Form Approved
REPORT DOCUMENTATION PAGE
OMB No. 0704-0188
Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the
data needed, and completing and reviewing this collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing
this burden to Department of Defense, Washington Headquarters Services, Directorate for Information Operations and Reports (0704-0188), 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302.
Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to any penalty for failing to comply with a collection of information if it does not display a currently valid
OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS.
1. REPORT DATE (DD-MM-YY)
2. REPORT TYPE
3. DATES COVERED (From - To)
August 2000
Technical Report
4. TITLE AND SUBTITLE
5a. CONTRACT NUMBER
5b. GRANT NUMBER
Ship Superstructure Icing: Crystalline and Physical Properties
5c. PROGRAM ELEMENT NUMBER
6. AUTHOR(S)
5d. PROJECT NUMBER
Charles C. Ryerson and Anthony J. Gow
5e. TASK NUMBER
5f. WORK UNIT NUMBER
7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES)
8. PERFORMING ORGANIZATION REPORT
NUMBER
U.S. Army Engineer Research and Development Center
Cold Regions Research and Engineering Laboratory
72 Lyme Road
ERDC/CRREL TR-00-11
Hanover, New Hampshire 03755-1290
9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES)
10. SPONSOR / MONITOR'S ACRONYM(S)
Office of the Chief of Engineers
U.S. Navy Office of Naval Research
Washington, DC
Washington, DC
11. SPONSOR / MONITOR'S REPORT
NUMBER(S)
12. DISTRIBUTION / AVAILABILITY STATEMENT
Approved for public release; distribution is unlimited.
Available from NTIS, Springfield, Virginia 22161.
13. SUPPLEMENTARY NOTES
14. ABSTRACT
In February and March 1990, measurements were made of superstructure ice on a United States Coast Guard cutter in the Bering Sea. Ice
samples were removed from bulkheads, decks, and icicles during two icing events. Ice crystal measurements included crystal size, shape,
orientation, brine pocket location, size and shape, internal layering, and air bubble sizes. Ice property measurements included salinity,
density, and temperature, with computed estimates of air and brine volume. Texturally, accreted ice resembled frazil ice that forms from the
consolidation of freely nucleated ice crystals in sea water. This resemblance is also reflected in bulk salinities, ranging from 7 to 24‰. The
crystalline structure of accreted ice ranged from rounded to polygonal. Generally, rounded crystals would be expected for ice formed from
sea spray droplets. The occurrence of polygonal crystals is attributed to thermally driven modification after deposition. No trend towards
reorientation of crystallographic c-axes in either freshly accreted or thermally modified ice was observed. Mean crystal sizes ranged from
0.56 to 1.15 mm, with even larger crystals in icicles. Ice salinity averaged about 12‰ on bulkheads and about 21‰ on decks. Ice densities
ranged from 0.69 to 0.92 Mg m3 and were generally higher on decks. Bulkhead ice had larger computed total porosity and air volume, and
lower brine volume than deck ice. Samples taken from decks and bulkheads generally compared well with Russian and Japanese measure-
ments.
15. SUBJECT TERMS
Crystal structure
Saline spray ice
Physical properties
Ship icing
16. SECURITY CLASSIFICATION OF:
17. LIMITATION OF
18. NUMBER
19a. NAME OF RESPONSIBLE PERSON
OF ABSTRACT
OF PAGES
a. REPORT
b. ABSTRACT
c. THIS PAGE
19b. TELEPHONE NUMBER (include area code)
U
U
U
U
43
Standard Form 298 (Rev. 8-98)
]Prescribed by ANSI Std. 239.18
to contents
Previous Page
