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.

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.

Interaction of Ice Floes With Columns of a Semi-Submersible Platform

1983 ◽  
Vol 105 (4) ◽  
pp. 460-463
Author(s):  
P. G. Noble ◽  
D. Singh
Keyword(s):  
Maximum Load ◽  
Test Results ◽  
Ice Load ◽  
Physical Model Tests ◽  
Ice Concentration ◽  
Drilling Unit ◽  
Ice Loads ◽  
Ice Field ◽  
Preliminary Research ◽  
Ice Floes

A preliminary research project has been carried out to determine the effect of small ice floes on a semi-submersible drilling unit. Physical model tests have been conducted with two main objectives: first, to determine the ability of the columns to prevent ice from passing between them (arching) and thus minimizing the chance of riser damage, and second, to determine the total ice load on the semi-submersible during interaction with ice field concentrations. Three models were used, representing one half of a four, six or eight-legged semi-submersible platform. The dimensions and spacing of the columns were such that the heave and pitch responses were kept constant. The tests were conducted at a model scale of 1:30 using synthetic ice. Test results showed the maximum load measured on a four-legged semi-submersible model, at 100 percent ice floe concentration, was on the order of half of that measured on six or eight-legged semi-submersible models. Also the ice loads on a four-legged semi-submersible model at lower ice floe concentration were substantially less than those for six or eight-legged semi-submersible models. The total ice load on semi-submersible models is found to be a function of ice floe concentration. Up to about 75 percent ice concentration, ice loads varied linearly. Beyond that, the loads increased exponentially for all semi-submersible models.

OHMSETT TESTS OF A ROPE-MOP SKIMMER IN ICE-INFESTED WATERS1

1985 ◽  
Vol 1985 (1) ◽  
pp. 31-34 ◽  
Author(s):  
J. S. Shum ◽  
M. Borst Mason & Hanger-Silas
Keyword(s):  
Oil Spill ◽  
Oil And Gas ◽  
Oil Spills ◽  
Arctic Region ◽  
Cold Weather ◽  
The Arctic ◽  
Test Tank ◽  
Broken Ice ◽  
Petroleum Development ◽  
Oil Spill Cleanup

ABSTRACT The increase in petroleum development activities in the arctic region has raised concerns over potential oil spills during the broken ice season. Currently, exploratory drilling for oil and gas is restricted during this season due to the lack of proven oil spill cleanup methods for broken ice fields. Test programs have been conducted at the U.S. Environmental Protection Agency's Oil and Hazardous Materials Simulated Environmental Test Tank (OHMSETT) to determine the feasibility of cold weather testing and to evaluate various oil spill cleanup methods considered for use in the arctic. This paper describes a test program to determine the practicality of using a catamaran-mounted rope-mop skimmer for spill cleanup in broken ice fields. An Oil Map Pollution Control, Ltd., prototype arctic skimmer was tested in the test tank under controlled conditions during January 30 to February 7, 1984. Freshwater ice cubes of 250 to 280 millimeters (mm) were used in the tests to approximate a broken ice field. During tests, a predetermined ice condition was established across the encounter width of the rope mops and oil was distributed over the ice. The oil and ice were channeled into the skimmer by two booms, which were joined to the skimmer at the bow. Nine tests were conducted at a tow speed of 1 knot using Circo 4X light oil. During the tests, ice concentrations were varied from 0 to 75 percent of the surface area, and oil slick thickness varied from 3 to 8 mm. The test results demonstrated the spill cleanup capability of the skimmer in ice-infested waters having up to 50 percent ice coverage. At higher ice concentrations, the skimmer was ineffective due to ice jamming at the skimmer inlet.

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.

scholarly journals Some engineering estimations of oil spill parameters in the marine environment

2018 ◽  
Vol 64 (2) ◽  
pp. 208-211 ◽  
Author(s):  
S. N. Zatsepa ◽  
A. A. Ivchenko ◽  
V. V. Solbakov ◽  
V. V. Stanovoy
Keyword(s):  
Oil Spill ◽  
Marine Environment ◽  
Oil Spills ◽  
Equations Of Motion ◽  
Ice Cover ◽  
The Arctic ◽  
Oil Flow ◽  
Ice Field ◽  
Drifting Ice ◽  
Similar Solutions

Estimation of the oil spill size at continuous spills on the moving sea surface or on the drifting ice field is the actual practical problem. Engineering estimation means the reduction of the hydrodynamic equations system to the balance of only two main forces that cause movement and resistance of the oil flow. From the simplified problem statement some practical relations were obtained for estimating the size of spill, including continuous oil spill with surface water currents presence, for spill onto porous snow-ice cover and onto the drifting ice cover. The obtained estimations can be used in more complicated models of oil spill transformation in the marine environment, primarily in the Arctic zone, and give basis for development of adequate responses on oil spills. The comparison of the obtained estimates with the self-similar solutions of the corresponding equations of motion of the spreading substance shows a satisfactory fit.

LASER IGNITION OF OIL SPILLS

1987 ◽  
Vol 1987 (1) ◽  
pp. 389-394 ◽  
Author(s):  
Harry Whittaker
Keyword(s):  
Engineering Design ◽  
Conceptual Development ◽  
Oil Spills ◽  
Laser System ◽  
Climatic Conditions ◽  
The Arctic ◽  
Laser Ignition ◽  
Broken Ice ◽  
Oil Rig

ABSTRACT A major oil spill in the Arctic, whether from a tanker or an oil rig, could result in large concentrations of oil among broken ice and/or thousands of oiled melt pools. The remoteness of the area and the inadequacy of other countermeasures make in-situ burning the only possible response. Helicopter-deployable igniters have been developed to ignite the oil, but studies have shown that use of these devices has severe logistical constraints. The use of a helicopter-borne laser system as an alternative to, or in conjunction with, the igniters has been pursued from conceptual development to completion of the engineering design phase. The concept was examined by theoretical analysis combined with laboratory studies. This work indicated that a dual-laser system would ignite both fresh and weathered crude oils at temperatures representative of an arctic spring or fall day. A series of outdoor experiments was carried out in Kanata, Ontario, Canada, in March 1985. These experiments, under climatic conditions very similar to those in the Canadian Arctic in June, demonstrated that a two-laser system would ignite both fresh and weathered crudes. An engineering feasibility and design study was undertaken. The study confirmed that a system having the required performance can be assembled from existing, proven hardware and operated effectively from a helicopter. The development of the laser ignition of oil spills from concept through engineering design is described.

scholarly journals Quantitative Analysis of Ice Sheet Failure Against an Inclined Plane

1985 ◽  
Vol 107 (3) ◽  
pp. 381-387 ◽  
Author(s):  
R. M. W. Frederking ◽  
G. W. Timco
Keyword(s):  
Quantitative Analysis ◽  
Analytical Model ◽  
Ice Sheet ◽  
Offshore Structures ◽  
The Arctic ◽  
Inclined Plane ◽  
Broken Ice ◽  
Force Components ◽  
Crushing Behavior ◽  
Analytical Expressions

The main force components on inclined offshore structures in the Arctic include the flexural and crushing behavior of the ice sheet, rotation and translation of broken ice, gravity and buoyancy in lifting and moving ice, and friction between ice and structure. Tests were carried out to isolate these components and analytical expressions were derived for them. Measured and predicted components compare favorably, the analytical model overpredicting by about 20 percent.

scholarly journals Sea Ice Concentration Products over Polar Regions with Chinese FY3C/MWRI Data

2021 ◽  
Vol 13 (11) ◽  
pp. 2174
Author(s):  
Lijian Shi ◽  
Sen Liu ◽  
Yingni Shi ◽  
Xue Ao ◽  
Bin Zou ◽  
...  
Keyword(s):  
Time Series ◽  
Sea Ice ◽  
Ocean Circulation ◽  
The Arctic ◽  
Retrieval Algorithm ◽  
Atmospheric Effects ◽  
Observation Data ◽  
Long Time Series ◽  
Ice Concentration ◽  
Long Time

Polar sea ice affects atmospheric and ocean circulation and plays an important role in global climate change. Long time series sea ice concentrations (SIC) are an important parameter for climate research. This study presents an SIC retrieval algorithm based on brightness temperature (Tb) data from the FY3C Microwave Radiation Imager (MWRI) over the polar region. With the Tb data of Special Sensor Microwave Imager/Sounder (SSMIS) as a reference, monthly calibration models were established based on time–space matching and linear regression. After calibration, the correlation between the Tb of F17/SSMIS and FY3C/MWRI at different channels was improved. Then, SIC products over the Arctic and Antarctic in 2016–2019 were retrieved with the NASA team (NT) method. Atmospheric effects were reduced using two weather filters and a sea ice mask. A minimum ice concentration array used in the procedure reduced the land-to-ocean spillover effect. Compared with the SIC product of National Snow and Ice Data Center (NSIDC), the average relative difference of sea ice extent of the Arctic and Antarctic was found to be acceptable, with values of −0.27 ± 1.85 and 0.53 ± 1.50, respectively. To decrease the SIC error with fixed tie points (FTPs), the SIC was retrieved by the NT method with dynamic tie points (DTPs) based on the original Tb of FY3C/MWRI. The different SIC products were evaluated with ship observation data, synthetic aperture radar (SAR) sea ice cover products, and the Round Robin Data Package (RRDP). In comparison with the ship observation data, the SIC bias of FY3C with DTP is 4% and is much better than that of FY3C with FTP (9%). Evaluation results with SAR SIC data and closed ice data from RRDP show a similar trend between FY3C SIC with FTPs and FY3C SIC with DTPs. Using DTPs to present the Tb seasonal change of different types of sea ice improved the SIC accuracy, especially for the sea ice melting season. This study lays a foundation for the release of long time series operational SIC products with Chinese FY3 series satellites.

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