DTIC AD-A234 538 SSC-353 U- ELECTE iAP RI 1 1991 - ANALYSIS OF WAVE CHARACTEISTICS IN EXTREME SEAS. focr i!:w oed sift; Its i be a s ib lnm tl ed SHIP STRUCTURE COMMITTEE 1991 ,_991 4 10 083 SHIP S'TRUCTURE COMMITTEE The SHIP STRUCTURE COMMITTEE is constituted to prosecute a research program to improve the hull structures of ships and other marine structures by ar extension of knowledge pertaining to design, materials, and methods of construction. RADM J. D. Sipes, USCG, (Chairman) Mr. H. T. Hailer Chief, Office of Marine Safety, Security Associate Administrator for Ship- and Environmental Protection building and Ship Operations U. S. Coast Guard Maritire Administration Mr. Alexander Malakhoff Mr. Thomas W. Allen Director, Structural Integrity Engineering Officer (N7) Subgroup (SEA 55Y) Military Seaift Command Naval Sea Systems Command Dr. Donald Liu CDR Michael K. Parmelee, USCG, Senior Vice President Secretary, Ship Structure Committee American Bureau of Shipping U. S. Coast Guard CONTRACTING OFFICER TECHNICAL REPRESENTATIVES Mr. William J. Siekierka Mr. Greg D. Woods SEA 55Y3 SEA 55Y3 Naval Sea Systems Command Naval -Q-aS ystems Command SHIP STRUCTU RE.,AJJCMMIJIEE The SHIP STRUCTURE SUBCOMMITTEE acts for the Ship Structure Committee on technical matters by providing technical coordination for determinating the goals and objectives of the program and by evaluating and interpreting the results in terms of structural design, construction, and operation. AMERICAN BUREAU OF SHIPPING NAVAL SEA SYSTEMS COMMAND Mr. Stephen G. Arntson (Chairman) Mr. Robert A. Sielski Mr. John F. Conlon Mr. Charles L. Null Dr. John S. Spencer Mr. W. Thomas Packard Mr. Glenn M. Ashe Mr. AJlen H. Engle MILITAR1Y SEALIFT COM ND U.S. COAST GURD Mr. Albert J. Attermeyer CAPT T. E. Thompson Mr. Michael W. Touma CAPT Donald S. Jensen Mr. Jeffery E. Beach CDR Mark E. Noll MARITIME ADMINISTRATION Mr. Frederick Seibold Mr. Norman 0. Hammer Mr. Chao H. Lin Dr. Walter M. Maclean 1J1-PS-QTECIa SUBCOMMITTEE LIAISON-MEMIJEEIS .L5--QQATUD-AQAEMY NATIONAL ACDEMY OF $CIE - MARINEBOARQ LT Bruce Mustain Mr. Alexander B. Stavovy NATIONAL ACADEMY OF SCIENCES - Dr. C. B. Kim .QMMITEEON MARINE STRUCTURES Q.,.NAVALACADEMY Mr. Stanley G. Stiansen Dr. Ramswar Bhattacharyya SQ.E. LQF-NAVAL. ARCHITECTS AND M6RINE ENGINEERS - UN IVERSTQENWYQK 'YDRODYNAMISQCOMMITTEE Dr. William Sandberg Dr. W. R. Porter AMERICAN IRON AND STEEL INSTITU_] Mr. Alexander D.W ilson Dr. Martin Prager Member Agencies: Address Correspondence to: United States Coast Guard 1 Secretary, Ship Structure Committee Naval Sea Systems Command Ship U.S. Coast Guard (G-MTH) Marime Administration 2100 Second Street S.W. American Bureau of Shipping Structure Washington, D.C. 20593-0001 Military Sealift Command PH: (202) 267-0003 Committee FAX: (2C2) 267-0025 An Interagency Advisory Committee Dedicated to the Improvement of Marine Structures SSC-353 January 31, 1991 SR-1309 ANALYSIS OF WAVE CHARACTERISTICS IN EXTREME SEAS It is important that we have the ability to characterize and model the nonlinear wave forms of extreme seas as we continue to develop advanced ship designs. This report presents the method used to analyze nonlinear time series data and includes results from towing tank experiments where nonlinear extreme wave spectra were replicated. This information should prove to be quite useful in assessing loads imposed on hull structures. Rear Admiral, U.S. Coast Guard Chairman, Ship Structure Committee ~I i\A_ W . , 'it. Technical Report Documentation Page 1. Report No. 2. Government Accession No. 3. Recipient's Catalog No. SSC-353 4. Title and Subtitle 5. Report Dote Analysis of Wave Characteristics in AUGUST 1989 Extreme Seas 6. Performing Organization Code 8. Performing Organization Report No. 7. Author's) SR-1309 William H. Buckley 9. Performing Organization Name and Address 10. Work Unit No. (TRAIS) DAVID TAYLOR RESEARCH CENTER Code 1730.6 11. Contract or Grant No. Eethesda, MD 20048-5000 DTCG23-87-F-10030 13. Type of Report and Period Covered 12. Sponsoring Agency Name and Address Final Report Commandant U.S. Coast Guard 2100 Second Street, SW 14. Sponsoring Agency Code Washington, DC 20593 G-M 15 Supplinientary Notes Sponsored by the Ship Structure Committee and its member agencies. 16. Abitruct The'4esults from three studies concerning identification and charActerization of extreme waves in storm driven seaways are presented. Methods and results using time-series wave height data from hurricane Camille are illustrated. Task 1 demonstrated the utility of the half-cycle matrix (HACYM) method in analyzing nonlinear time-series data. Task 2 involved wave making experiments where the Camille nonlinear wave spectrum was replicated. Task 3, using second order wave-wave interaction theory, provided a nonlinear time domain wave height model conforming to the Camille nonlinear wave spectrum. In Task 1, the HACYM analysis of input and output realizations from Dalzell's nonlinear simulation model showed that this analysis method provides a clear indication of the nonlinearity of a time series random variable. In Task 2, the nonlinearity ol waves generated in two different towing tanks approached that of the original Camille seaway when the wave spectrum was approximated by mechanically generated waves. In Task 3, while numerically modeled hurricane Camille time series waves showed somewhat less nonlinearity than the original time series data, the flattening of wave troughs and elevations of crests due to nonlinear wave-wave interaction was realistic. ., Available from: 17. Key Words 18. Distribution Statement Wave Characteristics Nat'l Technical Information Service Extreme Seas Springfield, VA 22161 or Nonlinear Wave Spectrum Marine Tech. Information Facility Wave Modeling National Maritime Research Center Half-Cycle Matrix Method Kings Point, NY 10024-1699 19. Security Clissif. (of this rdot) 20. Security Classif. (of this page) 21. No. of Pages 22. Price Unaassified Unclassified 182 Form DOT F 1700.7 (8-72) Reproduction of completed page authorized _0 . 00 * 0 U 0 U -0 .;. UE E z 1 1tU i lt O 1 1 s If i z 1 LU I.- . E E E U a~~ 00c ma UL em? ? 1? 6 ? 9 ~ ~ J! 0t I ? !~ TABLE OF CONTENTS Page 1.0 INTRODUCTION ........................................................ 1 2-.0 BACKGROUND .......................................................... 2 3.0 HALF-CYCLE ANALYSIS OF A RANDOM NONLINEAR RESPONSE VARIABLE ......... 6 4.0 FURTHER ANALYSIS OF HURRICANE CAMILLE WAVE DATA ..................... 24 5.0 TOWING TANK MODELING OF A NONLINEAR RANDOM SEAWAY ................... 32 6.0 NUMERICAL MODELING OF A NONLINEAR RANDOM SEAWAY ..................... 45 7.0 OVERVIEW OF RESULTS AND RECOMMENDED DEVELOPMENT INITIATIVES ......... 51 8.0 CONCLUSIONS ......................................................... 68 9.0 RECOMMENDATIONS ..................................................... 69 ACKNOWLEDGEMENTS 70 REFERENCES 71 APPENDIX A - THE HACYM METHOD OF RANDOM DATA ANALYSIS 73 APPENDIX B - SYNOPSIS OF REFERENCE (3) 78 APPENDIX C - ARCTIC OFFSHORE CORPORATION LETTER REPORT AOC-87-432, 83 SIMULATION OF CAMILLE WAVE SPECTRUM IN THE TEST BASIN LT ARCTIC OFFSHORE CORPORATION, DECEMBER 1987. APPENDIX D - DAVIDSON LABORATORY TECHNICAL REPORT SIT-DL-87-9-2595, 117 GENERATION OF HURRICANE CAMILLE WAVES IN A TOWING TANK, NOVEMBER 1987. APPENDIX E - NUMERICAL MODEL OF A NONLINEAR RANDOM SEAWAY. 168 iii LIST OF FIGURES Page 1 Formation of Statistics Associated with HACYM Distributions ......... 3 - 2 - Maximum Measured Significant Wave Heights vs Frequency Corresponding to Modal Frequency (From Reference 5). .............................. 8 3 - Simulated Time Histories of Nonlinear Response to Random Excitation: Sample 1, a = 1.0 ................................................... 10 4 - Simulated Time Histories of Nonlinear Response to Random Excitation: Sample 1, a = 0.25 .................................................. 11 5 - HACYM Analysis of Linear Gaussian Wave Input to Dalzell's Nonlinear Response Simulation ................................................. 12 6 - HACYM Analysis of Linear Constituent of Output of Dalzell's Non- linear Response Simulation .......................................... 13 7 - HACYM Analysis of Quadratic Constituent of Output of Dalzell's Nonlinear Response Simulation ....................................... 15 8 - HACYM Analysis of Cubic Constituent of Output of Dalzell's Nonlinear Response Simulation ................................................. 16 9 - HACYM Analysis of Combined Output (L+Q+C) of Dalzell's Nonlinear Response Simulation, a = 0.25 ....................................... 18 10 - Comparison of Marginal Distributions of Half-Cycle Events with Maxima and Minima Distributions from Dalzell's Nonlinear Simulation (L+Q+C) ............................................................. 19 11 - HACYM Analysis of Combined Output (L+Q) of Dalzell's Nonlinear Response Simulation, a = 1.0).................................20 12 - HACYM Analysis of Combined Output (L+Q+C) of Dalzell's Nonlinear Response Simulation, a x = 1.0 .................................. 21 13 - HACYM Analysis of Input Wave Spectrum Modified to Approximate Results of Zero Up/Down Crossing Analysis ........................... 25 14 - Mean Value Distribution of Amplitude Events from HACYM Analysis of Hurricane Camille Wave Data ......................................... 26 15 - Significant Wave Height, Average Wind Velocity and Spectrum Peaked- ness vs Time During Hurricane Camille (1000-1618 Hours) ............. 29 16 - Wave Spectra from Hurricane Camille ................................. 30 17 - Comparison of Desired and Achieved Wave Spectra from A.O.C. Experi- ment (Full Scale) ................................................... 34 18 - HACYM Analysis of Wave Probe Measurements from A.O.C. Experiment .... 35 19 - Time Series Characteristics at Highest Waves of Primary Probe - A.O.C. Experiment ......... ......................................... 36 20 - Time Series Characteristics of Highest Waves - Hurricane Camille 1500-1530 Hours ..................................................... 38 21 - Comparison of Desired and Achieved Wave Spectra from D.L. Experiment (Model Scale) ....................................................... 39 22 - HACYM Analysis of Wave Probe Measurements from D L. Experiment ...... 40 iv LIST OF FIGURES (CONTINUED) Page 23 - Time Series Characteristics of Highest Waves at Primary Probe - D.L. Experiment .......................................................... 42 24 - Time Series Wave Heights from Staggered Wave Probes for Model Scale Plunging Breaker - Hydromechanics Laboratory, USNA .................. 44 25 - Time Series Comparison of Model Scale Plunging Breaker and Wave From Hurricane Camille (1522 hours) ...................................... 45 26 - Spectrum from Wave Gage 2 for 60 Minute Simulation Using JONSWAP Spectrum ............................................................ 46 27 - Comparison of Waves of Highest Elevation/Amplitude Ratio from A.O.C. Test Runs 1001 and 2000 ............................................. 46 28 - Simulated Time Series of Numerical Model of Nonlinear Random Seaway - Camille 1500-1530 Hours ............................................. 48 29 - HACYM Analysis of Numerical Model of Nonlinear Random Seaway - Camille 1500-1530 Hours ............................................. 49 30 - Time Series Characteristics of Highest Waves in Numerical Model of Nonlinear Random Seaway - Camille 1500-1530 Hours ................... 50 31 - Abstract of Deck Log frcm S.S. SEA-LAND MARKET in Southwest Wind Field of Winter Storm ............................................... 60 32 - Half Cycle Analysis of SL-7 Pitch Angle rita for Two Severe Operat- ing Conditions ...................................................... 61 33 - Half Cycle Analysis of SL-7 Midship Bending Stress Data for Two Severe Operating Conditions ......................................... 62 34 - Half Cycle Analysis of SL-7 Roll Angle Data for Two Severe Operat- ing Conditions ...................................................... 63 35 - Extract from "Motions and Capsizing in Astern Seas" (Ref. 16) ....... 66 LIST OF TABLES I - An Initial Characterization of Large Nonlinear and Episodic Waves (Rev. A). ........................................................... 7 2 - Characterization of Largest Waves in Test Tank Experiment ............ 41 3 - Characterizatio of Largest Waves in Numerical Model ................. 47 4 - Recommend Development Initiatives .................................... 57 v NOTATION e/a, elevation amplitude ratio defined as the mean value of a wave height half-cycle event divided by its amplitude; generally trough to peak. fp, frequency at peak of a unimodal wave height spectrum. Hm significant wave height = 4[m5]V 0, Hmax, maximum trough to peak or peak to trough wave height in a particular realization. Hd, trough to peak wave height. H/L, ratio of wave height to length. (L+Q), sum of linear and quadratic constituents in Dalzell's simulation. (L+Q+C), sum of linear, quadratic and cubic constituents. S(f), wave spectrum energy density at frequency f. T... time duration of a trough to peak wave height event. Tp , modal period corresponding to fp. X(t), time series realization of Dalzell's input wave spectrum. Yl(t), linear constituent of time series response in Dalzell's simulation. Y2(t), quadratic constituent of time series response. Y3(t), cubic constituent of time series response. Y(t), sum of Yl(t) + Y2(t) + Y3(t). 6, spectrum bandwidth parameter, [mam m-MI 4 where m, = S(f) df m, =JS(f) f4 df 0, standard deviation 9- = input excitation employed in Dalzell's simulation. vi ABBREVIATIONS AOC, Arctec offshore Corporation, Escondido, Calif. DL, Davidson Laboratory of Stevens Institute of Technology, Hoboken, N.J. DTRC, David Taylor Research Center, Bethesda, MD. HACYM, half-cycle matrix; used to analyze successive peak/trough statistics of stochastic data. MVDAE, mean value distribution of amplitude events in a HACYM. ZUC, zero up-crossing method of analyzing trough to peak wave height events in tiri series data. vii