can cause considerable wave prediction discrepancies in ice cover. There is evidence that bivariate uncertainty data (model significant wave heights and SIC forcing) are correlated, although off-ice wave growth is more complicated due to the cumulative effect of ΔSIC along an MIZ fetch. The analysis revealed that the effect of ΔSIC can overwhelm the uncertainty arising from the choice of model ice types, i.e. wave–ice interaction parameterisations. Despite the missing subgrid-scale physics relating to the SIC and sea ice type heterogeneity in WW3 wave–ice models – which causes significant modelling uncertainty – this study found that the accuracy of satellite-retrieved SIC used as model forcing is the dominant error source of modelling MIZ waves in the refreezing ocean.

scholarly journals Discrete Element Analysis of High-Pressure Zones of Sea Ice on Vertical Structures

2021 ◽  
Vol 9 (3) ◽  
pp. 348
Author(s):  
Xue Long ◽  
Lu Liu ◽  
Shewen Liu ◽  
Shunying Ji
Keyword(s):  
High Pressure ◽  
Sea Ice ◽  
Failure Mode ◽  
Contact Area ◽  
Loading Rate ◽  
Discrete Element ◽  
Offshore Platforms ◽  
Marine Structures ◽  
Element Analysis ◽  
Ice Pressure

In cold regions, ice pressure poses a serious threat to the safe operation of ship hulls and fixed offshore platforms. In this study, a discrete element method (DEM) with bonded particles was adapted to simulate the generation and distribution of local ice pressures during the interaction between level ice and vertical structures. The strength and failure mode of simulated sea ice under uniaxial compression were consistent with the experimental results, which verifies the accuracy of the discrete element parameters. The crushing process of sea ice acting on the vertical structure simulated by the DEM was compared with the field test. The distribution of ice pressure on the contact surface was calculated, and it was found that the local ice pressure was much greater than the global ice pressure. The high-pressure zones in sea ice are mainly caused by its simultaneous destruction, and these zones are primarily distributed near the midline of the contact area of sea ice and the structure. The contact area and loading rate are the two main factors affecting the high-pressure zones. The maximum local and global ice pressures decrease with an increase in the contact area. The influence of the loading rate on the local ice pressure is caused by the change in the sea ice failure mode. When the loading rate is low, ductile failure of sea ice occurs, and the ice pressure increases with the increase in the loading rate. When the loading rate is high, brittle failure of sea ice occurs, and the ice pressure decreases with an increase in the loading rate. This DEM study of sea ice can reasonably predict the distribution of high-pressure zones on marine structures and provide a reference for the anti-ice performance design of marine structures.

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