Full Scale Measurement on Level Ice Resistance of Icebreaker

2011 ◽  
Author(s):  
Abdillah Suyuthi ◽  
Bernt J. Leira ◽  
Kaj Riska
Keyword(s):  
Water Resistance ◽  
Open Water ◽  
Full Scale ◽  
Ice Thickness ◽  
Total Resistance ◽  
Conservation Of Energy ◽  
Ship Resistance ◽  
Level Ice ◽  
Ice Resistance ◽  
Ship Speed

This paper presents results from the investigation of ship resistance on first year level ice in the Barent Sea. The basis for the work is the availability of full scale measurement data obtained on board of KV Svalbard in 2007. Measurements were made of the ice thickness, ship speed over ground in addition to setting power. The ice thickness was measured by means of an electromagnetic device, which enables careful selection of the time sequences for which level ice is present. By utilizing Newton II law and conservation of energy, the total resistance can be determined. The ice resistance in level ice was then obtained by subtracting the open-water resistance from the total resistance. The open-water resistance was measured when the ship was traveling in open water during the expedition. The relationship between the ship resistance and the ship speed over ground in level ice was finally obtained and compared with the Lindqvist formulation of estimation of ice resistance.

scholarly journals Formulation of Ice Resistance in Level Ice Using Double-Plates Superposition

2020 ◽  
Vol 8 (11) ◽  
pp. 870
Author(s):  
Liang Li ◽  
Qingfei Gao ◽  
Alexander Bekker ◽  
Hongzhe Dai
Keyword(s):  
Elastic Plate ◽  
Approximate Model ◽  
Ice Thickness ◽  
Full Scale Test ◽  
Ship Resistance ◽  
Bending Resistance ◽  
Level Ice ◽  
Scale Test ◽  
Coulomb Criterion ◽  
Ice Resistance

The estimation of ship resistance in ice is a fundamental area of research and poses a substantial challenge for the design and safe use of ships in ice-covered waters. In order to estimate the ice resistance with greater reliability, we develop in this paper an improved Lindqvist formulation for the estimation of bending resistance in level ice based on the superposition of double-plates. In the developed method, an approximate model of an ice sheet is firstly presented by idealizing ice sheeta as the combination of a semi-infinite elastic plate and an infinite one resting on an elastic foundation. The Mohr–Coulomb criterion is then introduced to determine the ice sheet’s failure. Finally, an improved Lindqvist formulation for estimation of ice resistance is proposed. The accuracy of the developed formulation is validated using full-scale test data of the ship KV Svalbard in Norway, testing the model as well as the numerical method. The effect of ice thickness, stem angle and breadth of bow on ship resistance is further investigated by means of the developed formulation.

A Three-Dimensional Plasticity and Momentum Model for Ship Resistance in Level Ice

1991 ◽  
Vol 113 (1) ◽  
pp. 53-60 ◽  
Author(s):  
C. H. Luk
Keyword(s):  
Numerical Methods ◽  
Equations Of Motion ◽  
Three Dimensional ◽  
Analytical Techniques ◽  
Full Scale ◽  
Momentum Balance ◽  
Ship Resistance ◽  
Plastic Limit Analysis ◽  
Level Ice ◽  
Ice Resistance

In this paper, a three-dimensional analysis is presented for calculating the level ice resistance for ships that have conventional hull forms. Comparisons with published ship resistance data and other analytical predictions are also provided. The present approach combines two analytical techniques: 1) plastic limit analysis is used to describe the ice failure mechanism and the associated ice velocity field; and 2) linear and angular momentum balances determine the average ice resistance for a ship. In the momentum balance, potential flow theory is used to describe the water motion induced by the icebreaking process. Existing methods for determining ship resistance in ice include numerical methods which depend on solutions of equations of motion that describe the dynamic interaction between the ice and the ship, and empirical methods which depend on model and full-scale icebreaker data to generate empirical correlations for ship resistance. The present results compare reasonably well with published model-scale and full-scale icebreaker data. Comparisons with predictions based on other numerical methods are also discussed.

scholarly journals An Approach to Determine Optimal Bow Configuration of Polar Ships under Combined Ice and Calm-Water Conditions

2021 ◽  
Vol 9 (6) ◽  
pp. 680
Author(s):  
Hui Li ◽  
Yan Feng ◽  
Muk Chen Ong ◽  
Xin Zhao ◽  
Li Zhou
Keyword(s):  
Numerical Simulation ◽  
Water Resistance ◽  
Numerical Technique ◽  
Experimental Studies ◽  
Resistance Index ◽  
Simulation Method ◽  
Present Approach ◽  
Calm Water ◽  
Level Ice ◽  
Ice Resistance

Selecting an optimal bow configuration is critical to the preliminary design of polar ships. This paper proposes an approach to determine the optimal bow of polar ships based on present numerical simulation and available published experimental studies. Unlike conventional methods, the present approach integrates both ice resistance and calm-water resistance with the navigating time. A numerical simulation method of an icebreaking vessel going straight ahead in level ice is developed using SPH (smoothed particle hydrodynamics) numerical technique of LS-DYNA. The present numerical results for the ice resistance in level ice are in satisfactory agreement with the available published experimental data. The bow configurations with superior icebreaking capability are obtained by analyzing the sensitivities due to the buttock angle γ, the frame angle β and the waterline angle α. The calm-water resistance is calculated using FVM (finite volume method). Finally, an overall resistance index devised from the ship resistance in ice/water weighted by their corresponding weighted navigation time is proposed. The present approach can be used for evaluating the integrated resistance performance of the polar ships operating in both a water route and ice route.

Model Tests in Brash Ice Channels

2005 ◽  
Author(s):  
Jens-Holger Hellmann ◽  
Karl-Heinz Rupp ◽  
Walter L. Kuehnlein
Keyword(s):  
Perforated Plate ◽  
Ice Sheet ◽  
Open Water ◽  
Model Tests ◽  
Ice Thickness ◽  
Special Device ◽  
Level Ice ◽  
Set Up ◽  
Parental Level ◽  
Oil Tankers

According to the present Finnish-Swedish Ice Class Rules (FSICR) the formulas for the required main engine power for tankers led to much bigger main engines than it is needed for the demanded open water speed. Therefore model tests may be performed in order to verify the vessel’s capability to sail with less required power in brash ice channels compared to the calculations. Several model test runs have been performed in order to study the performance of crude oil tankers sailing in brash ice. The tests were performed as towed propulsion tests and the brash ice channel was prepared according to the guidelines set up by the Finnish Maritime Administration (FMA). The channel width was 2 times the beam of the tanker. The model tests were carried out at a speed of 5 knots. For the tests a parental level ice sheet of adequate thickness is prepared according to HSVA’s standard model ice preparation procedure. After a predefined level ice thickness has been reached, the air temperature in the ice tank will be raised. An ice channel with straight edges will be cut into the ice sheet by means of two ice knives. The ice stripe between the two cuts will be manually broken up into relatively small ice pieces using a special ice chisel and if required the brash ice material will be compacted. Typically the brash ice thickness will be measured prior the tests at 9 positions across the channel and every two meter over the entire length of the brash ice channel with a special device, which consists of a measuring rule with a perforated plate mounted under a right angle at the lower end of the rule. As a result of the tests it could be demonstrated that tankers with a capacity of more than 50 000 tons require 50% and even less power compared to calculations using the present FSICR formulas.

scholarly journals Numerical Simulation of a Polar Ship Moving in Level Ice Based on a One-Way Coupling Method

2020 ◽  
Vol 8 (9) ◽  
pp. 692
Author(s):  
Bao-Yu Ni ◽  
Zi-Wang Chen ◽  
Kai Zhong ◽  
Xin-Ang Li ◽  
Yan-Zhuo Xue
Keyword(s):  
Numerical Simulation ◽  
Failure Process ◽  
Coupling Method ◽  
Crack Propagation Process ◽  
Order Of Magnitude ◽  
Level Ice ◽  
Ice Failure ◽  
Ice Resistance ◽  
Ship Speed ◽  
Good Agreement

In most previous ice–ship interaction studies involving fluid effects, ice was taken as unbreakable. Building breakable level ice on water domain is still a big challenge in numerical simulation. This paper overcomes this difficulty and presents a numerical modeling of a ship moving in level ice on the water by using a one-way CFD-DEM (computational fluid dynamics-discrete element method) coupling method. The detailed numerical processes and techniques are introduced. The ice crack propagation process including radial and circular cracks have been observed. Numerical results are compared with previous experimental data and good agreement has been achieved. The results show that water resistance is an order of magnitude smaller than ice resistance during the ice-breaking process. Ice resistance shows strong oscillation along with ice failure process, which are affected by ship speed and ice thickness significantly.

Progressing from 1D to 2D and 3D near-surface airborne electromagnetic mapping with a multisensor, airborne sea-ice explorer

Geophysics ◽  
2012 ◽  
Vol 77 (4) ◽  
pp. WB109-WB117 ◽  
Author(s):  
Andreas A. Pfaffhuber ◽  
Stefan Hendricks ◽  
Yme A. Kvistedal
Keyword(s):  
Sea Ice ◽  
Three Dimensional ◽  
Open Water ◽  
Ice Thickness ◽  
Receiver Coil ◽  
Differential Gps ◽  
Sea Ice Thickness ◽  
Near Surface ◽  
Level Ice ◽  
Ice Pressure

The polar ocean’s sea ice cover is an unconventional and challenging geophysical target. Helicopter electromagnetic (HEM) sea-ice thickness mapping is currently limited to 1D interpretation due to traditional procedures and systems. These systems are mainly sensitive to layered structures, ideally set for the widespread flat (level) ice type. Because deformed sea ice (e.g., pressure ridges) is 3D and usually also heterogeneous, ice thickness errors up to 50% can be observed for pressure ridges using 1D approximations for the interpretation of HEM data. We researched a new generation multisensor, airborne sea ice explorer (MAiSIE) to overcome these limitations. Three-dimensional finite-element modeling enabled us to determine that more than one frequency is needed, ideally in the range 1–8 kHz, to improve thickness estimates of grounded sea-ice pressure ridges that are typical of 3D sea ice structures. With the MAiSIE system, we found a new electromagnetic concept based on one multifrequency transmitter loop and a 3C receiver coil triplet with active digital bucking. The relatively small weight of the EM components freed enough payload to include additional scientific sensors, including a cross-track lidar scanner and high-accuracy inertial-navigation system combined with dual-antenna differential GPS. Integrating the 3D ice-surface topography obtained from the lidar with the EM data at frequencies from 500 Hz to 8 kHz in [Formula: see text]-, [Formula: see text]-, and [Formula: see text]-directions, significantly increased the accuracy of sea-ice pressure-ridge geometry derived from HEM data. Initial test flight results over open water showed the proof-of-concept with acceptable sensor drift and receiver sensitivity. Noise levels were relatively high (20–250 parts-per-million) due to unwanted interference, leaving room for optimization. The 20 ppm noise level at 4.1 kHz is sufficient to map level ice thickness with 10 cm precision for sensor altitudes below 13 m.

Experimental Investigation of Aspects Influencing the Level Ice Resistance of Ships With Non-Typical Icebreaking Bow Shapes

2021 ◽  
Author(s):  
Daniela Myland ◽  
Quentin Hisette ◽  
Emre Cilkaya ◽  
Yusuf Sefa Özhan
Keyword(s):  
Ice Sheets ◽  
Relevant Information ◽  
Interaction Process ◽  
Total Resistance ◽  
Ship Model ◽  
Load Cells ◽  
Level Ice ◽  
Ice Resistance ◽  
Different Thickness ◽  
Ice Model

Abstract For non-typical icebreaking ships the hull-ice interaction process in level ice comprises a combination of many different phenomena which is difficult to be described by existing straightforward approaches. In order to gain knowledge about the operability of such non-typical hull shapes in level ice, a study has been carried out to identify and evaluate the level ice resistance as well as its distribution along the hull of ships with non-typical icebreaking bow shapes with high stem and/or small waterline angles. For this purpose, one ship model has been manufactured and instrumented with several multi-axis load cells in the bow region of the waterline as well as with one large six-component load scale between the bow and the stern. Performing resistance model tests at several loading conditions in model ice sheets of different thickness and at multiple speed values allows obtaining relevant information to meet the goals of the study. The developed methodology and the analysis of the measured loads have been described in previous publications. As direct continuation, the present paper focuses on investigation of the ice floe characteristics and its linkage to the ice properties. Moreover, analysis results related to the crushing portion of the total resistance in ice, the friction between ice and ship model hull as well as the ship model motions during ice model testing are presented within the paper.

The Study on the Ice Sea Trial in Chukchi Sea Using Korean Icebreaker “Araon”

2011 ◽  
Author(s):  
Hyun Soo Kim ◽  
Chun-Ju Lee ◽  
Kyungsik Choi
Keyword(s):  
Chukchi Sea ◽  
Video Recording ◽  
The Arctic ◽  
Research Vessel ◽  
Ice Thickness ◽  
Sea Trial ◽  
Level Ice ◽  
Ice Strength ◽  
Ice Floes ◽  
Ship Speed

The ice sea trial measurement in Chukchi Sea using research vessel Araon was performed on July 2010. It was the first voyage to the Arctic Sea. The latitude of the route was between 73 degree north to 80 degree north. Araon is the first Korean Ice breaking research vessel. The principle dimension is 110m length, 19m beam and 7.3m draft. Araon was designed to break 1.0m level ice of 630 kPa flexible ice strength. Four attempts to know the performance of the ship in Arctic region were carried out and the results were summarized in this paper. The basic datum for the sea trial such as ship speed, power of engine, wind speed, location of the ship, air temperature, drafts, heading of the ship etc., were measured during the trail in every second by the video recording. Simultaneously the ice information such as ice thickness, compressive strength, temperature of ice, snow depth, free board of ice floe were measured in each field by the coring tool, auger and compression test equipment. The ice sea trial was performed in large ice floes rather than level ice because the sea ice condition on July and August in Chukchi Sea has no uniform level ice and starts to melt. The size of four ice floes is about 100m to 300m length and 100m to 200m wide beam. It was some second year ice and most of first year ice floes. The mean flexible strength of ice was less than 250 kPa. The analysis result of the ice sea trial shows the relation between the ice thickness, ice strength, ship speed and power of engine. Araon is possible to operate at 1.5 knots in 2.5m ice thickness with 5 MW engine power when the strength of ice floe is 250 kPa. The speed reaches 3.1 knots at same ice condition if the power is increasing up to 6.6 MW. She has good performance compare to the design target (3 knots in 1.0m level ice and 630 kPa of flexible strength) but it’s come from the different ice types and low flexible ice strength. The more detail analysis result was discussed in this paper.

Simulation of Ice Force and Breaking Pattern for Icebreaking Ship in Level Ice

2017 ◽  
Author(s):  
Junji Sawamura ◽  
Yutaka Yamauchi ◽  
Keisuke Anzai
Keyword(s):  
Numerical Model ◽  
Model Test ◽  
Ice Thickness ◽  
Broken Ice ◽  
Level Ice ◽  
Ice Force ◽  
Bending Failure ◽  
2D Numerical Model ◽  
Ship Speed ◽  
Good Agreement

A 2D numerical model was proposed to predict the repetitive icebreaking pattern and ice force of an advancing ship in level ice are presented. The numerical model focuses on the icebreaking at the waterline and neglects the broken ice rotating and sliding underwater hull. The repeated ship-ice contact and bending failure of a floating ice along the waterline are evaluated numerically. The computed ice channel width and icebreaking resistance are compared with measured values in the model test. Numerical results show moderately good agreement with the model test data. The effects of ice thickness and ship speed on the icebreaking resistance are investigated numerically. The icebreaking resistance depends on both the ice thickness and ship speed. The ice channel, however, depends on ice thickness, but there is little difference in ship speed.

Effect of Ship Speed on Level Ice Edge Breaking

2014 ◽  
Author(s):  
Mahmud Sazidy ◽  
Claude Daley ◽  
Bruce Colbourne ◽  
Jungyong Wang
Keyword(s):  
Ice Thickness ◽  
Linear Elastic ◽  
Flexural Failure ◽  
Management Capability ◽  
Speed Range ◽  
Level Ice ◽  
Ice Wedge ◽  
Ice Edge ◽  
Ship Speed ◽  
Good Agreement

This paper presents a numerical model of ship ice-wedge interaction to study the effect of ship speed on level ice edge breaking. The interaction process is modeled using LS-DYNA. The developed model considers ice crushing, ice flexural failure and the water foundation effect. For the ice, two different plasticity-based material models are used to represent ice crushing and ice flexural behaviors. The water foundation effect is modeled using a simple linear elastic material. The analysis is performed for a ship speed range of 0.1 to 5 ms−1 and ice thickness of 0.5 to 1.5 m. The analysis indicates that both ship speed and ice thickness significantly affect the ice breaking process. The model results are in good agreement with a number of analytical and empirical models. The model can be useful in establishing a rational basis for safe speed criteria, improving ship structural standards and tools for ice management capability assessment.

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