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Analysis of the Properties of Fast Ferry Wakes in the Context of Coastal Management

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Analysis of the Properties of Fast Ferry Wakes in the Context of Coastal Management THESIS ON CIVIL ENGINEERING F24 Analysis of the Properties of Fast Ferry Wakes in the Context of Coastal Management DMITRY KURENNOY TUT PRESS TALLINN UNIVERSITY OF TECHNOLOGY Institute of Cybernetics Faculty of Civil Engineering Department of Building Production The dissertation was accepted for the defence of the degree of Doctor of Philosophy on 27 August 2009 Supervisors: Prof. Tarmo Soomere Institute of Cybernetics Tallinn University of Technology Dr. Ira Didenkulova Institute of Cybernetics Tallinn University of Technology Department of Probability and Statistics University of Sheffield, UK Opponents: Dr. Boris V. Chubarenko Head of Laboratory for Coastal Systems Study Atlantic Branch, P. P. Shirshov Institute of Oceanology Russian Academy of Sciences Dr. Robert Aps Head of the Department of Marine Systems Estonian Marine Institute, University of Tartu Defence of the thesis: 08 October 2009 Declaration: Hereby I declare that this doctoral thesis, my original investigation and achievement, submitted for the doctoral degree at Tallinn University of Technology has not been submitted for any academic degree. /Dmitry Kurennoy/ Copyright: Dmitry Kurennoy, 2009 ISSN 1406-4766 ISBN 978-9985-59-935-8 EHITUS F24 Kiirlaevalainete omaduste analüüs rannikualade haldamise kontekstis DMITRY KURENNOY TUT PRESS Contents LIST OF TABLES AND FIGURES ...........................................................................................6 INTRODUCTION...................................................................................................................... 8 WAVES FROM HIGH-SPEED VESSELS ...................................................................................8 VESSEL WAVES AS A CHALLENGE FOR COASTAL MANAGEMENT.........................................9 OUTLINE OF THE THESIS ...................................................................................................11 APPROBATION OF THE RESULTS........................................................................................13 ACKNOWLEDGEMENTS.....................................................................................................14 1. SHIP WAVES AS A POTENTIAL COASTAL HAZARD......................................... 15 1.1. LARGE-SCALE MARINE COASTAL HAZARDS .......................................................15 1.2. THE ROLE OF SURFACE WAVES AMONG COASTAL HAZARDS...............................19 1.3. SHIP WAKES AS A COASTAL ENGINEERING PROBLEM..........................................21 1.4. POTENTIAL OF SHIP WAKES FOR THE MITIGATION OF DISASTERS........................22 1.5. CONCLUDING REMARKS.....................................................................................23 2. EXPERIMENTAL STUDY OF SHIP WAKES IN TALLINN BAY......................... 24 2.1. STUDY SITE ........................................................................................................24 2.2. THE FLEET: CHARACTERISTICS OF THE SHIPS .....................................................25 2.3. WAVE MEASUREMENTS .....................................................................................27 2.4. DATA PROCESSING.............................................................................................29 3. STATISTICAL PROPERTIES OF SHIP WAKES .................................................... 32 3.1. WAVE HEIGHTS..................................................................................................32 3.2. WAKE ENERGY...................................................................................................35 3.3. ENERGY FLUX ....................................................................................................40 3.4. CONCLUDING REMARKS.....................................................................................43 4. NONLINEAR (CNOIDAL) WAVES IN SHIP WAKES ............................................ 44 4.1. INTRODUCTION ..................................................................................................44 4.2. CREST-TROUGH ASYMMETRY OF SHIP WAVES....................................................45 4.3. CNOIDAL WAVE THEORY: AN APPLICATION TO SHIP WAVES...............................49 4.4. CONCLUDING REMARKS.....................................................................................52 5. RUNUP OF SHIP WAVES ON A BEACH.................................................................. 53 5.1. INTRODUCTION ..................................................................................................53 5.2. MEASUREMENTS OF WAVE RUNUP ON A BEACH .................................................53 5.3. WAVE RUNUP DATA ...........................................................................................55 5.4. CONCLUDING REMARKS.....................................................................................58 CONCLUSIONS ...................................................................................................................... 59 SUMMARY OF RESULTS ....................................................................................................59 MAIN CONCLUSIONS PROPOSED TO BE DEFENDED ............................................................61 RECOMMENDATIONS FOR FURTHER STUDY ......................................................................62 BIBLIOGRAPHY .................................................................................................................... 64 PAPERS ON WHICH THE THESIS IS BASED ..........................................................................64 LIST OF REFERENCES ........................................................................................................64 ABSTRACT.............................................................................................................................. 72 5 RESÜMEE................................................................................................................................73 APPENDIX A: CURRICULUM VITAE ............................................................................... 74 APPENDIX B: ELULOOKIRJELDUS ................................................................................. 81 Keywords: surface waves, fast-speed ferries, ship wakes, Tallinn Bay, Baltic Sea, wave statistics, coastal zone, wave measurements, wave shoaling, wave runup, marine natural hazards, coastal engineering, coastal zone management. List of Tables and Figures Table 2.1. Ships operating the Tallinn–Helsinki ferry link in summer 2008. The Superfast represents a family of several sister ships Table 3.1. High speed ships operating the Tallinn–Helsinki ferry link in summer 2008 (Paper IV) and wave height on days with a comparatively low wind wave background (28–30 June, 1–9, 12, 13 and 20 July 2008). Unidentified wakes belong to smaller or slower ships sailing to Helsinki or to ships sailing to Tallinn Table 3.2. Wake energy and power integrated over the duration of the wakes Fig. 2.1. The Baltic Sea and Tallinn Bay. The bold line in the lower right panel indicates the approximate route of fast ferries (Paper IV) Fig. 2.2. Sequence of vessel wakes on weekdays in summer 2008 (Paper IV) Fig. 2.3. The recorded sailing line and depth Froude numbers of the SuperSeaCat on 29–30 June 2008 (left). The eastern track is used by outbound ships and the western track by inbound ships. A simulation shows wake-waves at a single point (Torsvik et al., 2009). The SW coast of Aegna (a) and water depths around Aegna jetty (b) showing the location of runup measurements (A3) and tripod (A4) Fig. 2.4. (a) Record of water surface elevation on 5 July 2008, calm conditions and (b) 9 July 2008, transition to storm conditions Fig. 2.5. Waves from the SuperSeaCat on 3 July 2008 at 21:40: (a) original, (b) after filtering Fig. 3.1. Maximum wave height within 2.5-min sections on 5 July 2008. Almost all spikes higher than 15 cm correspond to ship wakes (Paper II) Fig. 3.2. Daily maximum ship wave heights. Squares reflect unfiltered data and circles, data filtered using a low-pass filter with a cut-off frequency at 0.4 Hz (Paper IV) Fig. 3.3. Frequency of occurrence of maximum wave heights in wakes from different ships (Paper II) Fig. 3.4. Total wave energy density on 4–6 July (black line) and the energy density of wind wave fields at 00:30–07:30 on the same days (grey lines) (Paper IV) 6 Fig. 3.5. Daily average energy density of ship wakes, estimated from the energy in long components with periods >8 s. Days with missing data due to maintenance are not represented Fig. 3.6. Frequency of occurrence of total energy in wakes from different ships Fig. 3.7. Frequency of occurrence of total energy flux in wakes from different ships Fig. 4.1. Cnoidal ship waves in Tallinn Bay Fig. 4.2. Average values and standard deviation of asymmetry coefficients calculated with the use of zero-upcrossing and zero-downcrossing methods Fig. 4.3. Empirical distributions of the asymmetry coefficient for the waves from the first group of the wake for different vessels Fig. 4.4. Scatter diagram of the occurrence of different values of the asymmetry coefficient for waves with different height from the first group of the wakes: contour plot (left); 3D surface plot (right) Fig. 4.5. Scatter diagram of the occurrence of different values of the asymmetry coefficient for waves of different periods from the first group of the wakes: contour plot (left); 3D surface plot (right) Fig. 4.6. Scatter diagram of the occurrence of different values of the asymmetry coefficient for waves with different height from the first
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