Aaron Tam A systematic analysis of test-based model-scale icebreaking patterns Master’s Thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Technology Espoo 31.08.2019 Supervisor: Professor Pentti Kujala Director: Professor Pentti Kujala Aalto-yliopisto, PL 11000, 00076 AALTO www.aalto.fi Diplomityön tiivistelmä Author Aaron Tam Title of thesis A systematic analysis of test-based model-scale icebreaking patterns Master program Cold Climate Engineering Code ENG25 Thesis supervisor(s) Professor Pentti Kujala Thesis advisor(s) Knut Høyland Fang Li Date 31.08.2019 Number of pages 143 Language English Abstract The study of icebreaking patterns has been sparsely studied over the course of the past half century. Various methods have been developed primarily to approximate the size of the resultant cusps and general inferences from the observations of the cusps and relating properties. The objective of this work aims to compile the current state of the art in this field and perform model tests focusing on icebreaking pattern. The resultant cusps of the tests were recorded, measured, compiled, statisti- cally fit, and analyzed in works with comparing to currently available approximation methods as well as revisit any current theories regarding the nature of icebreaking pattern and its scalability. The cusps and patterns formed from model tests from the Azipod-version model of the MT Uikku at slow speeds were used for the comparison and analysis. The tests show primarily the confirma- tion of most current theories with an exception to one criterion regarding elasticity, promoted po- tential prospects for scaling, and found greater accuracy from theoretical and full-scale based ap- proximation methods as opposed to model scale prediction methods. Keywords model testing in ice, icebreaking pattern, ice cusps Acknowledgements I sent my warm thanks to Aalto University, the Norwegian University of Science and Technology, and the Nordic Master’s Cold Climate Engineering Program for allowing me to study and pursue educational and scholarly development in this field. I would like to thank my supervisor, Pentti Kujala for the opportunity for me to pursue this study and all the corresponding experimental work involved, and Knut Høyland for his guidance and input throughout the course of the study. I am very thankful for the guidance by my thesis advisor, Fang Li, for assisting me throughout the span of this endeavor in the theoretical, experimental, and analytical work involved. My gratitude extends also to the Aalto University Ice Tank Manager, Otto Puolakka, and the Aalto Ice Tank Lab Technicians, Teemu Päivärinta and Lasse Turja for all their help in making the model tests possible and converting the data from the instrumentation. Ad- ditionally, I send my thanks to all my colleagues at the Aalto University Ice Tank for their assistance and input throughout the course of my work. Lastly, I would like to express my thanks to all my friends and family for all their love and support throughout the course of my studies. Espoo, August 2019 Aaron Aaron Tam Table of Contents Abstract Acknowledgements 1 Introduction ......................................................................................................................... 1 1.1 Introduction of icebreaking patterns ....................................................................... 1 1.2 Research Questions ................................................................................................. 1 2 State of the Art and Theory ................................................................................................. 3 2.1 Icebreaking pattern definition ................................................................................. 3 2.1.1 Scalability of Cusps ......................................................................................... 4 2.1.2 Icebreaking Pattern .......................................................................................... 8 2.1.3 Thickness Dependency .................................................................................. 13 2.1.4 Speed Dependency ......................................................................................... 14 2.1.5 Load Length Dependency .............................................................................. 16 2.2 Methods of Approximation ................................................................................... 18 2.2.1 Statistical – McKindra and Lutton’s Bay Class Fit (1981) ............................ 18 2.2.2 Statistical – Izumiyama’s Cone Circles (1992) ............................................. 20 2.2.3 Semi-Empirical – Kostras’s Semi-Ellipse (1983) .......................................... 21 2.2.3.1 Applied Numerical Model – Liu et al (2006) ......................................... 22 2.2.4 Semi-Empirical – Tatinclaux’s Shapes (1985) .............................................. 23 2.2.5 Semi-Empirical – Wang’s Circles (2001) ...................................................... 24 2.2.5.1 Applied Numerical Model – Su (2011) .................................................. 25 2.2.6 Theoretical – Nevel’s Elastically Founded Semi-Inf Plate (1958) ................ 25 2.2.6.1 Modified Nevel – Lubbad and Løset’s Radial Wedges (2011) .............. 27 2.2.6.2 Modified Nevel – Li’s Discretized Wedges (2019) ............................... 28 2.2.7 Theoretical – Erceg’s Discretized Beams (2015) .......................................... 31 2.2.8 Numerical – Valanto’s 3D Hydrodynamic Solution (2001) .......................... 32 2.2.9 Numerical – Sawamura FEM Solution (2008) .............................................. 33 2.2.10 Numerical – Summary of Methiod ................................................................ 34 2.3 Model Testing in Ice ............................................................................................. 35 3 Method .............................................................................................................................. 38 3.1 Aalto Ice Tank ....................................................................................................... 38 3.2 MT Uikku Testing ................................................................................................. 40 3.2.1 Past MT Uikku Tests ...................................................................................... 41 3.2.2 Experiment Preparations ................................................................................ 42 3.2.3 Model Tank Testing ....................................................................................... 44 3.3 Digital Processing ................................................................................................. 46 3.3.1 Video Processing ........................................................................................... 46 3.3.2 Image Processing ........................................................................................... 47 3.4 Prediction Methods ............................................................................................... 49 3.4.1 Statistical Prediction ...................................................................................... 50 3.4.2 Analytical Prediction ..................................................................................... 51 3.4.3 Theoretical Prediction .................................................................................... 52 3.4.4 Dimension Conversion .................................................................................. 55 4 Results and Discussions .................................................................................................... 57 4.1 Results and Observations ...................................................................................... 57 4.2 Single vs Multiple Contact .................................................................................... 58 4.3 Prediction Method Comparison ............................................................................ 61 4.4 Scalability .............................................................................................................. 69 4.5 Icebreaking Pattern ................................................................................................ 70 4.6 Distribution Fitting ................................................................................................ 72 5 Conclusion ........................................................................................................................ 75 6 Bibliography ..................................................................................................................... 78 7 List of Appendices ............................................................................................................ 81 Appendix A - Cusp Data Table .......................................................................................... A-1 Appendix A.1 V=0.162m/s Single Contact Cusp Data ............................................... A-2 Appendix A.2 V=0.162m/s Multiple Contact Cusp Data ......................................... A-10 Appendix A.3 V=0.270m/s Single Contact Cusp Data ............................................. A-14 Appendix A.4 V=0.270m/s Multiple Contact Cusp Data ......................................... A-22 Appendix B - Icebreaking Pattern Photographs ................................................................ B-1 Appendix C - Distributions and Histograms .....................................................................