Research on the Influences of Broken Ice Parameters on Maneuverable Forces of Ice-Going Ship Oblique Sailing

2021 ◽  
Author(s):  
Shenyu Xuan ◽  
Chengsheng Zhan ◽  
Zuyuan Liu ◽  
Binfeng He ◽  
Qiaosheng Zhao ◽  
...  
Keyword(s):  
Time History ◽  
Test Results ◽  
Ship Maneuvering ◽  
Average Value ◽  
Ocean Science ◽  
Broken Ice ◽  
Ice Conditions ◽  
Ice Field ◽  
Ice Resistance ◽  
Good Agreement

Abstract The broken ice is one of the most common ice conditions for ice-going ships, and the research of ship maneuvering movement in broken ice field can improve sailing safety. In this paper, the discrete element method (DEM) was adopted to study the maneuverable forces, including resistance and transverse force, of ice-going ship oblique sailing in broken ice fields. First, the Araon model tests data of Korea Institute of Ocean Science & Technology (KIOST) was used to verify the ice resistance of direct sailing under different ice sizes and model speeds, and the numerical results are in good agreement with the test results. Second, the influences of broken ice parameters (including concentration, thickness, and shape) on ship-ice interaction and maneuverable forces distribution were researched. The maneuverable forces on the ice-going ships are mainly from the ship-ice interaction. The time history curves of maneuverable forces were analyzed from the average value of maneuverable forces, the average value of peak maneuverable forces, and the number of peaks. Besides, the parameters of broken ice have a heavy influence on the movement of broken ice around the hull, such as accumulating and sliding. The analysis of the broken ice movement contributes to understanding the influences of broken ice parameters on ice-going ships.

Numerical Simulation of Model Test in Pre-Sawn Ice by CFD-DEM Coupled Method

2021 ◽  
Author(s):  
Dong Cheol Seo ◽  
Jungyong Wang
Keyword(s):  
Model Test ◽  
Design Stage ◽  
Early Design Stage ◽  
Actual Application ◽  
Broken Ice ◽  
Ice Conditions ◽  
Ice Field ◽  
Grid Technique ◽  
Ship Performance ◽  
Ice Resistance

Abstract Arctic shipping activities have been steadily increased due to global warming and economic benefit. As a result, there are more demands to estimate the ship performance in various ice conditions at the early design stage. In this paper, a CFD-DEM coupled approach was applied to estimate the ice resistance and broken ice behavior around the hull including hydrodynamic interactions. For the simulation, the moving ship in the stationary ice field was implemented using the overset grid technique. The estimated ice resistance as well as ice behaviors around the hull from the simulations were compared with model test results and underwater videos of the same vessel in a similar ice condition. The results demonstrated good agreement with model test measurements and further improvement for actual application was discussed in the paper.

Dynamic Test of Bird Strike on a Flat Plate Made from LY-12 Aluminium

2013 ◽  
Vol 765-767 ◽  
pp. 3158-3161
Author(s):  
Jun Liu ◽  
Zheng Li Zhang
Keyword(s):  
Numerical Simulation ◽  
Dynamic Response ◽  
Dynamic Test ◽  
Time History ◽  
Aircraft Design ◽  
Bird Strike ◽  
Test Results ◽  
Valuable Data ◽  
Good Agreement ◽  
Peak Value

Tests of bird strike have been carried out on plate made from LY-12 Aluminium. The test was down with the projectile impacting the target perpendicularly at velocity of 40m/s, 80m/s, 120m/s respectively. The displacement-time history curves and strain-time history curves of on LY-12 Aluminium plate were measured. The good agreement of the results between two specimens in one group indicated that the results tested in the presnet paper are reliable. The dynamic response of the plate and damage modes of the bird influenced by striking velocity were analyzed. The peak value of the displacement linear enlarged with the increasing of the striking velocity. The test results in the present paper provided valuable data for aircraft design impacted by bird, and also provided abundant test datas for the numerical simulation model applied in bird striking.

Laboratory Testing of a Flexible Boom for Ice Management

1993 ◽  
Vol 115 (3) ◽  
pp. 149-153 ◽  
Author(s):  
S. Lo̸set ◽  
G. W. Timco
Keyword(s):  
Oil Spills ◽  
The Arctic ◽  
Small Scale ◽  
Test Results ◽  
Offshore Structure ◽  
Video Cameras ◽  
Ice Concentration ◽  
Broken Ice ◽  
Ice Field ◽  
Force Components

Combatting oil spills in the Arctic is a major challenge. Drilling or producing oil or gas in the marginal ice zone (MIZ) may allow booms to be deployed upstream of an offshore structure to clear the water of ice, thereby enabling conventional oil spill countermeasures to be used. Such a boom would be kept in place by two ice-going service vessels or by moored buoys. SINTEF NHL and NRC have performed a number of small-scale tests with a flexible boom in the NRC ice basin in Ottawa. The purpose of the tests was to measure the effectiveness of using a flexible boom for collecting ice, and to determine the loads associated with collecting the ice. In the tests, various boom configurations were towed against a broken ice field consisting of ice pieces typically 50–100 mm across and 30 mm thick. The ice concentration was usually 10/10, but it was reduced to 8/10 and 5/10 for two tests. The boom was towed at speeds of 20 and 50 mm-s−1. Both the width of the boom and the slackness of the boom were varied over reasonable ranges. Two six-component dynamometers were used to support the boom. Thus, the force components on each end of the boom were measured. Further, two video cameras were used to record the effectiveness of each boom configuration. In this paper, the full results of this test program are presented and the application of the test results to the full-scale situation are discussed. The tests show that, under certain conditions, the use of boom is feasible for ice management in oil-contaminated water.

Image Processing for the Analysis of an Evolving Broken-Ice Field in Model Testing

2012 ◽  
Author(s):  
Qin Zhang ◽  
Solange van der Werff ◽  
Ivan Metrikin ◽  
Sveinung Løset ◽  
Roger Skjetne
Keyword(s):  
Image Processing ◽  
Water Area ◽  
Test Results ◽  
Detection Algorithms ◽  
Ice Concentration ◽  
Broken Ice ◽  
Ice Field ◽  
Ice Floes ◽  
Processing Techniques ◽  
Ice Forces

Dynamic positioning (DP) experiments in model ice were carried out in the ice tank at the Hamburg Ship Model Basin (HSVA) in the summer of 2011. In these experiments the behavior of two different ships in a broken-ice field were studied. One of the main parameters characterizing a broken-ice field is the ice concentration, defined as the fraction of the total water area covered by ice. In this paper, image processing techniques are applied to derive the ice concentration in the model basin. Several points in time are analyzed in order to describe the evolution of the ice field. The applied techniques include methods for identifying individual ice floes and calculating the ice concentration in the vicinity of the model ship. Ice floe boundaries are then obtained, and the ice floe size distribution and shape factor may further be extracted from the images. The image processing methods applied in this work are object extraction and edge detection algorithms, which are further customized to ice identification. The obtained results can be used for relating the ice field characteristics to the model test results, such as the vessel’s displacements and the corresponding ice forces.

Oil Behaviour in Ice-Infested Waters

2014 ◽  
Vol 2014 (1) ◽  
pp. 1239-1250 ◽  
Author(s):  
M.F. Fingas ◽  
B.P. Hollebone
Keyword(s):  
Current Knowledge ◽  
Measurement Techniques ◽  
Petroleum Products ◽  
Small Scale ◽  
Oil Transport ◽  
Ice Melt ◽  
Broken Ice ◽  
Ice Conditions ◽  
Ice Field ◽  
Ultimate Fate

ABSTRACT The current knowledge of the physical fate and behaviour of crude oil and petroleum products spilled in Arctic situations is reviewed. Oil in and under ice undergoes a variety of processes depending on location and environmental conditions. Modeling of oil in such environments becomes complex by the addition of these processes. Spreading was evaluated for oil on ice, under ice, in snow, in brash ice, and between blocks of ice. Oil transport under sheet and broken ice are considered, both for sea and river conditions. The movement of oil under the ice may be governed by the undersea roughness as well as the relative velocity of the water with respect to the ice. The effects of oil on a growing ice sheet are examined, both for its effects on ice formation and for the thermal effects of oil inclusions in ice. The migration of oil through ice is examined, focussing primarily on the movement through brine channels. The effects of oil on the surface of ice are considered, with emphasis on the effects of surface pools on ice melt. Similar consideration is given to the effects of oil on snow on the surface of ice. The quantitative studies of oil in open and dynamic ice conditions are reviewed. Observations of intentional small-scale spills in leads and ice fields are reviewed and compared with observations from real spills. The most common ultimate fate of oil in an ice field is release onto water. Some of the measurements made in earlier years suffered from the lack of good measurement techniques. Further research is needed to improve the understanding of oil behavior in ice-infested waters.

Discrete Element Modelling of Pack Ice Interaction With Floating Structures

2015 ◽  
Author(s):  
Jie Dai ◽  
Heather Peng
Keyword(s):  
Discrete Element ◽  
Wave Force ◽  
Interaction Force ◽  
Discrete Element Modelling ◽  
Empirical Formulas ◽  
Pack Ice ◽  
Broken Ice ◽  
Ice Conditions ◽  
Ice Field ◽  
Ice Floes

This paper presents a two-dimensional numerical model for ship-ice interaction simulatiion using the discrete element method (DEM). The simulation was conducted for a broken ice field with hundreds of circular ice floes and various combinations of ice conditions. A viscous-elastic ice rheology was adopted to model the dynamic behavior of each individual ice floe. Both ship-ice and ice-ice contacts were considered in the interaction force. Environment forces, including wind force and wave force, were calculated by empirical formulas. An algorithm was developed to log each contact and solve motions of individual ice floe and the ship. The resistance of ship advancing in ice was predicted and compared with model test results.

Development of the Analysis Procedure for the Ice-Induced Fatigue Damage of a Ship in Broken Ice Fields

2020 ◽  
Vol 142 (6) ◽  
Author(s):  
Jeong-Hwan Kim
Keyword(s):  
Fatigue Damage ◽  
Interaction Model ◽  
Local Stress ◽  
Analysis Model ◽  
Element Analysis ◽  
Ice Load ◽  
Broken Ice ◽  
Ice Conditions ◽  
The Baltic ◽  
Ice Resistance

Abstract A simplified analysis method was developed to evaluate the fatigue damage of an ice-going ship under broken ice conditions. The ice resistance, which is available in the early design stages of an ice-going vessel, and the hull form information were used to estimate the local ice load acting on the outer-shell of the ship. The local ice load was applied to a finite element analysis model, and the Weibull parameters of the local stress range at the target fatigue point were derived. Finally, the fatigue damage was evaluated by applying the S–N curve and Palmgren–Miner rule. To verify the proposed method, numerical analyses using the direct approach, which takes into account the detailed interaction model among the fluid, structure, and ice, were performed under the same conditions. Fatigue analyses of the Baltic Sea for actual ice conditions were performed to check the validity and applicability of the proposed method, and the resulting fatigue damage was compared with that obtained by the classification society’s recommended practice.

Numerical Simulation of the Ice Resistance in Pack Ice Conditions

2019 ◽  
Vol 17 (01) ◽  
pp. 1844005 ◽  
Author(s):  
Biye Yang ◽  
Guiyong Zhang ◽  
Zhigang Huang ◽  
Zhe Sun ◽  
Zhi Zong
Keyword(s):  
Fluid Model ◽  
Hydrodynamic Performance ◽  
Arbitrary Lagrangian Eulerian ◽  
Interaction Technique ◽  
Eulerian Formulation ◽  
Pack Ice ◽  
Ice Conditions ◽  
Ice Field ◽  
Oil Tanker ◽  
Ice Resistance

In this study, the ice resistance of ship under the pack ice condition has been estimated using Multi-Material Arbitrary Lagrangian–Eulerian formulation and penalty-based fluid–structure interaction technique. Especially, the hydrodynamic loads occurring during the ship–ice interaction were combined in the numerical model, which could be important for simulating pack ice conditions. The feasibility of the hydrostatic and hydrodynamic performance in the fluid model was verified, respectively. By using an ice field generation algorithm to generate randomly distributed pack ices, the ice resistance of an oil tanker has been calculated and validated by comparing with the empirical formula. Moreover, the necessity to consider water effect in the interaction between ship and ice was also discussed.

PENGARUH MODEL PEMBELAJARAN KELILING KELOMPOK (ROUND CLUB) TERHADAP KETERAMPILAN MENULIS LAPORAN PERJALANAN SISWA KELAS V SDN 01 NAGARI BUKIK SIKUMPA

2020 ◽  
Author(s):  
Wirda Linda
Keyword(s):  
Standard Deviation ◽  
Performance Test ◽  
Writing Skills ◽  
Learning Model ◽  
Homogeneity Test ◽  
Test Results ◽  
Class V ◽  
Average Value ◽  
Normality Test ◽  
Lecture Method

This research is motivated by the low desire of students in writing travel reports. The lack of students' knowledge of the report concept, the lack of students' knowledge of the 5W + 1H report points of good and correct language, the lack of students' knowledge of the spatial, time and topic pattern and not yet reached KKM 75. The method used by the teacher has not been interesting, lecture method. The purpose of this study is to describe the skills of writing travel reports by using Round Club learning model which is viewed from the aspect of understanding the report concept, the use of 5W +1H report points, the spatial, time, and topic pattern.The population of this study is the students of class V Lessons Year 2017/2018 which amounted to 2 classes with the number 80. The sample of research as much as two classes taken by the sample of propotional.Class V.1 as experimental class and class V.2 as control class. The research instrument used is performance test. Provide an assessment by specifying the subject of the 5W + 1H report, as well as the spatial, time and topic pattern. Data were analyzed by 't' test by first testing normality, homogeneity, and hypothesis testing.The results showed that the average control class 68 with more than enough qualifications with standard deviation 16.96. 83 experimental class with good qualification and standard deviation of 15.42 and there is a significant influence on the result of writing skill of class V SDN 01 Nagari Bukik SikumpaSubdistrict, Lima Puluh Kota. This is evidenced by the average value of writing skills in the experiment class higher than the average value in the control class. Normality test results indicate that the two sample classes of  Lo  values in the control class -0.2141 are smaller than the normal 0.190 Lt distributed. Homogeneity test results that the variation of this study is homogeneous at a real level of 0.05, because Ftable 2.16 > Fhitung 1.21 and the results of data analysis then obtained = 2.78 > 1.70 t table, so H0 rejected and H1 accepted. It can be concluded that there is Influence. Using  Learning  Model of Student Group Writing  Skills Travel Report of students of class V SDN 01 Nagari Bukik Sikumpa Subdistrict, Kabupaten Lima Puluh Kota.KeyWords: model pembelajaran round club, menulis laporan perjalanan.

scholarly journals Spine Examination during COVID-19 Pandemic via Video Consultation

2021 ◽  
Author(s):  
Tom Jansen ◽  
Martin Gathen ◽  
Amadeo Touet ◽  
Hans Goost ◽  
Dieter Christian Wirtz ◽  
...  
Keyword(s):  
Pain Intensity ◽  
Range Of Motion ◽  
Test Results ◽  
Risk Of Infection ◽  
Face To Face ◽  
Reliable Tool ◽  
Provocation Tests ◽  
Active Range Of Motion ◽  
Video Consultation ◽  
Good Agreement

Abstract Introduction During the current COVID-19 pandemic video consultations are increasingly common in order to minimize the risk of infection for staff and patients. The aim of this study was to evaluate the feasibility of a spine examination via video. Methods A total of 43 patients were recruited. Each participant underwent a video-based (VB) and a conventional face-to-face (FTF) spine examination. Pain intensity, active range of motion, inspection, a neurophysiologic basic exam and provocations tests were evaluated using video-based and face-to-face methods. Results The intra-rater reliability (IRR) was measured between both examinations. Good to very good IRR values were obtained in inspection (Kappa between 0,752 und 0,944), active range of motion and basic neurophysiological examination (Kappa between 0,659 und 0,969). Only moderate matches were found in specific provocation tests (Kappa between 0,407 und 0,938). A video-based spine examination is a reliable tool for measuring pain intensity, active range of motion and a basic neurophysiologic exam. Conclusion A basic spine examination during a video consultation is possible. A good agreement of the test results between video-based and face-to-face examination could be found.

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